19M EDITION AIR BRAKE CATECHISM BLACKALL Class / r Book By GopigM? . COPYRIGHT DEPOSIT ^ UP-TO-DATE Air-Brake Catechism THE ONL.Y PRACTICAL AND COMPLETE WORK PUBLISHED, TREATING ON THE EQUIPMENT MANUFACTURED BY THE WESTINGHOUSE AIR BRAKE COMPANY, INCLUDING THE ET LOCOMOTIVE BRAKE EQUIPMENT ; THE K (QUICK-SERVICE) TRIPLE VALVE FOR FREIGHT SERVICE; THE TYPE L HIGH- SPEED TRIPLE VALVE; AND THE CROSS COMPOUND PUMP. THE OPERATION OF ALL PARTS OF THE APPARATUS IS EX- PLAINED IN DETAIL, AND A PRACTICAL WAY OF FINDING THEIR PECULIARITIES AND DEFECTS WITH A PROPER REMEDY IS GIVEN. 2,0 QUESTIONS WITH THEIR ANSWERS Are included. These are intended as examination questions for engineers and firemen, and all other railroad men, preparing to pass an examination on the subject of air brakes. This book has been endorsed and used by air-brake instructors and examiners on nearly every railroad in the United States By ROBERT H. BLACKALL Fully Illustrated by Detail Engravings and Colored Plates TWENTY-FIFTH EDITION Entirely Revised, Enlarged and Reset NEW YORK: THE NORMAN W. HENLEY PUBLISHING COMPANY 132 NASSAU STREET 1911 ^ Copyrighted 1911; 1908 and 1907 By THE NORMAN W. HENLEY PUBLISHING COMPANY Copyrighted 1903, 1900 and 1898 By NORMAN W. HENLEY & CO. r y Composition, Electrotyping and Presswork by Macgowan & ^ Slipper, New York City £. CI. A 2 8 9 ? 8 8 / tf THIS BOOK IS LOVINGLY DEDICATED TO MY FATHER AND MOTHER Preface to the Twenty-Fifth Edition THE fact that this is the twenty-fifth edition of this book indicates that there is an urgent need for a book of this nature written on the question and answer plan, by means of which it is possible to readily locate the particular point upon which information is desired. The air-brake art has almost completely changed in the last four or five years, hence the necessity for an entirely new edition. The changed conditions of service which now pre- vail, and which consist of longer trains, cars of heavier capacity and locomotives with power and weight com- mensurate with their increased duties, have made impera- tive some radical changes in the air brake. The original brake was designed with the idea in mind that the maxi- mum length of train would be fifty cars, and the capacity of these cars 60,000 pounds. A large percentage of the cars of to-day have a capacity of 100,000 pounds, the number of cars in a train is often 100 and the hauling power of the locomotive has kept pace. The result of these changes has been that the apparatus which has been in use for so many years is not adequate to handle, with the desired efficiency, the long and heavy trains of to-day. Passenger cars and engines have more than doubled in weight and it has also been necessary to re-design this equipment that stops may be possible within desirable and practical limits. To meet these changed conditions in freight service i PREFACE the Westinghouse Air Brake Company has developed new engine and car equipment by the use of which even better results are obtained with the long and heavy trains than could be obtained with the older equipment and shorter trains. They have also developed a passenger car equipment which, aside from the improvements in the way of flex- ibility and other new features, will permit of this heavier equipment being brought to a stop in about the same distance as was accomplished with the older form of high- speed brake and the lighter equipment in general use dur- ing the previous ten years. The author takes this opportunity of thanking those in- terested in the air-brake art for the generous and cordial support which former editions of this book have received. June, 1911. ROBERT H. BLACKALL. TABLE OF CONTENTS PAGE CHAPTER I. Beginnings of the Air Brake 17-20 CHAPTER II. The Westinghouse Triple Valves — The Plain Triple Valve — Functions of the Triple Valve in the Opera- tion of the Brake — Quick-Action Triple Valve — Pe- culiarities and Troubles of the Quick-Action Triple Valve— The Type "K" Triple Valve— The Type "L" Triple Valve 21-78 CHAPTER III. Westinghouse Freight Equipment — Piston Travel — The American Automatic Brake-Slack Adjuster and Piston-Travel Regulator — Pressure Retaining Valves 79-112 CHAPTER IV. Westinghouse Air Pumps — Nine and One-Half Inch Pump — Nine and One-Half Inch Pump, Peculiari- ties, Troubles, Care — Westinghouse "Right and Left-Hand" Nine and One-Half Inch Pump — Westing- house Eleven Inch Pump — The Eight and One-Half Inch Cross-Compound Pump — The Present Stand- ard (SF-4) Pump Governor 113-145 CHAPTER V. Main Reservoir — G-6 Engineer's Brake Valve — Westing- house Slide-Valve Feed Valve — The Equalizing Res- ervoir or, Little Drum, or Cavity D — Peculiarities and Troubles of the G-6 Brake Valve — Duplex Main-Reservoir Regulation, as Used with all Standard Westinghouse Equipments .»,♦.,.♦ ♦ . 146-177 TABLE OF CONTENTS. PAGE CHAPTER VI. Westinghouse Old-Style High-Speed Brakes — Double Pressure Control Equipment or Schedule U — Westinghouse Old-Style Combined Automatic and Straight Air-Brake Equipment for Engines and Tenders— Straight Air-Brake Valve 178-205 CHAPTER VII. The Westinghouse No. 6 ET Locomotive Brake Equip- ment — Brake Valves for ET Equipment — H-6 Auto- matic Brake Valve — The S-6 Independent Brake Valve — The No. 6 Distributing Valve — Independent Application — Automatic Operation — The Quick-Ac- tion Cylinder Cap — The Use of the Safety Valve — Feed Valves— The B-6 Feed Valve— The C-6 Reduc- ing Valve — The Pump Governor — Defects of ET Equipment — Principle Differences Between the No. 5 and No. 6 ET Equipments 206-260 CHAPTER VIII. Air-Signal System' — Peculiarities and Troubles of the Signal System , 261-273 CHAPTER IX. Braking, Power and Leverage — Sizes of Cylinders to be Used on Cars and Tenders — American Brake Lever- age — Cam Brake — Air Hose — Air-Brake and Signal- Hose Specifications — Bursting Test — Friction Test —Stretching Test . . 274-29S CHAPTER X. The Sweeney Compressor — The Water Brake — Water Brake on Simple Engine — 'The Baldwin Water Brake on Baldwin Compounds — Air-Brake Recording Gages— Lubricants 299-309 CHAPTER XL Train Inspection — Train Handling — Description of Tests —Piping 310-342 CHAPTER XII. A Few Practical Formulae and Rules for Air-Brake Inspectors 344-348 List of Illustrations OF WESTINGHOUSE AIR BRAKE AND SIGNAL EQUIPMENT Fig. 1. Old Style Plain Triple Valve, Release Position 23 Fig. 2. Plain Triple Valve, Service Position 25 Fig. 3. Plain Triple Valve, Lap Position 26 Fig. 4. Plain Triple Valve, Emergency Position 30 Fig. 4a. Colored Plate of Old Standard Quick-Action Triple Valve — Release and Charging Position. • • .facing 3(5 Fig. 5. Quick-Action Triple Valve, Release Position 37 Fig. 6. Quick- Action Triple Valve, Service Position....... 38 Fig. 7. Quick-Action Triple Valve, Lap Position 39 Fig. 8. Quick-Action Triple Valve, Emergency Position 42 Fig. 9. Slide Valve Bushing 43 Fig. 10. Slide Valve 43 Fig. 11. K Triple Valve — Exterior View 54 Fig. 12. K Triple Valve — Cross Section 55 Fig. 13. K Triple Valve — Graduating Valve, Slide Valve, and Slide-Valve Seat 57 Fig. 14. K Triple Valve— Full Release 58 Fig. 15. K Triple Valve — Service Position. 59 Fig. 16. K Triple Valve — Service-Lap Position. 60 Fig. 17. K Triple Valve — Retarded Release Position....... 61 Fig. 18. K Triple Valve — Emergency Position 62 Fig. 19. Type L Triple Valve 64 Fig. 20. Type L Triple Valve 65 Fig. 21. Diagram of Type L Triple Valve- Release and Charging Position 66 Fig. 22. Diagram of Type L Triple Valve— Quick-Service Position 67 Fig. 23. Diagram of Type L Triple Valve — Service-Lap Position 68 Fig. 24. Diagram of Type L Triple Valve— Full-Service Position 69 ^ LIST OF ILLUSTRATIONS. Fig. 25. Diagram of Type L Triple Valve— Release-Lap Position 70 Fig. 26. Diagram of Type L Triple Valve — Emergency Position 71 Fig. 27. Westinghouse Freight Equipment 80 Fig. 28. Showing Application of American Brake Slack Adjuster to a Passenger Car Equipment 95 Fig. 29. Sectional End View of American Automatic Brake- Slack Adjuster 97 Fig. 30. Showing Proper Method of Drilling Brake Cylinders When Used with the American Automatic Brake- Slack Adjuster 100 Fig. 31. Sectional View of Pressure-Retaining Valve 103 Fig. 32. The Westinghouse Double-Pressure Retaining Valve 105 Fig. 33. Retaining Valve Used with 12, 14, and 16-inch Brake Cylinders 110 Fig. 34. "Pullman" Retaining Valve, Used on Vestibule Cars 110 Fig. 35. Standard Retaining Valve Used with 6, 8 and 10-inch Brake Cylinders 110 Fig. 36. Driver-Brake Retaining Valve Ill Fig. 36a. Colored Plate— Nine and One-Half-Inch Pump . . facing 113 Fig. 37. Westinghouse 9%-inch Air Pump 114 Fig. 37a Westinghouse 9%-inch Air Pump 11 !> Fig. 38. Right and Left-Hand Pump 127 Fig. 39. Eight and One-Half Cross-Compound Pump 130 Fig. 40. Diagram of Cross-Compound Pump — Up Stroke High-Pressure Side 132 Fig. 41. Diagram of Cross-Compound Pump — Down Stroke, High-Pressure Side 133 Old Standard Pump Governor 140 Colored Plate — Present Standard (SF-4) Pump Gov- ernor facing 143 Main Reservoir Drain Cock 149 D-8 Engineer's Brake Valve — Release Position.... 151 G-6 Engineer's Brake Valve — Release Position.... 152 G-6 Engineer's Brake Valve — Running Position... 153 G-6 Engineer's Brake Valve — Plan View 154 Feed Valve — Section Through Supply Valve Piston 162 Feed Valve — Section Through Regulating Part.... 163 Rotary Valve of G-6 Brake Valve (top view) 161 Fig. 42. Fig. 43. Fig. 44. Fig. 45. Fig. 46. Fig. 47. Fig. 48. Fig. 49. Fig. 50. Fig. 51, LIST OF ILLUSTRATION'S. Fig. 52. Bottom View of Rotary Valve of G-6 Brake Valve.. 164 Fig. 53. The Little Drum, or Cavity D 167 Fig. 54. Diagram of Westinghouse Duplex Main — Reservoir Regulation 175 Fig. 55. Method of Drilling Brake Valve for Duplex Main — Reservoir Regulation 176 Fig. 56. Method of Drilling Brake Valve for Duplex Main — Reservoir Regulation 176 Fig. 57. High-Speed Automatic Reducing Valve 180 Fig. 57a. Diagrammatic Illustration of Old Style Westing- house High-Speed Brake Equipment 182 Fig. 58. Section of High-Speed Reducing Valve, Showing Position of Ports in Emergency Stop 184 Fig. 59. Section of High-Speed Reducing Valve, Showing Position of Ports with Cylinder Pressure Slightly Exceeding 60 Pounds 184 Fig. 60. Section of High-Speed Reducing Valve, Showing Position of Ports in Release Position 184 Fig. 61. Showing Location of High-Speed Automatic Reduc- ing Valve Under Car 186 Fig. 62. Progress of Air Brake Efficiency as Shown by Com- parative Distances in Which Trains Are Stopped 188 Fig. 62a. Diagrammatic Illustration of Westinghouse Double- Pressure Control Apparatus or Schedule U 190 Fig. 63. Old Style Safety Valve 192 Fig. 64. New Style Safety Valve 192 Fig. 64a. Combined Automatic and Straight Air Brake Equip- ment as Applied to Freight Engine and Tender 194 Fig. 65. Double Check Valve 196 Fig. 66. Straight-Air Brake Valve 199 Fig. 67. Straight-Air Brake Valve 199 Fig. 68. Straight-Air Brake Valve 200 Fig. 69. Straight-Air Brake Valve 200 Fig. 70. Section Through Straight-Air Brake Valve 200 Fig. 71. Colored Plate— Piping Diagram of No. 6 E T Equip- ment • • facing 207 Fig. 72. The H-6 Automatic Brake Valve 212 Fig. 73. Colored Plate— The H-6 Automatic Brake Valve facing 213 Fig. 74. Brake Valves — Positions of Handles..... 214 LIST OF ILLUSTRATIONS. Fig. 75. H-6 Automatic Brake Valve 216 Fig. 76. S-6 Independent Brake Valve 222 Fig. 77. Colored Plate— The S-6 Automatic Brake Valve facing 223 Fig. 78. Interior Views of the S-6 Independent Brake Valve 224 Fig. 78a. Distributing Valve in Released and Charging Position facing 228 Fig. 79. Distributing Valve and Double Chamber Reservoir 229 Fig. 80. Distributing Valve and Double Chamber Reservoir 229 Fig. 81. Release Position — Automatic or Independent..... 230 Fig. 82. Independent Application 231 Fig. 83. Independent Lap 232 Fig. 84. Automatic Service 233 Fig. 85. Service Lap 234 Fig. 86. Emergency 235 Fig. 87. Emergency Lap 236 Fig. 88. Independent Release When Brake Has Been Applied Automatically 237 Fig. 89. Emergency When the Quick-Action Cap Is Used.. 238 Fig. 90. Graduating Valve, Equalizing Slide Valve and Slide Valve Seat 239 Fig. 91. Distributing Valve, Showing Connections 242 Fig. 92. Quick-Action Cylinder Cap 248 Fig. 93. B-6 Feed Valve 252 Fig. 94. Single Equipment for Engine With Engines Not Equipped With Schedule E T 262 Fig. 95. Location of Signal Apparatus on Coach 263 Fig. 96. Air Strainer on Engine 264 Fig. 97. Car Discharge Valve 265 Fig. 98. Westinghouse Signal Valve 266 Fig. 99. Westinghouse Signal Reducing Valve 267 Fig. 100. Signal Whistle 268 Fig. 101. Lever of First Class 277 Fig. 102. Lever of First Class Applied to Car Wheel 279 Fig. 103. Lever of Second Class 280 Fig. 104. Lever of Second Class, Applied to Car Wheel 281 Fig. 105. Lever of Third Class 281 Fig. 106. Lever of Third Class, Applied to Car Wheel 281 Fig. 107. Hodge System of Leverage 283 Fig. 108. Stevens System of Leverage 287 LIST OF ILLUSTRATIONS. Fig. 109. Hodge System of Leverage 287 Fig. 110. Leverage System for Tenders 287 Fig. 111. American Driver — Brake Leverage 289 Fig. 112. Showing Markings on Air-Hose 295 Fig. 113. Method of Testing Hose 297 Fig. 114. Water Brake on Simple Engine 301 Fig. 115. Baldwin Water Brake for Compound Engines — Side View 303 Fig. 116. Baldwin Water Brake for Compound Engines — Front View 304 Fig. 117. Air-Brake Recording Gauge — Revolving Type..... 308 AIR-BRAKE CATECHISM CHAPTER I. BEGINNINGS OF THE AIR BRAKE Q. What is an air brake? A. A brake operated by compressed air. Q. What was the first form of air brake used? A. The straight air brake. Q. By whom and when was it invented? A. By George Westinghouse, in 1868. Q. What forms of brake did it supplant? A. The hand and the spring brakes. Q. What parts were necessary to operate the straight air brake? A. An air pump, main reservoir, a valve called the three- way cock used to control the application and release of the brakes, a brake pipe, and brake cylinders. Q. What parts were on the engine? A. A main reservoir, pump, and engineer's valve. Q= What parts were on the car? A. The brake pipe and cylinder. Q. Where was the braking power stored with this system? A. In the main reservoir on the engine. Q. How were the brakes applied? A. By changing the position of the three-way cock on the 18 Air-Brake Catechism engine so as to allow the main reservoir pressure to flow into the brake pipe. The brake pipe, connected directly with the brake cylinder, allowed air to pass into the cylinder, forcing the piston out and applying the brake. Q. Why was this brake unsatisfactory? A. For several reasons. First, the tendency of the brakes was to apply first at the head end of the train. If they were applied suddenly the slack running ahead would cause severe shocks and damage. Second, if a hose burst in the train, the brakes could not be set with air, as it would pass out through the burst hose to the atmosphere. Third, on a long train the main-reservoir pressure would equalize with that in the brake- pipe and brake cylinders at a low pressure on account of the large space to be filled; before the brakes were fully set the engineer would have to allow the pump to compress air into the brake pipe, and brake cylinders, and before maximum braking power was obtained the train would be stopped. Fourth, the effect of friction on the flow of air from the main reservoir through a long train made this brake apj)]y much slower. Q. What was the next form after the straight air brake? A. The plain automatic. Q. By whom and when was it invented? A. By George Westinghouse, in 1873. Q. What brake followed the plain-automatic brake? A. The quick-action brake, which almost immediately su- perseded the plain-automatic brake in passenger service, and did very quickly in freight service. With this improved ap- paratus the brake on the last of a fifty-car train could, if so desired, be applied in two and one-half seconds from the move- ment of the brake valve handle on the engine. Beginnings of the Air Brake 19 Q. Is the quick-action brake still in use? A. Yes; all passenger and freight cars are now equipped with this brake, but at present a modified form is in general use in passenger, mail and express service. The modified form is known as the high-speed brake, the operation of which is described in another part of this book. Q. Have any modifications in the general equipment of the quick-action brake been made in freight service? A. Not in the car equipment itself aside from the addition of the retaining valve, and the modification of certain details to render the apparatus more effective for conditions now existing. Q. What changes have been made in the engine equip- ment? A. The engine equipment has been gradually developed to meet modern conditions. The modifications include double- pressure control apparatus, commonly known as schedule TJ, the duplex method of main reservoir regulation, and the com- bined automatic and straight-air brake, all of which are il- lustrated and described in detail in other parts of this book. Within the past three years, a complete and new engine, freight and passenger car equipment has been developed by the Westinghouse company. Q. What else has been developed along wth the air- brake apparatus used in passenger service? A. The air signal system. Q. What gains over the hand brake are made with the air brake? A. With a train of fifty modern equipped air-brake cars, a full and harder set brake is obtained on the entire train more quickly than a hand brake can be set on one car. Since trains handled on heavy grades have to be slowed down for the purpose of recharging, by this means the wheels are given 20 Aie-Beake Catechism a chance to cool. With the hand brakes used on heavy grades, the shoes grind against the wheels down nearly, or quite all the grade so that often the train is wrecked because the wheels are heated to so high a temperature that they break, especially where only part of the brakes are used, or where the efficiency varies greatly. Air brakes give us an increased speed of trains with greater safety. CHAPTEK II. THE WESTINGHOUSE TRIPLE VALVES Q. Where was the difference in. the car equipment be- tween the straight-air and automatic brake made? A. Besides the brake pipe and brake cylinder, a plain triple and an auxiliary reservoir were added to the car. Q. With the cars equipped with the automatic brake, what gain was made over the straight-air brake? A. (1) The necessary braking power for each car, regard- less of the length of the train, was stored in the auxiliary reservoir under that car, so that the brakes could be fully set very quickly, as compared with the action of the straight-air brake. (2) If the train broke in two or a hose burst, the triples would automatically apply the brakes; whereas with the straight-air the brakes could not be applied. Q. What was the essential feature of the automatic brake? A. The plain triple valve. Q. Where was it located? A. On the car, at the junction of the brake pipe, auxiliary reservoir, and brake cylinder. Q. Did the pump and three-way cock remain on the engine? A. Yes ; this was left for later development. THE PLAIN TKIPLE VALVE. Q. In the study of the triple valve what is the main thing to be borne in mind in order to understand its oper- 22 Air-Brake Catechism ation and its probable action under the many and varied conditions which are encountered in actual service? A. In the study of the triple valve, as well as almost any other part of the air-brake or air-signal apparatus, a clearer understanding will result if one starts at a problem by first asking himself the question, Which is the greater or controll- ing pressure acting on the part under consideration? With this point thoroughly understood the resultant action of the parts in question can be readily traced ; for instance, if a brake is applied, and there is a leak in the auxiliary reservoir, we know that this will have the effect of lowering the pressure on one side of the triple piston. We then know that the tendency will be for the piston to move away from the greater brake pipe pressure, and, as will be explained later, this effect will cause the release of the brake in question. Q. Name the different parts of the plain triple valve, Figs. 1 to 4. A. 13 and 15 are the cut-out cock and the handle; 8, the graduating post; 9, the graduating spring; m and n are feed ports; 5 is the triple piston; 6, the slide valve; 7 is the grad- uating valve which works inside the slide valve; 12, a piston- packing ring; 18, slide-valve spring; Y, the port leading to the auxiliary reservoir; X leads to brake cylinder; W leads to brake-pipe pressure. Q. For what are valve 13 and handle 15 used? A. They permit the triple to be used with the straight air- brake, automatic brake, or cut out entirely, as illustrated by the cut (Fig. 1). Q. What three positions has the handle 15 (Fig. 1)? A. As shown in the cut, by the different positions of the handle: so that the triple would be cut in, as it is with the handle 15 at right angles to the triple; pointing straight down, in which case, air coming in at W from the brake pipe would Plain Triple Valve 23 go through port e of the plugeoek 13 and out into the brake cylinder through X; or the handle could stand at an angle of 45 °, in which position ports f, a and d would all be blanked. In the first position the triple is cut in for automatic^ in Fig. 1. — Old Style Plain Triple Valve, Release Position. the second for straight air, and in the third the triple is cut out entirely. Q. Can the modern plain triple now sent out be cut into straight air? A. No. 24 Air-Beake Catechism Q. Why not? A. Because, as shown in Figs. 2, 3 and 4, the handle 15 and plug 13 are no longer used. The cut-out cock is now placed in the crossover pipe. Q. Why was it necessary to have it so arranged that it could be cut in as straight air? A. When the brakes were gradually being changed from straight air to automatic, it sometimes happened that only a few cars in the train had the triple applied. In this case the handle 15 was turned so as to cut the car into straight air to be used with the other straight-air cars. Q. Of what use are 8 and 9 (Fig. 1)? A. In applying the brakes, when piston 5 moves out and touches the stem 8, held by the graduating spring 9, (Fig. 1), the piston is stopped, if a gradual reduction is being made in the brake-pipe, when the piston has drawn the slide valve down far enough to make a port connection between the au- xiliary and cylinder. Q. If a quick reduction is being made in the brake- pipe, will the spring 9 stop the triple piston? A. No; a quick reduction causes the triple piston 5 to move down quickly, and the sudden impact compresses the spring 9, allowing the piston 5 to move down until it strikes gasket 11, to what is known as emergency position. Q. 5 (Fig. 1) is called the triple piston. How is it actuated? ' A. Brake-pipe pressure is on the lower side of the piston and auxiliary pressure on the upper or slide-valve side. It is by changing these pressures that the piston is moved. Q. What are the duties of the piston as it moves? A. To open and close the feed ports m and n (Fig. 1) through which the brake-pipe pressure flows into the auxil- Plain Triple Valve 25 iary reservior, to move the graduating- valve 7 and the slide valve 6. Q. What is the duty of the graduating valve 7 (Fig. 1)? TO AUXILIARY REE '/2 PIPE TAP TO TRAIN LINtJ Fig. 2. — Plain Triple Valve, Service Position. A. It is the small valve inside the slide valve, and its duty as it is moved downward and upward by the triple piston is to open and close the port p through which, in the 26 Air-Brake Catechism service application, auxiliary-reservoir pressure flows to the brake cylinder. Q. Does the graduating valve move every time the triple piston moves? 1/S PIPE TAP AKE CYLINDER 1/2 PIPE TAP rO AUXILIARY RESERVOIR Vi PIPE TAP TO TRAIN (.INS Fig. 3. — Plain Triple Valve, Lap Position. A. Yes. because it is fastened to the stem of the piston by a pin which passes through both the graduating valve and the stem of the triple piston. The pin is represented by Plain Triple Valve 27 the dotted lines running through the lower end of the graduating valve at right angles to it. Q. Could we get along without the graduating valve? A. Yes, but the sensitiveness of the triple would be de- stroyed. Q. How does the graduating valve make the triple sensitive? A. A reduction of brake-pipe pressure causes the triple to assume service position, and after the auxiliary pressure lias expanded to a trifle below that in the brake-pipe, piston 5 (Fig. 3), moves up and closes the graduating valve on its seat. Brake-pipe pressure had simply to overcome the fric- tion on the triple piston-packing ring to do this, but had we no graduating valve the brake-pipe pressure would have had to be strong enough to overcome the additional friction of the slide valve to move it back far enough to close port p. When wishing to apply brakes harder, a heavier reduction would be necessary to again move the slide valve to service position. By the use of the graduating valve, the slide valve is moved to service position with the first reduction, where it remains until the brake is released or in case the emergency is used. Q. What are the duties of the slide valve? A. In the plain triple, when moved by the triple piston, it serves to make a connection between the auxiliary-reservoir and the brake cylinder or between the brake cylinder and the atmosphere. Q. Does the slide valve move every time the piston moves? A. No; the slide valve will not move when the piston starts down until it has moved far enough for the lug just above 18 (Fig. 1) to strike the valve. Also, if the piston is down full stroke : when it starts back the slide valve will 28 Air-Brake Catechism not move until the piston has gone back far enough to seat the graduating valve. Q. Of what use is the spring 18, Fig. 1? A. Its duty is to hold the slide valve on its seat and to prevent dirt from collecting there when there is no auxiliary- reservoir pressure to hold the valve on its seat, as when the car is "dry." Q. What is the difference in the four triple valves shown in Figs. 1, 2, 3, and 4. A. They are all plain triple valves, but the one showing release position is the older type which could be cut into straight air. The other three represent the modern valve which is cut out or in by means of a cutout cock placed in the cross-over pipe between the drain cup and triple valve. FUNCTIONS OF THE TEIPLE VALVE IN THE OPERATION OF THE BRAKE. Q. Why is this valve called the triple valve? A. Because it automatically does three things : charges the auxiliary-reservoir, applies the brake, and releases it. Q. If an engine couples to a car that is not charged, how does the triple charge the auxiliary reservoir on the car when the hose is coupled and the angle cocks turned so as to allow the compressed air to flow into the brake- pipe on this car from the engine? A. A cross-over pipe from the brake-pipe couples to the triple at W (Fig. 1.) The pressure from the brake-pipe passes into the triple at W, through port c as indicated by the arrow into cavity B; thence through the feed ports m and n into the chamber where the slide valve moves and out into the auxil- iary-reservoir at Y. Functions of the Triple Valve 29 Q. How long does the air continue to flow into the auxiliary reservoir? A. Just as long as the brake-pipe pressure is greater than that in the auxiliary, that is, until the pressures are equal on the two sides of the triple piston 5. Q. How are the two sides of the piston referred to? A. The lower side, having pressure on it, is called the brake-pij3e side of the piston, and the upper side, having aux- ilary-reservoir pressure on it, the auxiliary or slide-valve side. Q. What is necessary to cause piston 5 (Fig. 1) to move from release position? A. Any reduction of brake-pipe pressure; a break in the hose; the use of his valve by the engineer to make a brake- pipe reduction. Q. If a reduction of brake-pipe pressure is made, how does the triple respond? A. Auxiliary-reservoir pressure now being greater forces the triple piston down. Q. What two things does the piston do when it starts to move down? A. It closes the feed grooves m and n and moves the grad- uating valve from its seat. Q. Does the slide valve move as soon as the piston? A. No, not until the lug above 18 (Fig. 1) is drawn down far enough to rest against the slide valve. Q. What does the slide valve do as soon as the lug strikes and moves it down? A. It first closes the exhaust port g which in release posi- tion connected the brake cylinder with the atmosphere through X, d, e, f, g, h and &. 30 Atr-Beake Catechism Q. How far down does the triple piston travel? A. Until the projecting stem of the piston strikes the stem 8 held by the graduating spring 9 (Fig. 2). X V4 PIPE TAP TO BRAKE CYLINDER l/ 2 ' PIPE TAP 70 AUXILIARY RESERVOIR p IG 4.— Plain Triple Valve, Emergency Position. Q. When these stems touch, how does the slide valve stand? A. Port p of the slide valve is in front of port /, and. as the graduating valve was pulled from its seat when the pis- Functions of the Triple Valve 31 ton first moved, the auxiliary-reservoir pressure is now free to pass into the slide valve through port Z, called the service or graduating port, which leads into port p. The air passes throught ports Z, p, p, f, f, and out throught X to the brake cylinder. Q. How long does the graduating valve remain off its seat so as to allow auxiliary reservoir pressure to flow to the brake cylinder? A. We reduced the brake-pipe pressure to allow the greater auxiliary-reservoir pressure to move the piston clown and open the service or graduating port p between the auxiliary and cylinder. Just as long as the auxiliary pressure is greater, the piston will stay down and the graduating valve remain un- seated. As the auxiliary pressure expands into the brake cylinder it gradually becomes less until, when the brake-pipe pressure becomes enough greater than that in the auxiliary to overcome the friction on the packing ring 12 (Fig. 3), the pis- ton automatically moves back and seats the graduating valve. Q. Does the slide valve move? A. No, not now. Q. Why not? A. The brake-pipe pressure was just strong enough to over- come the friction on the packing ring 12, move the piston back, and close the graduating valve. With the ports all closed, the piston would also have to compress the air in the auxiliary to go back any farther. Then, too, the pressure left in the auxiliary-reservoir, acting to force the slide valve on its seat produces a friction, if the valve were moved that the brake-pipe pressure as it stands is not sufficiently strong to overcome. Q. How do the auxiliary reservoir and brake-pipe pres- sures now stand? A. Practically equal although the auxiliary pressure had 32 Air-Brake Catechism to be a trifle less to allow the triple piston to be moved back sufficiently to seat the graduating valve. Q. The brake is now partially applied and the triple is on what is termed lap position; what must be done to apply the brake harder? > A. Another reduction of brake-pipe pressure must be made. Q. How does this set the brake tighter? A. The auxiliary pressure once more being greater than that in the brake-pipe forces the triple piston down until it is again stopped by the graduating post. This movement is just sufficient to unseat the graduating valve the slide valve remaining where it was with its service port p (Fig. 2) in front of that to the brake cylinder. About the same amount of air pressure passes from the auxiliary to the cylinder that was taken from the brake-pipe and the piston once more hav- ing a trifle more pressure on the brake-pipe than on the auxil- iary side moves back sufficiently to seat the graduating valve. Q. How long can these brake-pipe reductions continue to be made and cause the brake to set harder? A. Until the pressures have finally equalized between the auxiliary-reservoir and the brake cylinder. Q. After the auxiliary and brake-cylinder pressures were equal, would the brake set any harder if all brake- pipe pressure were allowed to escape to the atmosphere? A. No; when the brakes are fully set the auxiliary-reser- voir and brake-cylinder pressures are equal, and a further re- duction of brake-pipe pressure would only be a waste of air that the pump would have to replace to release the brakes. Q. If a further brake-pipe reduction were made after the brake was fully set, would piston 5 (Fig. 1) move any farther than until the piston and graduating post touched? A. Yes; the spring 9 could not withstand the auxiliary- Functions of the Triple Valve 33 reservoir pressure, as it is so much in excess of the reduced brake-pipe pressure, and the piston would move down until it seated on gasket 11. In this position there would be a direct connection by the end of the slide valve between the auxiliary- reservoir and brake cylinder, but the brake would not set any tighter, as the auxiliary-reservoir, and brake-cylinder pres- sures were already equal. Q. The brake is now fully set. What is necessary to release it? A. It is necessary to get the pressure on the brake-pipe side of the triple piston greater than that on its auxiliary-reser- voir side. Q. How is this done? A. By moving the handle of the engineer's valve so as to connect the pressure, stored in the large main reservoir on the engine, with the brake-pipe. Air flowing from the main res- ervoir into the brake-pipe causes the pressure on the side of the triple piston to be sufficiently strong to overcome auxilary- reservoir pressure and force the triple piston to release posi- tion. Q. When the triple is forced to release position the slide and graduating valves are carried with it. What two port openings are made in this position? A. One between the brake-pipe and auxiliary-reservoir through the feed ports m and n (Fig. 1) ; and one from the brake cylinder to the atmosphere through ports d, e, f, g, h and Tc. The triple is in release as shown in the cut. Q. We notice that the feed grooves m and n (Fig. 1) are very small. How long would it take to charge an auxiliary reservoir from zero to seventy pounds with a constant pressure of seventy pounds in the brake-pipe, using the triple now sent out? A. About seventy seconds ; and occasionally a little longer. 34 Air-Brake Catechism Q. Will it charge more quickly than this with a greater pressure than seventy pounds in the brake-pipe? A. Yes. Q. Had we a train of fifteen cars, could we charge the fifteen auxiliary reservoirs as fast as we could one? A. No, because we now have fifteen feed grooves in the triples drawing air from the brake-pipe, and the pump cannot compress air fast enough to keep the brake-pipe pressure at seventy pounds. Q. Why not make these feed grooves larger so as to charge the auxiliary reservoirs more quickly? A. The purpose is to make the grooves sufficiently small that on a long train the auxiliaries will charge as nearly as possible alike. On a long train there is a tendency for the head auxiliaries to charge much faster than the rear ones, if the triple feed grooves are larger than those now used. Q. What is likely to happen if some auxiliary reser- voirs charge faster than others? A. As the air is fed from the main reservoir back into the brake-pipe until those pressures are equal, and as the pump will not, on a long train, supply air as fast as the triple feed grooves take it from the brake-pipe, it follows that the auxil- iaries which charge the slower will continue to feed from the brake-pipe and cause a reduction that will set some of the head brakes. Q. So far we have spoken of the action of the plain triple only in the service application. What is the differ- ence in the action between the service and the emergency? A. In service the brakes set gradually, while in emergency they go on very suddenly. Q. A gradual reduction sets the brakes in service. Functions of the Triple Valve 35 What kind of a reduction is necessary to set the brakes in emergency? A. A sudden reduction. Q. Describe the emergency action of the plain triple. A. The suddenness of the brake-pipe reduction causes piston 5 (Fig. 4) to move down suddenly, striking the stem 8 a quick, sharp blow which the graduating spring 9 is not stiff enough to withstand. The piston travels down full stroke and bottoms on gasket 11. This is emergency position, and the slide valve has been drawn down so that, air coming through Y from the auxiliary-reservoir passes by the end of the slide valve directly into the large port / leading to the brake cylinder without first going through the small service port p in the slide valve, as it did in the service position. Q. Why does the brake set more quickly? A. Because the air goes directly to the cylinder through a larger port than is used in service. Q. Do we gain any more pressure with the plain triple in emergency than in full service? A. No ; in both cases the auxiliary-reservoir pressure equal- izes with that in the brake cylinder, but in emergency these pressures equalize more quickly because of the air reaching the brake cylinder through a larger port. Q. Are plain triples still used? A. Yes, but they are used almost entirely on engines and tenders. Their use on cars is confined principally to a very few of those equipments put on before the quick-action triple was introduced. Q. Where triples are used, is a plain triple valve always used on tenders? A. No; the present practice is to use a plain triple valve on the tenders of freight and switch engines; on the tenders 36 Air-Brake Catechism of passenger engines a quick-action triple valve is being used more generally. Q. What has led to the use of a quick-action valve on passenger-engine tenders? A. The general introduction of the high-speed brake in passenger, mail, and express service is responsible for this practice having become general, although some roads have been using quick-action triples on their tenders in both freight and passenger service for some time. The quick-action triple on the tender is especially desired to help carry a sud- den reduction through the second engine in an emergency ap- plication when double-heading. Q. Is present equipment being fitted with plain or quick-action triple valves. A. Neither, the ET engine and tender equipment is being almoct exclusively applied. QUICK ACTION TRIPLE YALYEu Q. When and by whom was the quick-action triple invented? A. In 1887, by George Westinghouse. Q. We have already had the plain triple valve. Why was the quick-action triple valve necessary? A. The plain triple valve was satisfactory so long as only the service application was used, but not so with the emer- gency application on a long train. In this latter case the head brakes were fully set so much sooner than those on the rear, that the slack of the train ran ahead and often did great damage. Q. What two important advantages are gained by the quick-action triple valve? A. We are enabled by the quick-action feature to set the 'ig. 4 a. The Old Standard Quick-Action Triple Valve. Release and Charging Position. — Quick-Action Triple Valve 37 brakes throughout the train before the slack has a chance to run ahead and do damage, and not only does the brake set more quickly in emergency, but it is also set harder, thus per- mitting a quicker stop and a higher safe speed for trains. tO TRAIN PlPf «"p|P£ TAP Fig. 5.— Quick- Action Triple Valve, Release Position. Q. In the use of the service application, what is the difference between the action of the plain and the quick- action triples? 38 Air-Brake Catechism A. None whatever; their action and the parts employed are identical, excepting the additional ports placed in the slide valve of the quick-action triple, which are used only in emergency. TO TRAIN PIPE 1 PIPE TAP Fig. 6. — Quick-Action Teiple Valve, Service Position. Q. Will these two kinds of triples scattered through a train work together properly in service? A. Perfectly. Quick-Action Triple Valve 39 Q. Name the different parts of the quick-action triple not found in the plain triple. A. The strainer 16 (Fig. 5). The additional port TO TRA N PIPE I PIPE TAP Fig. 7. — Quick-Action Triple Valve, Lap Position. s in the slide valve and the removed corner of the slide valve shown in Fig. 10. 8 is the emergency piston. 10 is the emergency or, as it is more commonly called, the rubber-seated 40 Air-Brake Catechism valve. 15 is called the brake-pipe check, also the emergency check. Q. Of what use is the strainer 16, Fig. 5 ? A. Strainer 16 is to keep dirt from getting into the triple in such a way as to close the small feed ports % and Jc. Q. Of what use is piston 8? A. If the triple is moved so as to allow auxiliary-reservoir pressure to get into port t on top of piston 8, this piston will be forced down, thereby forcing the emergency valve 10 from its seat. Q. What is done when the rubber-seated or emergency- Valve 10 (Fig. 8) is forced from its seat? A. All air escapes from cavity Y and allows brake-pipe pressure to force the brake-pipe check 15 from its seat. Q. Of what use is the check valve 15? A. If a hose breaks in the brake-pipe, the brakes would fully apply on the whole train and, with no air in the brake- pipe, were it not for the check valve 15, brake-cylinder pres- sure coming in at c would force valve 10 from its seat and pass directly to the brake-pipe through cavity Y and out of the broken or parted hose releasing all of the brakes. Q. Explain the action of the quick-action triple in emergency. A. A quick brake-pipe reduction causes the auxiliary pres- sure to force the triple piston out the full length of chamber h (Fig. 8), the graduating spring 22 being compressed on ac- count of its inability to withstand the sudden blow from the triple piston. With the triple piston in the extreme position to the left, or that of emergency, port s of the slide valve is in front of port r, thus establishing a connection between the auxiliary and brake cylinder. At the same time the removed corner of the slide valve, shown in Fig. 10, is in front of port t leading to the top of the emergency piston 8. The auxiliary pressure ^ Quick-Action Triple Valve 41 forcing piston 8 down unseats the emergency valve 10. This valve being unseated allows all pressure to escape from cav- ity Y. With no pressure in cavity Y to hold the brake-pipe check to its seat, the brake-pipe pressure under the check raises it and passes into cavity Y over seat of valve 10 to cav- ity X and out at c into the brake cylinder; at the same time the auxiliary pressure is entering the cylinder through port r. As soon as the pressures equalize, piston 8, valve 10, and check 15 go to their normal positions. Q. Of what use are Figs. 9 and 10? A. Fig. 10 gives a better idea of the location of the ports in the slide valve; Fig. 9, the location of the ports in the bushing inside of which the slide valve works. Q. Name the parts. A. 26 (Fig. 5) is the drain plug; 16, the brake-pipe strain- er; 20, the graduating nut; 21, the graduating stem or post; 22, the graduating spring; 4, the triple piston; j, the piston stem; % and Je, the feed ports; 6, the slide-valve spring; 3, the slide valve; 7, the graduating valve; w, the service or graduating port; n, the exhaust port; s, the emergency port; z, a continuation of the service port w; 15, the brake-pipe or emergency check; 12, the brake-pipe check spring; 10, the emergency or rubber-seated valve; 8, the emergency piston. The exhaust port p leads around outside the brass bushing to the atmosphere as shown in Fig. 9 by the dotted lines. Q. What views do Figs. 5 to 8 represent? A. The triple valve in its four positions: release, service, lap, and emergency positions. Q. We have seen that with the quick-action triple the brakes are set harder in emergency. Are brakes set in emergency any harder to release? A. They are with quick-action triples only. Q. Why? A. With the quick-action triples air from the brake-pipe 42 Air-Brake Catechism helps set the brakes in emergency, and the pressures equalize higher; therefore the brake-pipe pressure must be made high- er to overcome the auxiliary-reservoir pressure and force the f O TRAIN PIPE I WE TAP Fig. 8. — Quick-Action Triple Valte, Emergency Position. triple piston to release position. With the plain triple the pressures equalize at the same pressure as in service. Q. In Fig. 5 a packing ring 31 is shown in the emerg- . Quick-Action Triple Valve 43 ency piston. Is this ring found in all quick-action triple valves? A. It is in all modern passenger triples but not in freight valves. The small port in piston 8 is also found in pas- senger valves only. Fig. 9. — Slide Valve Bushing. Q. After a partial service application has been made, can we get the quick-action? A. This depends on the amount of reduction that has been made in service and upon the piston travel. In no case can we gain as much after making even a small service re- duction as we could if the sudden reduction were made when the auxiliary-reservoirs were fully charged and the brakes released. Fig. 10. — Slide Valve. After a light reduction a gain over the pressure obtained in full service can be made by going to emergency position if the piston travel is a fair length, but not with short travel. !By using the emergency after a partial service applica- 44 Air-Brake Catechism tion, even we made no gain of pressure, we would get the full service more quickly. Q. How quick must a reduction be made in the brake pipe to throw a triple into quick-action? A. Faster than the auxiliary-reservoir pressure can get to the brake cylinder through the service port in the slide valve. In this case the graduating spring will not hold the triple piston from traveling full stroke. Q. When a triple is thrown into quick-action which pressure, auxiliary reservoir or brake pipe, reaches the brake cylinder first? A. Just a flash of auxiliary-reservoir pressure reaches the cylinder as the service port in the slide valve passes the port leading to the cylinder, but the air from the brake-pipe reaches the cylinder first in any considerable volume, as the corner cut off from the slide valve allows the auxiliary-reservoir pres- sure to strike piston 8 and force the rubber-seated valve 10 from its seat before port s comes in front of port r. Q. Why is port s (Figs. 8 and 10), used in emergency, made smaller than port z, used in service, to let auxiliary reservoir pressure into the brake cylinder? A. So as to hold the auxiliary-reservoir pressure back in emergency and allow as much air as possible to enter the brake cylinder from the brake-pipe. Peculiarities and Troubles of the Quick-Action Triple Yalve. From what follows it may seem that a triple will get out of order under the slightest provocation. This, however, is not true; it is a constant source of wonder to see the fine action of triple valves which have little or poor care. A triple needs Quick-Action Triple Valve 45 no more care than any other piece of mechanism to keep it doing first-class work. The aim of what follows is to bring out its possibilities. Q. What could wholly or partially stop the charging of an auxiliary reservoir? A. The strainer in the brake-pipe where the cross-over pipe leading to the triple joins the main brake-pipe, or the strainer 16 in the triple (Fig. 5) being filled with dirt, scale, cinders or oil. Port i or h might be plugged, the triple might be cut out, or there might be a leak in the auxiliary-reservoir which let the air out as fast as it came in. Q. If all auxiliary reservoirs did not charge equally fast, what would be the effect? A. If we wished to apply the brakes very soon, the ones with the auxiliary-reservoirs not fully charged would not re- spond to the first reduction if light. Q. Occasionally after coupling up the hose in a train it is found that the brake on a car will not apply in re- sponse to a reduction of brake-pipe pressure. What might be the trouble other than those just described? A. It sometimes happens that the switch crew is respon- sible for such an occurrence. Sometimes when an air train is brought into a yard and the yard crew is in a hurry to "drill" the train with an engine not equipped with air, they do not always bleed the train in the proper manner. In- stead of opening an angle cock and then bleeding all the reservoirs by hand, they put a piece of coal or wood under an arm of the auxiliary-reservoir release valve to do the work of holding the valve from its seat. In this way they save time for themselves but are a source of considerable bother to the ones who inspect the train. On account of the air escaping through a comparatively large port, the leakage is not always detected without a careful examination. 46 Air-Brake Catechism Q. Will any other trouble result from the strainers being corroded or dirty? A. Yes ; we might not be able to make a sufficiently quick reduction on the triple piston to get quick-action. Q. One triple going into quick-action makes a sud- den brake-pipe reduction which starts the next triple, and that one the next, and so on throughout the train. If five or six cars together in the train were cut out, or had plain triples, or very dirty strainers, would the triples back of these go into quick-action when the engineer made a sudden reduction? A. No, on account of the resistance of friction to the pas- sage of the sudden reduction through the six car lengths of pipe. The friction gradually destroys the suddenness of the reduction, and there is only a slight and gradual reduction, in the brake-pipe back of the cars cut out. Q. What bad effect would follow if the engineer did not continue making a reduction? A. The air coming ahead from the back of the train would release the head brakes. Q. Could these brakes in the back of the train be ap- plied? A. Yes, in service but not in emergency. Q. Water sometimes collects in cavity 13 (Fig. 5) of the triple. Where does it come from? A. It comes into the brake-pipe as vapor in the air, and condenses whenever a sudden drop in brake-pipe pressure oc- curs. Q. What bad effect will water have in this place? A. It is likely to freeze in winter and block the flow of air through the triple. Q. What should be done in such a case? A. Apply burning waste and when thawed remove the Quick-Action Triple Valve 47 drain plug 26 to remove the water or the trouble will recur. Q. What would be the effect of a weak or broken graduating spring? A. We would have nothing to stop the triple piston when it reached service position, and it would move on to emergency position. Q. If one triple goes into quick-action, will the rest go? A. Yes, as a sudden reduction is made on the brake-pipe through the emergency ports of the triple in this case. This sudden reduction starts the next and that the next and so on. Q. Will a weak or broken graduating spring always throw the triples into quick-action? A. No, only on a short train. Q. Why not on a long train? A. On a short train, with a gradual brake-pipe reduction, air is drawn from the brake-pipe faster than the auxiliary reservoir pressure can get to the brake cylinder through the service port of the slide valve. When the auxiliary-reser- voir pressure is enough greater than that in the brake-pipe, it forces the triple piston to emergency position, as there is no graduating spring to stop it. On a long train, it takes longer to make a corresponding reduction on account of the larger volume of air in the brake- pipe. This gives the auxiliary-reservoir pressure longer to pass into the cylinder, and as a result the brake-pipe and auxiliary-reservoir pressures keep about equal and the triple piston will not move to emergency position unless a sudden reduction is made. Q. How many air cars must there be in a train so that a broken or weak graduating spring will not affect the service application? A. Usually not less than six or seven; with more than this number, if otherwise the triples work properly, the grad- 48 Air-Brake Catechism uating springs could be removed from all triples and no bad effect be noticed. Q. What two things will cause the triples to go into quick-action regardless of the length of the train? A. A sticky triple or a broken graduating-valve pin. (The one which fastens the graduating valve to the piston stem as shown by the dotted lines, Fig. 5.) Q. Why will a sticky triple throw the brakes into emergency? A. Because the triple does not respond to a light reduc- tion. When it does move it jumps, and the sudden blow compresses the graduating spring and the triple is in the quick-action position. This car starts the rest as before explained. Q. Why will a broken graduating pin throw the brakes into emergency? A. Because with this pin broken there is nothing to move, the graduating valve from its seat when the triple piston moves and the auxiliary-reservoir pressure is acting to hold it on its seat. When a brake-pipe reduction is made and the triple assumes service position, no air can leave the auxil- iary-reservoir and pass through the graduating or service port of the slide valve, as the graduating valve is on its seat. When sufficient brake-pipe reduction has been made so that the graduating spring cannot withstand the auxiliary-reservoir pressure acting on the piston, the triple goes to the quick- action position, and we get the quick-action on this car and consequently on the rest as before explained. Q. Which of these three troubles — weak graduating spring, broken graduating pin or sticky triple — will usually be found to exist if the brakes go into emergency with a service reduction? A. A sticky triple, and this usually means that the triple causing the trouble has had poor care. Quick-Action Triple Valve 49 Q. Shall we get the same result regardless of the loca- tion of the faulty triple in the train? A. Yes; if one starts, all do. Q. What is the probable trouble with a brake which, when set in service, will sometimes remain set and some- times release? A. A dirty slide valve which sometimes seats properly and at others not; in the latter case auxiliary-reservoir pressure escapes to the atmosphere through the exhaust port and al- lows brake-pipe pressure to force this triple to release position. Q. How may this defect be remedied? A. Eemove the triple piston and attached parts, clean care- fully, loosen the packing ring without removing and rub a little oil on the slide valve with the finger. Q. Why not pour on the oil? A. Too much oil is bad, as it collects dust, which with the oil forms gum. This causes a triple to stick. Q. What effect will a moderate leak in the brake pipe have if the brakes are not set? A. It will simply cause the pump extra work to supply it. Q. What effect if the brakes are set? A. It will cause them to apply harder. Q. Will the leak cause only the brake on that car to leak on, or all? A. All, as the brake-pipe is continuous through the train. Q. What effect will a leak in an auxiliary reservoir have if a brake is released? A. It will keep the pump at work the same as a brake-pipe leak. Q. What effect if the brakes are applied? A. It will leak the brake off on the car where the leak is and, then, drawing air from the brake-pipe through the feed ports, it will gradually set the other brakes tighter. 50 Air-Brake Catechism Q. There are a number of leaks in the triple which will cause a blow at its exhaust port. Name the two most likely to produce this effect. A. A leaky slide valve or a leaky rubber-seated valve (Fig. 5). Q. How can we tell which of these is causing the trouble? A. As the exhaust port in the slide-valve seat is always in communication with the atmosphere, whether the brakes are applied or released, a leak by the face of the slide valve will cause a constant blow. Q. How else can we tell if it is the slide valve that causes the trouble? A. Apply the brake, and if auxiliary-reservoir pressure is leaking away under the slide valve, the brake will generally release. Q. How can we tell if the trouble is with the rubber- seated valve? A. The rubber-seated valve will cause a blow at the ex- haust only when the brake is released. Q. Why? A. The rubber-seated valve 10 (Fig. 5) leaking will allow the pressure to leave cavity Y. The brake-pipe pressure then raises check 15 and passes through cavity Y past the rubber- seated valve, through cavity x, ports c and r, into the exhaust cavity n of the slide valve and out to the atmosphere through port p. When the brake is applied, port n in the slide valve is closed to port r, consequently the blow stops. Q. Where does the air which is leaking past the rub- ber-seated valve go after the brake is applied? A. Direct to the brake cylinder through c, and this brake continues to set harder. Quick-Action Triple Valve 51 Q. Why is a leaky rubber-seated valve more likely to slide the wheels on a car in a long train than in a short one? A. After the brakes are applied, this leak allows the brake- pipe and brake-cylinder pressures to equalize. With a long brake-pipe there is a much greater volume of air, and these pressures will equalize higher. Q. How else can we tell if the rubber-seated valve leaks? A. Turn the cut-out cock in the cross-over pipe from the brake-pipe to the triple after everything is charged: if the rubber-seated valve leaks, it will draw air from the brake- pipe ; with the cut-out cock closed, this leak is not being sup- plied, and the reduction will cause the brake on this car to apply. Q. Give another symptom which indicates a leaky rub- ber-seated valve. A. The leak above the check 15 caused the check to rise to supply it, and when the cavity is again charged the check closes. It sometimes rises and closes so fast as to make a loud buzzing sound. Q. What is usually the cause of leaking 1 in a rubber- seated valve? A. Dirt on the seat, a poor seat caused by wear, the use of oil on the quick-action part of the triple, or using too much oil in the brake cylinder, which will work into the triple and cause the rubber to decay. Q. If dirt is the source of the trouble, how may it be removed without taking the triple apart? A. Set the brake by opening the angle cock after closing the cock at the other end of the car. If there is dirt on the valve, it may be blown off in this way. 52 Air-Brake Catechism Q. What besides the slide and rubber-seated valves will cause a blow at the exhaust port of the triple? A. Gasket 14 (Fig. 5) leaking between e and cavity X, or the gasket leaking between the brake cylinder and auxil- iary-reservoir where the triple is bolted to the cylinder. On freight equipments there is a pipe which runs inside the auxiliary to the brake cylinder; this pipe leaking will also cause a blow. Q. Are these leaks common? A. On the contrary they are very uncommon. The blow is almost invariably due to a leaky slide or emergency valve. Q. What effect would the leaking of graduating valve 7 (Fig. 5) have? A. The action produced by such a leak is uncertain, and depends greatly on the conditions connected with it. When the brake is applied, the triple assumes lap position after the auxiliary-reservoir pressure is a trifle less than that in the brake-pipe. If the graduating valve leaks, the auxiliary-res- ervoir pressure gradually reduces, and the brake-pipe pressure forces the triple piston and slide valve back until the blank on the face of the slide valve between ports z and n is in front of port r. If the graduating valve does leak, no more air can leave port z in this position, and the slide valve stops. This blank space is only a trifle wider than port r, so if the valve is in good condition and works smoothly, the brake should not release; but if it works hard, it is likely to jump a little when it moves, and open the exhaust port. Q, Give a rule by which to tell how a leaky graduat- ing valve will act. A. If the triple is in proper condition, a leaky graduating valve should not release a brake. If the triple is a trifle sticky, a brake is likely to be released. A leaky slide valve or a slight auxiliary-reservoir leak in combination with a leaking Type "K" Triple Valve 53 graduating valve will release a brake. The action also de- pends upon the condition of the triple-piston packing ring which if comparatively loose will permit brake-pipe pressure to feed into the auxiliary-reservoir as fast as its pressure es- capes. If brake-pipe and auxiliary-reservoir pressures remain equal, the triple piston is not affected, and the leakage by the graduating valve would not release the brake. THE TYPE "K" TRIPLE VALVE. Q. What does Fig. 11 illustrate? A. Fig. 11 illustrates the improved K triple valve which is now superseding the former quick-action triple valve in freight service. Q. Does this triple valve differ any in principle of operation from the old standard valve? A. No; it operates on the same principle, that is, a re- duction of brake-pipe pressure causes the brake to apply and an increase of brake-pipe pressure causes it to release. Q. What are the important advantages of the im- proved valve over the old? A. With the improved valve a portion of the brake-pipe air is vented to the brake cylinder in each service application ; this causes a quicker fall of pressure in the brake-pipe throughout the train and hence a quicker serial application of the brakes than is now obtained with the older form of triple. In the release of the brakes on long trains those on the front portion may be held applied until those in the rear have been released; this action causes the slack to settle in instead of stretching out, which latter action tends to break the train in two. There is also a uniform recharge feature by means of which the recharge at the head end is slowed up. This makes available a greater amount of air with which u Air-Brake Catechism to release and recharge the brakes at the rear of the train; it also does away with the overcharge of the auxiliary reser- voirs at the front of the train, which overcharge usually results in the reapplication of the brakes near the engine when the brake valve handle is moved to running position. The reapplication wastes air and overheats wheels because of extra amount of work performed. Fig. 11. — K Teiple Valve — Exterior View. Q. What other advantages are obtained with the K triple? A. There is a large saving in the quantity of air used which results in less pump labor, the brakes apply more uni- formly and with greater certainty on the longest trains and with any service reduction desired. In heavy grade work there is much less chance for the engineer to "lose his air" and of the train running away in consequence. Q. In the emergency application of the brake is there any advantage of the new triple valve over the old? A, The emergency feature of the triple has not been Type "K" Triple Valve 55 changed and the results that can be obtained with the valves are practically identical. Q. In service application using a brake-pipe pressure of 70 pounds, how much reduction is necessary to set the brakes in full? A. About 17 pounds, 3 pounds less than with the standard triple. Q. Will these triples give satisfactory results in brak- ing when intermingled in any considerable number with the older triples? Fig. 12. — K Teiple Valve- Cross Section. 56 Aie-Brake Catechism A. Yes, and on long trains they will very materially im- prove the action of the older triple. Q. What does Fig. 12 represent? A. It is a vertical cross section of the K triple representing the interior construction. Q. What are the names of the different parts of the K triple as numbered on this cut? A. 2, Valve Body; 3, Slide Valve; 4, Main Piston; 5, Main-Piston Packing Ring; 6, Slide-Valve Spring; 7, Grad- uating Valve; 8, Emergency Piston; 9, Emergency- Valve Seat; 10, Emergency Valve; 11, Emergency- Valve Rubber Seat; 12, Check- Valve Spring; 13, Check-Valve Case; 14, Check- Valve Case Gasket; 15, Check Valve; 16, Air Strain- er; 17, Union Nut; 18, Union Swivel; 19, Cylinder Cap; 20, Graduating Stem-Nut; 21, Graduating Stem; 22, Graduating Spring; 3, Cylinder-Cap Gasket; 24, Bolt and Nut; 25, Cap Screw; 26, Drain Plug; 27, Union Gasket; 28, Emergency- Valve Nut; 29, Retarded-Release Stem; 32, Retarded-Release Spring Collar; 33, Retarded-Release Spring; 34, Retarded-Re- lease Stem Pin; 35, Graduating- Valve Spring. Q. What is represented in Fig. 13? A. A face view of the graduating valve, a face view and a top view of the slide valve, and a view of the slide-valve bush, with their ports, cavities, etc., arranged as actually con- structed. Q. What is represented in Figs. 14 to 18 inclusive? A. These figures are diagrammatic drawings intended to show clearly the relation of the various ports and passages in the different operative positions of the valve. Q. Explain the operation of the triple as shown in Fig. 14. A. Full release position is shown in Fig. 14. Brake-pipe air enters the triple-valve body at the connection marked BP, Type "K" Triple Valve 57 passes upward through passage, a, e, f and g to chamber In, thence through the feed groove i past the triple piston into chamber R and out to the auxiliary reservoir. Brake-pipe air also flows past the non-return check valve, from chamber 0* FACE VIEW GRADUATING VALVE •4* FACE VIEW TOP VIEW SLIDE VALVE. b^^m^gg^ ^^^^^^^^^ SLIDE VALVEBUSH. Fig. 13. — K Triple Valve. a into chamber F, thence through passage y in the body and port j in the slide valve to chamber R and the auxiliary reser- voir. In this way the auxiliary reservoir is charged up to the pressure in the brake pipe. The slide valve is shown in this figure with its exhaust cavity n uncovering wide the exhaust 58 Air-Brake Catechism port in the slide-valve seat leading from the brake cylinder to the atmosphere, providing for the release of the brake through port r, cavity n, and port p. Q. What is shown in Fig. 15? A. In this figure, the parts of the K triple are represented in the service position, the position they assume while a serv- ice reduction in brake-pipe pressure is being made. Q. Explain the operation in service position. A. The triple piston, as shown, has moved toward the _„_: Fig. 14. — K Triple Valve — Full Release. left until it touches the graduating stem, and it has carried with it the main slide and the graduating slide valves. Port z in the main slide valve registers with port r in its seat. Port z is uncovered by the graduating valve so that air is free to flow from the auxiliary reservoir to the brake cylinder. At the same time passage y and port o are in register, and cavity v in the graduating valve spans port o and q. Port q is in reg- ister with port t leading around the loosely fitting piston to chamber x and the brake cylinder. Hence, arranged as shown, Type "K" Triple Valve 59 these ports permit brake-pipe air to flow into the brake cyl- inder at the same time that the auxiliary reservoir is supply- ing air. Q. What does Fig. 16 represent? A. It shows the triple valve in what is termed the Service- Lap position. Q. When does the triple valve assume this position? A. When the pressure in the auxiliary reservoir falls ww/MwmM Fig. 15. — K Triple Valve — Service Position. slightly below that remaining in the brake pipe. As shown in this figure the triple-valve piston has moved the graduat- ing valve back far enough to close ports o, q, and z, and thus prevent further flow of air from both the auxiliary reservoir and the brake pipe to the cylinder. It will be noted in the figure that the main slide valve is ahead of its position shown in Fig. 15. The valve would only assume this position if the brake-pipe pressure were reduced faster than the auxiliary-reservoir pressure could reduce to the brake cylinder, 60 Air-Brake Catechism otherwise port o would remain in register with port y as in Fig. 15 but the graduating valve would have closed ports o and z as shown in Fig. 16. Q. What is shown in Fig. 17? A. Fig. 17 represents the different parts of the K triple in the Ketarded-Kelease position. Q. How are they made to assume this position? A. By admitting main-reservoir air to the brake pipe fast Fig. 16. — K Triple Valve — Sertice-Lap Position. enough to increase the pressure considerably above that re- maining in the auxiliary reservoir. Q. Explain the operation in the retarded release position. A. As shown brake-pipe pressure forces the triple piston to the extreme right until it strikes against the slide-valve bush. When this occurs brake-pipe air feeds only through charging groove i and the small port I in the end of the slide- valve bush to reach the auxiliary reservoir. Type "K" Triple Valve 61 The triple-piston stem abuts against the retarded-release spring and partially compresses it. The slide valve has moved far enough over to bring the restricted port n (Fig. 13), the exhaust cavity, over exhaust port p, thus reducing very materially the size of this port, causing a slow release of the brake. In a long train this retarded release can, if de- sired, be obtained about 30 cars back in the train. Q. What is it that causes the triple piston to assume the retarded-release position? Fig. 17. — K Triple Valve — Retarded Release Position. A. To cause the piston to assume this position it is neces- sary to have the pressure on the brake-pipe side of the triple piston sufficiently in excess of that in the auxiliary reservoir to permit of the greater pressure acting on the brake-pipe side of the piston to compress the retarded-release spring. With the usual main-reservoir pressure and capacity, it is possible to compress this spring on a long train about thirty cars back. The effect of the friction due to the flow of air is to prohibit any rapid rise of brake-pipe pressure back in 62 Air-Brake Catechism the train but, as already stated, the desired differential be- tween the brake pipe and auxiliary-reservoir pressure can be obtained about thirty cars back in a 100-car train. Q. What does Fig. 18 represent? A. It represents the K triple in the Emergency position. Q. When does the valve assume this position? A. Whenever a heavy, quick reduction in brake-pipe pressure is made, as when the brake valve is quickly placed in emergency position or a hose bursts. W//AMMW/AWA Fig. 18. — K Triple Valve — Emergency Position. Q. Explain the operation in emergency position. A. It is the same as that given for the standard triple. Air is admitted to the top of the emergency piston through the large port t. This piston is forced downward, and brake- pipe pressure raises the non-return check valve, and flows quickly through ports r and C to the brake cylinder. At the same time port s in the slide valve registers with port r so that auxiliary-reservoir air can flow through this port also to the brake cylinder and will equalize with it. Type "K" Triple Valve 63. Q. How many sizes of the K triple are there? A. Two, the K-l and K-2. Q. On what size car equipment is the K-l triple used? The K-2? A. The K-l is used on eight-inch freight equipment, and the K-2 on ten-inch. Q. Can a K-l and a K-2 triple be readily substituted for the older corresponding size of quick-action triple? A. Yes, they are perfectly interchangeable on their re- spective reservoirs. Q. On a train of eighty cars will a five-pound service reduction set all the brakes? A. Yes, and a 5-pound reduction will be as effective in stopping an empty train from a speed of 20 miles per hour as a 20 -pound service reduction with the older triples. Q. Explain this. A. Because of the venting of brake-pipe air to the brake cylinder, a five-pound initial reduction insures the aplication of all brakes on the train in a much shorter time than they can be applied with any service reduction with the older triples, and also with a higher pressure than can be obtained from a 5-pound service reduction with the ordinary quick-action triple valve with which on this length of train only a com- paratively few brakes will apply. Q. Is there any difference in the internal construction of the K-l and the K-2 triples? A. In full release position, the charging takes place through the feed port i only with the K-l triple, while the feed port i in the piston bush and port j in the slide valve are both used with the K-2 valve. Port j does not exist in the K-l triple. 64 Air-Brake Catechism Q. As to care and maintenance of the K triple, do the same rules apply as to the old standard triple? A. Yes. THE TYPE "L" TRIPLE VALVE. Q. What valve is illustrated in Figs. 19 and 20? A. The Type L Triple Valve. Fig. 19.— "L" Triple Valve. Q. What kind of a triple valve is it, and in what ser- vice is it used? A. It is a new type of Quick-Action Triple Valve for use in High-Speed Passenger Service. Q. What feature does it have not found in the old standard quick-action triple valve already described? A. It has the Graduated Release, by means of which the Type "L" Triple Valve 65 brakes in the train can be partially released when desired; (2) it has the Quick-Service, by means of which service ap- plications are obtained throughout long trains in much less time than with the old standard triple; (3) it has the Quick- Kecharge, by means of which the auxiliary reservoirs are re- charged during release of the brakes in the same time as the air can exhaust from the brake cylinder; (4) it obtains a much Fig.- 20. — "L" Triple Valve. higher brake-cylinder pressure in emergency than with the old standard-triple valve. Q. Are the high-speed reducing valves used in connec- tion with the L Triple Valve? A. No; they are unnecessary, as the L triple performs all the duties of a triple valve and high-speed reducing valve combined. The safety valve, which is a part of the triple valve, takes the place of the high-speed reducing valve. 66 Air-Brake Catechism Q. Is any additional apparatus required when the L Triple Valve is substituted for the old standard? A. Yes, a "supplementary'' reservoir, about twice the size of an auxiliary reservoir, is required. Q. What is the purpose of the supplementary reser- voir? A. It furnishes the means of obtaining the graduated re- „^^^JL~, — Pig. 21. — Diagram of Type L Triple Valve Release and Charg- ing Position. lease, quick-recharge, and the high-emergency brake-cylinder pressure. Q. Is any other change of apparatus required when substituting the L Triple Valve? A. The brake-cylinder pressure head must be exchanged for one having all pipe connections made in it, as the L Triple is of the "pipeless" type. Type "L" Tijiple Valve 67 Q. What is the advantage of a ' ' pipeless ' ' triple valve? A. As all pipe connections are made to the cylinder pressure head, and communicate with the triple valve through suitable ports in the head and triple-valve body, the triple valve may be removed for inspection and repairs without breaking any pipe joints. Pig. 22. — Diagram of Type L Triple Valve. Quick-Service Position. Q. How does the outside appearance of the L Triple differ from the old standard? A. There is a "vent-valve" portion which lies across the top of the body at right angles to the movement of the slide- valve; and a safety valve is attached vertically to one side. Also, there is no connection for pipes on the valve. Q. What are Figs. 21 to 26. A. They are diagrams of the L Triple Valve in different 68 Air-Brake Catechism positions, with the parts so arranged as to show all the parts in one plane without regard to the actual construction of the valve. Q. Name the connections to the triple valve. A. Referring to Fig. 21, the brake pipe connects with passage a; passage C connects with the brake cylinder; port Fig. 23. — Diagram of Type L Triple Valve. Service-Lap Position. x connects with the supplementary" reservoir; the slide valve cavity R is always connected to the auxiliary reservoir. Q. How is the passenger car brake charged up at starting? A. Air flows through the brake pipe from the locomotive and enters the triple valve by passage a, e and g to cylinder li, and through the feed groove i to chamber R and the auxiliary Type "L" Triple Valve 69 reservoir ; the air also lifts check valve 15 and enters chamber Y , thence through port y in the seat and / in the slide valve, it flows to chamber R and the auxiliary reservoir; thus the latter is charged by two different channels giving a very prompt rise in the auxiliary-reservoir pressure. At the same time, air flows from chamber R through port Jc in the slide Fig. 24. -Diagram of Type L Triple Valve. Position. Pull-Service valve and x in the seat to the supplementary reservoir charg- ing it at the same time to the auxiliary-reservoir pressure. The charging continues till both reservoirs and brake pipe are at the same pressure. Q. What happens in the triple valve when a moderate service reduction takes place? A. The reduction in brake-pipe pressure in cylinder h allows the higher pressure remaining in the chamber R to force 70 Air-Brake Catechism the piston, graduating valve and slide valve to the left (Fig. 22) until the piston strikes the graduating sleeve 21, held in its place by graduating spring 22. Port y in the valve seat connects with port o in the slide valve, and the latter through a small cavity in the graduating valve, and port in the slide valve with cavity q, the latter connecting with port r and the Fig. 25. — Diagram of Type L Triple Valve. Position. Release-Lap brake cylinder. Consequently brake-pipe air lifts the check valve 15, and flows through cavity Y, port y and the connec- tions just mentioned to the brake cylinder. Not a large quan- tity of air, however, flows through this channel, for the reason that port z in the slide valve partially registers with port r in the seat, allowing auxiliary-reservoir air also to flow to the brake cylinder; and the size of the ports between the auxiliary reservoir and brake cylinder are larger than those Type "L" Triple Valve 71 between the brake pipe and the brake cylinder,, so that the larger amount of air for setting the brakes comes from the auxiliary reservoir. The small amount of air taken from the brake pipe helps to reduce its pressure, so that the reduction passes through the train more rapidly than with the old stand- ard equipment. This is the Quick-Service feature. Fig. 26. — Diagram of Type L Triple Valve. Emergency Position. Q. What is this position called? A. Quick-service position. Q. Does the triple valve remain in this position during* the brake application? A. No. As soon as the auxiliary-reservoir pressure falls, by flowing into the brake cylinder, to a point slightly below that remaining in the brake pipe, the piston and graduating valve are forced to the right until the piston strikes the slide 72 Air-Brake Catechism valve as shown in Fig. 23. In this position, both port z and the small port connecting with cavity q are closed by the graduating valve, so that no more air can now to the brake- cylinder from either the auxiliary reservoir or the brake pipe. Q. What is this last mentioned position called? A. Service-Lap Position. Q. Why SERVICE Lap? A. Because there are two lap positions in the L Triple Valve ; the Service Lap and the Eelease Lap. Q. Are there any other ports connecting- in the Service or Lap Positions? A. Yes ; cavity q always connects port r with port b in the seat, in all service and lap positions. Port b leads to the safety valve on the side of the triple valve. Q. What is the object of this arrangement? A. So that the safety valve will protect the brake cylinder against too high pressure in all service applications. Since the trij3le valve is designed for the high-speed brake equip- ment, which employs 110-pounds pressure in brake pipe and auxiliary reservoir, it is necessary to limit the pressure in the brake cylinder to 50 pounds in service applications, as the braking power of the car is calculated for this amount; if no safety valve or reducing valve was used, the 110 pounds in the auxiliary reservoir would equalize with the brake cylinder at about 85 pounds, which in the conditions of ordinary serv- ice stops, would likely cause the wheels to slide. Q. Is there any other service position than Quick Service? A. Yes; Full Service. Q. When a service reduction is made, what determines whether the triple valve will go to Quick Service or Full Service? A. The length of the train. Type "L" Triple Valve 73 Q. How is that? A. In a short train, the volume of the brake pipe is small, and its pressure will therefore reduce more rapidly than a long train, for the same reduction at the brake valve. Con- sequently, when a service reduction is made with a short train, the fall of pressure in cylinder h of the triple valve, may be rapid enough to allow the piston, when moving to the left, to slightly compress graduating spring 22 when it strikes graduating sleeve 21, as shown in Fig. 24. In this position, port o in the slide valve does not register with port y in the scat, so that no air flows from the brake pipe to the brake cylinder, except as the ports pass each other ; at the same time, port z is wide open to port r, allowing the auxiliary-reservoir air to now more rapidly to the brake cylinder, so that its fall in pressure keeps pace with that in the brake pipe. In this way, the triple valve itself automatically cuts out the Quick-Service feature when the brake-pipe reduction is suf- ficiently rapid without it. The piston and graduating valve go to Service-Lap position after the Full Service, in exactly the same manner as after the Quick Service. Q. What occurs in the triple valve when the brakes are released? A. The increase of brake-pipe pressure causes the pressure in cylinder h on the left of the piston to increase, forcing pis- ton, slide valve and graduating valve to the position shown in Fig. 21. Port r in the seat connects through port n in the slide valve, the cavity in the graduating valve, port m in the slide valve, with port p in the seat, the latter connecting with the exhaust. Thus brake-cylinder pressure can escape to the atmosphere. At the same time the auxiliary reservoir is re- charged through the feed groove i, and through the quick- recharge ports y and ;. It is also helped to recharge by the volume of air which has been bottled up in the supplementary reservoir during the service application, which now connects 74 Air-Brake Catechism through ports x and h with chamber R. In this way, the re- charging of the auxiliary reservoir is accomplished very quickly, and constitutes the Qiiick-Kecharge feature of the triple valve. Q. What is this position called? A. Eelease and Charging position. Q. How does the triple valve operate when a Gradu- ated Release is desired? A. Let us assume that the brakes were applied by a 15- pound reduction, or that brake-pipe pressure was reduced from 110 to 95 pounds. Kef erring to Fig. 23, Service-Lap position; the pressure in cylinder h on the left of the piston is 95 pounds, while that in chamber R and the auxiliary reservoir is slightly less, say 94 pounds, and the pressure in port x and the supplementary reservoir is still 110 pounds. To partally release the brakes the engineer partially reinstates brake-pipe pressure. We will say that he raises it from 95 to 100 pounds. As soon as the pressure in cylinder h rises a little, it moves the piston, slide valve and graduating valve to the release position as shown in Fig. 21. The pressure in cylinder h is now 100 pounds the auxiliary-reservoir pressure feeds up through feed groove i and ports y, j and x to 100 pounds. But the large volume of air in the supjnementary reservoir is still only slightly below 110 pounds; it therefore tends to raise the pressure in chamber R above 100 pounds by air flowing in through port x. As soon as this pressure gets a little above 100 pounds, it moves the piston and grad- uating valve again to the left until the piston strikes the slide valve, as shown in Fig. 25. Feed groove i, ports j and x are now closed, preventing the auxiliary-reservoir pressure from rising any higher; at the same time port m is closed, which stops the exhaust of brake-cylinder air through ports r, n, m and p to the atmosphere; consequently only a part Type "L" Triple Valve 75 of the brake-cylinder air escapes, and the pressure is corres- pondingly reduced, but the remaining pressure is retained. This is the Graduated Release feature. Q. Can a second graduation in release be made? A. Yes; the process just described can be repeated until the brake-pipe pressure is raised to the normal amount, and the brake-cylinder pressure completely released. Q. What is the position just described, and shown in Fig-. 25 called? A. Eelease-Lap position. Q. What occurs in the triple valve in Emergency- applications? A. The sudden reduction in brake-pipe pressure and cyl- inder h causes the piston, slide valve and graduating valve to move to the left with such force as to compress graduating spring 22, until the piston strikes the gasket at the end of the cylinder, as shown in Fig. 26. In this position, the slide valve uncovers port t in the seat and allows auxiliary-reser- voir pressure to flow to the top of emergency piston 8, forcing it downward, thereby opening emergency valve 10, and allow- ing brake-pipe air to raise check valve 15 and now rapidly through cavities Y and X to the brake cylinder. At the same time port s in the slide valve registers with port r in the seat and permits auxiliary reservoir air to flow to the brake cylin- der. When the increasing brake-cylinder pressure and the de- creasing brake-pipe pressure become equal, check valve 15 is forced to its seat by the spring between it and the emergency valve, so that no air can flow back from the brake-cylinder to the brake pipe. So far, the operation is the same as in the old standard quick-action triple valve. But with the L Triple other operations occur in emergency as follows : Port c, which leads to the left of the vent-valve piston 31, is connected by port's d and n in the slide valve with port r leading to the brake cylinder. In all other positions of the triple valve^ 76 Air-Brake Catechism port c is open to chamber R; the right side of vent- valve piston 31 is always connected to chamber R; consequently at such times the vent-valve piston has equal pressures on both sides and vent valve 27 is held to its seat by the spring under it. But in emergency, the chamber on the left of the vent-valve piston is connected to the brake cylinder as just described, thereby relieving the pressure on the left, and causing the pressure still remaining in the right to force the piston and vent-valve to the left, as shown in Fig. 26. This opens the vent- valve and connects the supplementary reservoir to cham- ber R through jjort x and the vent valve. The result of this is that the volumes of both supplementary and auxiliary reservoirs are united and become equalized with the brake- cylinder, causing a much greater pressure of equalization than if the auxiliary reservoir alone was used. Q. With 110-pound brake-pipe pressure, what pressure of equalization is obtained in emergency in the brake cylinder with the L Triple Valve? A. Nearly 105 pounds. Q. With the ordinary high-speed brake, the high pres- sure equalization is reduced by a reducing valve; is this also done with the L Triple Valve? A. No. Kef erring to Pig. 26, cavity q in the slide valve does not conect with port r in emergency, so that the safety valve, connecting with port b is shut oil' from the brake cyl- inder. Consequently the high pressure is retained until the brake is released. Q. Why is this? A. Because emergency applications are for use only at times of danger, or to save life, and at such times, the greatest stopping power possible is necessary, regardless of everything else. The weights of cars are greater, and the sj^eeds are higher than those common at the time that the high-speed re- Type "IS' Triple Yalye 71 during valve was introduced, so that now with modern con- ditions, it is considered best to run the risk of sliding a few wheels, if the result makes a considerably shorter stop. Q. Is the safety valve cut off from the brake cylinder at any other time? A. No, only in emergency applications. Q. In what positions of the triple valve does the vent valve operate? A. Only in emergency. Q. Does the vent valve remain open during" the entire emergency application? A. No; as soon as the two reservoirs and brake cylinder become equalized, the spring back of the vent forces it shut. Q. What would happen if the vent valve stuck open? A. Probably an emergency application would occur for every application of the brakes, whether desired or not. At any rate, a much higher pressure of equalization would be obtained than desired. Q. What should be done in such cases? A. Eemove the cap nut from the vent-valve portion and examine the spring back of the vent valve. It is probably broken or weakened so as not to be able to force the vent valve to its seat. Q. If dirt gets on the seat of the safety valve, what will happen? A. The brake will gradually release in service applications,, accompanied by a blow at the safety valve. Q. Is any prevention made against dirt getting to the safety valve? A. Yes, an air strainer is placed in the passage to the safety valve from the slide valve. 78 Air-Brake Catechism Q. With this triple valve, is there any air strainer where the brake-pipe air enters the triple valve, as there is in the old standard quick-action triple? A. Yes, a branch-pipe air strainer is placed in the brake- pipe branch just where it connects with the cylinder pressure head. Q. What diseases and troubles may be found in the L Triple Valve? A. Besides those just mentioned, the same troubles and cures may be applied to the L Triple as already described under the old standard quick-action triple valve. CHAPTER III. WESTINGHOUSE FREIGHT EQUIPMENT. Q. Name the different parts of the equipment. A. 3 (Fig. 27) is the piston sleeve and head, 9 the release spring, 4 the front cylinder head, 2 the cylinder body, A the leakage groove, 7 the packing leather, 8 the expander ring, G the follower plate which holds the packing leather 7 to its place, B the pipe connecting the triple valve and brake cyl- inder, and 15 the gasket which makes a tight joint between the auxiliary, triple, and pijDe B leading to the brake cylinder. Q. Explain the use of the release spring" 9 (Fig. 27). A. When the brake is applied, air is put into the cylinder 2 through pipe B, and the piston 3 is forced to the left, com- pressing the release spring. When the air is released from the brake cylinder, the duty of the release spring is to force the piston to release position as shown in the illustration. Q. What enters the sleeve 3 (Fig. 27)? A. The push rod through which the braking power is transmitted to the brake rigging. Q. Of what use is the expander ring 8? A. To keep the flange of the packing leather 7 against the walls of the cylinder. The expander ring is a round spring. Q. Of what use is the packing leather 7? A. As air enters the brake cylinder, the flange of the pack- ing leather is forced against the walls of the cylinder, thus making a tight joint to prevent the passage of the air by the piston and out to the atmosphere through the open end of the Air-Brake Catechism cylinder ait the left. If the leather leaks, the brake will leak off. Q. Of what use is the leakage groove A (Fig. 27)? A. The piston as shown in the cut is in release position. If on a long train there should be any leak in the brake pipe that would draw a triple piston out far enough to close the exhaust port in the slide valve, and there were a leak into the brake cylin- der, the pressure would gradually accu- mulate and force the piston out, causing the shoes to drag on the wheels were it not for the leakage groove. This will allow any small leakage into the brake cylinder to pass through the groove and out of the other end of the cylinder to the atmosphere. Freight Equipment 81 If the brake connections are taken up so short that the piston will not travel by the leakage groove when the brake is set, the air will blow past the piston through the groove and release the brake on this car. In this case, were it not for the groove, the wheels would be slid. Q. What is the duty of the pipe B? A. When the brake is applied, air passes from the auxil- iary reservoir through the triple and pipe B to the cylinder. When the brake is released, air passes from the cylinder through pipe B, the triple exhaust port and out to the at- mosphere, or, if a retainer is used, it passes from the triple into the retainer pipe, which is screwed into the triple ex- haust, and out of the retainer according to the position of its handle. Q. Of what use is the auxiliary reservoir 10 (Fig. 27)? A. This is where the supply of air is stored with which to apply the brake on this one car. Q. What is the valve on top of the auxiliary? A. It is called the release valve. By lifting on the handle of this valve the pressure in the auxiliary reservoir 10 may be released. If this valve leaks, after the brake is applied, the reduction of auxiliary reservoir pressure thus made will release the brake. Q. What use has the plug 11? A. To drain off any accumulation of water in the auxiliary reservoir. Q. What harm will ensue if gasket 15 leaks? A. The leak may be from the auxiliary reservoir to the atmosphere or from the auxiliary into pipe B leading to ihe brake cylinder. After the brake was applied, the reduction 82 Air-Brake Catechism of auxiliary reservoir pressure caused by this leak would allow the brake-pipe pressure to force this triple to release position and release this brake. The leak would then draw air from the brake-pipe through the triple feed ports, making a brake-pipe reduction that with any other leaks on the train would help to creep on the other brakes. Q. Is the freight-car equipment different from the air- brake equipment on the passenger car? A. It is smaller, but the principle of operation is the same. In a passenger equipment the pipe B does not run through the auxiliary reservoir and the auxiliary and brake cylinder are not fastened together. The appearance is dif- ferent, but aside from size, they are alike. Q. Why has the oil plug- been removed from the brake cylinder? A. So that it will be necessary to take the cylinder apart to clean it. Pouring oil into the oil hole is responsible for the ruination of rubber seats in emergency valves. Q. Fig. 27 shows a standard equipment for freight cars ; are they ever furnished in any other form? A. Yes; the space limitation on some cars forbids the use of the combined equipment illustrated in Fig. 27. In such cases, what is known as the detached equipment is used^ and the brake cylinder and auxiliary reservoir are connected by a suitable pipe. In very exceptional cases two cylinders are used in connec- tion with one reservoir and one triple valve, but the principle of operation remains the same. The usual piston stroke is twelve inches, but this is reduced to eight inches where twin cylinders are used, and in some special combined and detached equipments. Q. How many kinds of freight equipments are there and with what weight of car are they used? Piston Travel 83 A. 8 and 10-inch equipments. The light weights of cars for which each is used are 22,000 to 37,000 for 8-inch, and 37,000 to 58,000 for 10-inch. PISTON TRAVEL. Q. What determines the amount of travel a piston will have? A. The slack in the brake rigging and any lost motion in the car brought out by the application of the brake. Q. How is the piston travel usually adjusted? A. By changing the position of the dead truck levers, unless an automatic slack-adjustment is used. Q. Which is called the dead lever of a truck? A. The one held stationary at the top with a pin. Q. What is the other lever on the truck called? A. The live lever. Q. What is the lever fastened to the piston usually called? A. The piston lever. Q. What is the corresponding lever at the other end of the cylinder in a passenger equipment called? A. The cylinder lever if connected to the cylinder. When connected to a fulcrum as in freight service, it is commonly called a floating lever. Q. Are these levers ever spoken of differently? A. Yes, sometimes both are referred to as cylinder levers. Q. In passenger equipment there is sometimes a lever between the cylinder levers and truck levers, one end of which is connected to the hand brake and the other to the live truck lever. What is this lever usually called? A. The Hodge, or floating lever; the latter name is the one more commonly used. 84 Air-Brake Catechism Q. We have seen in studying the triple valve that a five-pound brake-pipe reduction caused the triple to allow air to expand into the brake cylinder from the auxiliary reservoir until its pressure was reduced five pounds. How much pressure does this give us in the brake cylinder? A. That depends upon the piston travel. It may be more or less than five pounds ; it might be five pounds. Q. Explain this answer. A. We notice that the auxiliary reservoir is much larger than the brake cylinder; the reservoir pressure is high, the brake cylinder has no pressure ; as the reservoir pressure falls, the brake cylinder pressure builds up; the amount that it builds up depends on the volume of the cylinder, that is, on the distance that the piston moves out ; but it must be remem- bered that a small part of the air put into the cylinder goes through the leakage groove before the piston gets by and closes it. There is still another point. If no air were put into the brake cylinder and the piston were pulled out when the exhaust port was closed, a vacuum would be formed. When the air enters the cylinder it must first fill this space to atmospheric pressure before a gage placed on the cylinder would begin to show any pressure. The longer the travel, the more air it would take to fill the space and the less pres- sure there would be for the five pounds reduction in the res- ervoir. Q. Which would give a higher pressure for a given reduction, long or short piston travel? A. Short travel. Q. Why? A. Because with a short travel the same amount of air would be expanded into a smaller space. Q. With the 8-inch freight equipment and old stand- ard triple valve, how much brake-cylinder pressure do we Piston Travel 85 get for a seven-pound brake-pipe reduction with a 6 and a 9-inch travel? A. Eef erring to the table we see that we get seventeen pounds with the 6-inch, and eight pounds with the 9-inch travel. Piston Travel and Resultant Cylinder Pressure for 8-Inch Freight Equipment and Old Style Triple Valve. Brake Pipe Reduction. 4 5 6 7 8 9 10 11 7 30 17 13 10 8 j Piston not en- | tirely out 10 50 39 31 35 30 17 14 11 13 58 56 45 37 31 37 33 19 16 •• 54 50 53 43 50 36 44 33 41 38 19 36 33 49 48 44 35 47 There are two spaces where it says "Piston not entirely out," where no brake-cylinder pressure is given for a seven-pound brake-pipe reduction. This does not mean there was no pressure there, as there must have been or the piston could not have gone out and compressed the cylinder release spring. The or- dinary air gage does not register any pressure less than five pounds, and with a seven-pound brake-pipe reduction the pres- sure gotten in a ten- or eleven-inch piston travel is less than five pounds. Seventy pounds brake-pipe pressure was used in obtaining these figures. Q. With a sixteen-pound reduction? A. Fifty-four pounds with the 6-inch, and thirty-six pounds with the 9-inch. Q. With a twenty-two-pound reduction? A. After the sixteen-pound reduction, the brake did not set any harder on the 6-inch travel because the auxiliary and brake-cylinder pressures equalized at that point, and this brake was fully set. With the 9-inch travel the air from the auxiliary reservoir had 4 inches more space into which to expand, and the brake was fully set when a twenty-one pound 8G Air-Brake Catechism reduction had been made, giving forty-nine pounds brake- cylinder pressure. Q. What does this show? A. That a brake with a short piston travel is more power- ful than one with a long travel; that a brake with the auxil- iary reservoir and brake-cylinder pressures equalized cannot be applied any harder by a further reduction of brake-pipe pressure, and that if piston travel varied in a long train, be- tween 4 and 11 inches, there would be no uniformity in the braking power applied in the different parts of a train. Q. What difference in brake-cylinder pressure is ob- tained with the 8-inch freight equipment using the type "K" triple valve? A. For light brake-pipe reductions, a much higher brake- cylinder pressure is obtained with the type "K" triple valves; while for full-service applications, there is very little differ- ence. Generally speaking, we obtain for a 5-pound brake- pipe reduction about three times as much cylinder pressure with the type "K" triple valve as with the old standard; for a 10-pound reduction, about 50 per cent, more pressure; for a 15-pound reduction, about 20 per cent, more pressure; and for a 20-pound reduction, there is practically no difference. Q. What brake-cylinder pressures are obtained with the 10-inch freight equipment, as compared with the 8-inch? A. Practically the same, for the same brake-pipe reduc- tions. Q. With an 8-inch freight equipment and the old standard Westinghouse triple valve, at about what pres- sures do the brake-cylinder and auxiliary reservoirs be- come equalized when 70-pound brake-pipe pressure is used? A. 4" 5" 6" 7" 8" 9" 10" 11" piston travel 58 56 54 52 51 49 48 47 pounds 12 14 16 18 19 21 22 23 brake-pipe reduction Piston Travel 87 Q. What would be the approximate brake-cylinder pressure, with the travel as given in the table, were the brakes set in emergency, using an 8-inch freight equip- ment. A. 4 in., 5 in., 6 in., 7 in. piston travel. 6£ 61 59^2 58% emergency pressure. 8 in., 9 in.,, 10 in. 11 in. piston travel. 5? '!/o. 56% 55% 55 emergency pressure. Q. Why do the brakes set harder with the quick-action triple in emergency than in service? A. Because in the emergency application the quick-action triples put air from both the auxiliary and brake pipe into the brake cylinder. Q. Can full emergency pressure be obtained after hav- ing made a light brake-pipe reduction in service applica- tion? A. No. Q. Can any gain be made? A. Yes, if the reduction has not been too great. By refer- ring to the table we see that a thirteen-pound reduction sets a 4-inch travel brake in full. If emergency were now used this brake would not set any harder, while we might gain a little on the long travel. With a given brake-pipe reduction, we would gain most on the car with the long travel, but on neither would we get full emergency pressure. Q. Can a train be handled smoothly with uneven travel throughout the train? A. Not as smoothly as when the travel is more uniform. Q. What will be the effect with short travel at the head of the train and long at the rear? A. Having more braking power at the head would cause the slack to run ahead, causing a jar. 88 Air-Brake Catechism Q. What if the short travel were at the rear of the train? A. The tendency would be for the slack to run back and break the train in two, especially if the train were on a knoll. Q. How else would the piston travel affect the smooth- ness of the braking? A. In releasing the brakes. Q. Suppose we had a train half of which had 4-inch travel and the other half 9-inch, which brakes would start releasing first if the engineer had made a ten-pound brake-pipe reduction and then, wishing to release the brakes, increased the brake-pipe pressure? A. They should all start about the same time, but the tendency is always for head brakes to start releasing first if the travel is about alike, as the air enters the brake pipe from the main reservoir at the front of the train, and the pressure is naturally a little higher here when recharging. Q. Is the same true after a thirteen-pound reduction? A. Yes. Q. After a twenty-two-pound reduction? A. No ; the long travel brakes will start releasing first. Q. Why? A. Referring to the table we see that the 4-inch travel was not applied any harder after a twelve-pound reduction had been made; but the 9-inch travel continued applying harder until a twenty-one pound reduction of brake-pipe pressure had been made. With the brakes fully set we have fifty-eight pounds pressure in the auxiliary reservoir and cylinder of the 4-inch travel car and forty-nine on the long. Brake-pipe pressure has to overcome auxiliary reservoir pressure to force the triple pistons to release position, and it is easier to over- come forty-nine than fifty-eight pounds; hence the triple pis- Piston Travel 89 ton on the long travel car will go to release position with less of an increase of brake-pipe pressure than will the triple on the short travel car. Q. State the general rule in regard to this question. A. If reductions have not been continued after cars with the short piston travel have been fully set, all brakes should start releasing about the same time; but if the reductions of brake-pipe pressure are continued after the short travel brakes are fully set, an increase of brake-pipe pressure will start the long travel brakes releasing first. Q. If a long and a short travel brake are started re- leasing from the same pressure at the same time, which will get off first and why? A. The short travel, because the piston has a shorter distance to go and there is a less volume of air to be gotten rid of through the exhaust port of the triple. Q. We have two cars with the same piston travel. What is the trouble if both are started releasing at the same time and one gets off quicker than the other? A. The release spring in one cylinder is weaker or the cylinder corroded. Q. What harm would it do to take a piston travel up to 2 inches. A. The piston could not get by the leakage groove, and the brake would not stay set. Q. What harm would it do to let the travel out to 13 inches? A. The piston would strike the head, and we would have no brake on that car. Q. Does having very long piston travel in a train re- quire any more work of a pump in descending grades? 90 Air-Brake Catechism A. lYes; the air lias to be used more expansively, and the pump will have to supply more air in recharging. Q. If we try the piston travel on a car when standing, will we find it to be the same as when running? A. No. Q. Why not? A. For several reasons; the shoes pull down farther on the wheels when running; the king bolts being loose allow the trucks to be pulled together; spring in brake beams, loose pins in jaws, loose brasses on journals, the give in old cars, and any lost motion that will throw slack into the brake rigging; all these will cause the piston travel while run- ning to be greater than that while standing. Q. If the piston travel is adjusted when a car is loaded, will it remain the same when the car is light? A. It will, if the brakes are hung from the sand plank, but most brakes are hung from the truck bolster or the sill of the car. When the car is loaded, the truck springs are compressed and the shoes set lower on the wheels. When the car is unloaded, the truck springs raise the bolster and car body, thus raising the shoes so that there is less clearance be- tween the brake shoes and wheels. This shortens the, piston travel, as the piston does not have to travel so far to bring the shoes up to the wheels. Q. How could you tell the piston travel on a car if it had no air in it? A. This can be told on freight cars where the hand brake and air brake move the push rod in the cylinder in the same direction when applying the brake. To tell the travel, shove the push rod into the cylinder until it bottoms. Make a mark on the push rod and set the hand brake. The distance the mark on the push rod has moved will be, approximately, the piston travel when using air. Piston Travel 91 Q. How much variation is permissible? A. The smaller the amount of variation the better, but in road service it is the aim to keep piston travel between 5 and 8 inches; on long heavy grades it is customary to have no travel exceed 6 inches. Q. Is there any device which will keep a constant pis- ton travel on a car without any outside aid? A. Yes, a slack adjuster. Q. What slack adjuster is in most general use? A. The American Brake- Slack Adjuster. Q. Is this better than a hand adjustment? A. Yes, because it does its work when the car is in motion, and true travel is had because all lost motion is brought out at this time. Q. What is the most satisfactory travel for general use? A. Between 6 and 7 inches. Q. Where would a moderately long travel be consid- ered better than a short one? A. In a practically level country, where with short travel and a large number of air cars in a train, the train might be slowed up or stopped with a light brake-pipe reduction, thus causing too frequent releases. Q. What harm would a too short travel do? A. The piston might not get by the leakage groove, and the shorter the travel the more danger of sliding the wheels on acount of the greater braking power developed. A too short travel does not give sufficient shoe clearance, and causes a train to pull hard if the brake shoes drag. Q. On most passenger cars piston travel can be taken up by winding up the hand brake a little, as the two 92 Air-Brake Catechism brakes work in opposition to each other. Is this a good practice? A. No ; it is the act of a lazy workman, and is dangerous. Q. How is it dangerous? A. If the air brake is set quickly, it is likely to snap the brake chain, and if a passenger had hold of a hand brake wheel when the brake was applied, if the dog were not caught, the wheel flying round might break his hand or arm. Q. If the hand brake on a car works with the air, and the air brake was applied, what would result if the hand brake were then applied? A. The braking power developed would be too much for the safety of the wheels, rods, etc., since the resultant brak- ing power is equal to the sum of the power of both brakes. Q. If the air brake were then released what difficulty would be experienced? A. Since the hand brake retains all of the power of both brakes, in this case it would be a very difficult matter for the brakeman to release the brake. Q. With this kind of a brake what would result if the hand brake were first applied and then the air? A. If the air brake were more powerful than the hand brake, slack would be thrown into the hand brake chain, and the gain in power would be the excess power of the air over that of the hand brake. If the air power were not as strong as that of the hand no effect would be produced since the pull in the hand brake rod would be diminished an amount equal to the power of the air. Q. If the hand and air worked opposite, that is, they tended to move the push rod in opposite directions to ap- ply the brake (see Fig. 108), what effect would be pro- duced if the air brake was applied and then the hand brake? Piston Travel 93 A. The air brake fully applied is usually stronger than the hand brake, hence the pull on the hand brake rod due to the air pressure would be greater than could be exerted by the brakeman, and the brake wheel could not be turned after the slack in the brake chain had been taken up. Under these conditions no braking power could be gained by using the hand brake. Q. If the hand brake were first applied and then the air what would be the result? A. Applying the hand brake took up all the slack in the brake rigging and forced the push rod and piston in as far as they could go. When the air from the auxiliary reservoir passed through the triple valve to the brake cylinder it would pass through the leakage groove to the atmosphere and simply the power of the hand brake would remain. The clearance in the cylinder being very small would result in a very high pressure when the air first entered, thus tending to strain the rods and brake-chain, but the air would quickly escape as explained. Q. Which is the better brake from the standpoint of danger to the brakemen? A. The one in which both work together. If, where the brakes work opposite, a man is using the hand brake at the same time the engineer uses the air, or an air hose bursts, the power will turn the brake-wheel in the opposite direction tend- ing to throw the brakeman from the train. Q. If the cars of a train are equipped with air and hand brakes working together, and the train was being controlled by air, what could be done if the engineer lost control of the train? A. The engineer could call for brakes and without releas- ing the air, the crew could add the power of the hand brakes to that of the air. 94 Air-Brake Catechism Q. What would have to be done in a case like this if the hand and air brakes worked opposite? A. After calling for brakes it would be necessary for the engineer to make a release before the crew could apply the hand brakes, since if this were not done and the hand brakes were applied, any leakage of brake cylinder pressure would allow the piston to move in, thus throwing slack into the brake rigging and releasing the hand brake. Q. How about leaving cars on a grade if the air brake is applied? A. If the hand and air work together, the hand brake can be applied without first releasing the air and it will re- main set after the air leaks off. If the brakes work opposite, it is necessary to bleed the car before applying the hand brake ; if this is not done, the release of the air brake by leak- age will also release the hand brake and the car will run away. To be on the safe side it is best, as a general rule, to al- ways release the air on one car at a time and apply the hand brake, when leaving a car or train on a grade ; but this would not be necessary, from the stand23oint of safety, if all brakes worked together. Q. Are most brakes designed to work together or op- posite? A. A large majority of freight car brakes are designed to work together, while in passenger service the opposite is true; but the importance of this question x will result eventually in practically all brakes being designed to work together. THE AMERICAN AUTOMATIC BRAKE-SLACK AD- JUSTER AND PISTON-TRAVEL REGULATOR. Q. Name the different parts of the American Brake Slack Adjuster shown in Fig. 29? Slack Adjuster 95 96 Air-Brake Catechism A. The cylinder; the packing leather held in position by the expander ring and follower ; the pawl ; the pawl spring ; the piston spring; the cylinder head and casing; and the ratchet nut. Q. Name the parts shown in Fig. 28? A. 1 is the ratchet nut; 2, the cylinder; 3, the cylinder head and casing; 4, the adjuster screw; a, the port which connects pipe b with the inside of the cylinder; and b, a pipe connection from the slack adjuster cylinder with port a of the main cylinder. Q. What is the object of the lug a (Fig. 29)? A. As illustrated in Fig. 29, its object is to lift the pawl out of the ratchet nut when the adjuster piston is in release position. In the position shown the ratchet nut can be turned by hand to take up or let out slack when necessary, as when applying new brake shoes. Q. Explain the operation of the adjuster. A. In Fig. 29 it is shown both in the normal or release position, and as when applied. If there is sufficient slack in the brake rigging, so that the piston in the large cylinder (Fig. 28) uncovers port a when the brake is applied, cylinder pressure will pass through port a, pipe b, and into the slack- adjuster cylinder (Fig. 29). The piston will be forced out, compressing the piston spring. The movement of the piston disengages the pawl from lug a, and the pawl spring causes the pawl to engage in the teeth of the ratchet nut. When the brake is released and the piston in the brake cylinder is forced to release position by the release spring, port a is connected with the non-pressure end of the cylinder, hence the air in the slack adjuster cylinder passes through pipe b (Fig. 28), port a, and out to the atmosphere through the non-pressure head. When the air is released from the slack adjuster cylinder Slack Adjuster 97 the piston spring forces the piston back and it in turn, through the pawl, turns the ratchet nut which draws the screw away from the c}dinder. Lever 5 (Fig. 28) is fastened to a crosshead attached to the adjuster screw, hence the lever is moved correspondingly, the effect of which is to draw all the brake shoes nearer to the wheels. RELEASED APPLIED Pig. 29. — Sectional End View of Amebic an Automatic Beake Slack Adjustee. 98 Ajr-Brake Catechism Q. How does this shorten the piston travel? A. The shoes being nearer the wheels it will require a less movement of the piston to bring the shoes in contact with the wheels. Q. How many teeth does the pawl skip at each move- ment of the adjuster piston throughout its stroke, and what movement of the crosshead attached to lever 5 (Fig. 28) result? A. The pawl usually skips one tooth, engaging the second of the adjuster nut each tinie. One operation of the adjuster moves the crosshead, connected to the lever, 1-32 of an inch. Q. If the adjuster nut 1 (Fig. 28) is moved one turn, how far will the crosshead attached to the lever 5 be moved? A. One-quarter of an inch. Q. What is the object in having the crosshead move but 1-32 of an inch for each operation of the adjuster? A. When a car is in motion false travel is often produced owing to unevenness of the track and similar causes; if the adjuster should take up all this extra slack the piston travel would frequently be found too short. Q. What is the controlling factor in the amount of piston travel to be permitted? A. The location of port a in the brake cylinder (Fig. 28). It is usually located to obtain an eight-inch "running" travel. Q. If the brake is applied when a car is at rest and the piston travel were but six or six and one-half inches, would you decide that the adjuster was not working prop- erly? A. No. Q. Explain the last answer? A. The slack adjuster adjusts the "running" travel at eight inches, and as the "running" is always greater than the Slack Adjuster 99 "standing" travel, we would expect to find the piston travel shorter when the car was at rest. Q. Would the "standing-" travel be the same on all cars? A. No; this depends upon the total leverage and lost motion. Q. Would the "running" travel be the same on all cars? A. Yes. Q. To apply new shoes it is necessary to»increaset the shoe clearance ; how is this done? A. By turning the ratchet nut 1 (Fig. 28) to the left. Q. After the new shoes are applied how may the piston travel be shortened? A. By turning the adjuster nut to the right. Q. How should we proceed to apply a slack adjuster to a car? A. Drill port a so that brake cylinder pressure can reach pipe b after the cylinder piston has travelled eight inches and erect the parts and piping as shown in Fig. 28, pipe b to be copper. The smaller part of port a (Fig. 30) is drilled with a %-inch drill ; the part of the port into which pipe b connects is drilled and tapped for 14-inch pipe. After erecting, test joints with soap suds. Next put on a new set of brake shoes and adjust the piston travel by means of the dead levers, from six to six and one-half inches. The length of the different rods should be such that the dead and live levers will have an inclination so that when the shoes are worn out they will have a corresponding inclina- tion in the opposite direction. Q. What is the standard length between centers of holes in the rod connecting the cylinder levers when using the slack adjuster? 100 Air-Brake Catechism A. 42 inches for middle connection. Q. What is invariably the cause of the piston travel being too short on a car equipped with an American Brake Slack Adjuster? A. Either some of the slack has been taken up by the hand brake, or the position of the dead levers has been changed. Fig. 30.— Showing Proper Method of Drilling Brake Cylinders WHEN USED WITH THE AMERICAN AUTOMATIC BRAKE SLACK Adjuster. Q. What may occasion the piston travel to become too long? . ' - A. Pipe b may be obstructed, leaks may exist in pipe b, or the slack adjuster cylinder, or the packing leather. The car may have been running some time with the slack partly taken up on the hand brake, a subsequent entire release of I which would introduce an amount of slack that it would I require some time for the adjuster to take up. Slack Adjuster [101 ' Q. Is there ever a time when, with the brake released, the rachet nut can not be turned? A. Yes; when the crosshead is at the end of its stroke. Q. Why can the rachet nut not be turned under these conditions? A. With the ratchet nut at the end of its stroke, and the piston travelling beyond the limit, air will operate the slack adjuster piston, causing the pawl to engage a tooth of the ratchet nut, in which position it will remain, since, the cross- head being at the end of its stroke, the adjuster screw can- not be turned. Q. How can the pawl be disengaged? A. The adjuster is so designed that the adjuster screw when at the end of its stroke is drawn against a set screw at the end of the adjusting nut (Fig. 28), as shown in the cut. Removing this set screw permits of a further movement of the crosshead and the usual operation takes place, allowing the pawl to be disengaged. The adjuster nut may then be turned by hand, thus moving the crosshead nearer the large cylinder for the purpose of giving sufficient slack to permit of the application of new brake shoes. The set screw should always be replaced after the pawl has been liberated and the crosshead moved back. Q. How often should the slack adjuster cylinder be cleaned and lubricated? A. About once in six months, every time the brake cylinder is cleaned and oiled. PRESSURE RETAINING VALVES. Q. With what equipments is the retaining valve used? A. Throughout the country on freight cars, and on engines, tenders, and passenger cars in mountainous country. 102 Air-Brake Catechism Q. Why do they not use it on passenger cars in hilly country? A. It is not necessary, as the higher braking power used in passenger service is sufficient to run moderate hills with safety. Q. Where is it usually located? A. Usually at the end, close to the brake standard on freight cars, and at the end about on the level of the edge of the hood on passenger cars. Q. Where is it located on cars having vestibules? A. On the outside of the vestibule, in which case a special valve is used, the handle of which extends within the vestibule (see Fig. 34). Q. To what is it connected? A. To the exhaust port of the triple by means of a %-inch or %-inch pipe. Q. What is its use? A. To retain pressure in the brake cylinder to steady the train, and keep its speed from increasing too rapidly while the engineer is recharging the auxiliary reservoirs. Q. How do the handles of all valves stand when not in use? A. Straight down. Q. How do they stand when in use? A. In the position shown in the cut (Fig. 31). Q. If the brake is not applied, can it be set by turn- ing up the retainer handle? A. No; the retainer can be used only to hold air in the brake cylinder that has already been put there. Q. Explain the passage of the air through the retainer when not in use. Pressure Retaining Valves 103 A. With the retainer handle pointing down, as when not in use, any air coming from the cylinder would pass through ports h, a, and out to the atmosphere through port e. Q. Explain the passage of air through the retainer when in use, as shown by the cut. A. When the engineer increases his brake-pipe pressure the triple assumes release position, and the air passing from TO EXHAUST PORT OF TRIPLE VALVE Fig. 31. — Pkessuke-Retaining Valve. the brake cylinder has to pass out to the atmosphere through the retaining valve. With the retainer handle turned up, the air passes through ports b, a, and &, until it strikes the weighted valve 20. Any pressure over fifteen pounds forces this valve from its seat and passes through the restricted port opening c to the atmosphere. When the pressure in the cylin- der is reduced to fifteen pounds, it is held back by the valve 20. 104 Air-Beake Catechism * Q. What is the size of the small end of port c? A. One-sixtenth of an inch in diameter. Q. Why is it made so small? A. To keep the brake cylinder pressure from escaping to the atmosphere too rapidly after valve 20 is lifted. Q. How long will it take the cylinder pressure to re- duce from fifty down to fifteen pounds through this re- tainer? A. About twenty or twenty-five seconds, during which time the auxiliary reservoirs with an average length of train have become pretty well charged. Q. Have all retainers this restricted port c? A. No ; in some old retainers there are two ports of 14-inch diameter each. Q. What is the valve shown in Fig. 32? A. This is the double-pressure retaining valve manufac- tured by the Westinghouse Company. It will retain either 15 or 30 pounds pressure in the brake cylinder according to the position of the handle of the valve. It is spoken of as the 15-30 retainer. Q. Explain its operation. A. Its operation is about the same as the 15-pound valve, that is, if the handle points down no pressure will be held in the cylinder when the triple assumes release position. When in a horizontal position it retains 15 pounds and when in a position midway between the horizontal and the vertical a pressure of 30 pounds is retained. It will be seen that the handle controls the lift pin 9, Fig. 32, and the lift pin in turn controls the upper weight. When the handle stands in the horizontal position the upper weight is lifted and the small weight controls the pressure ; if in the mid positon the upper weight is not lifted and the combined weight of the small and large weight act against the cylinder pressure to retain it. The escape of air is as in the 15-pound Pressure Retaining Valves 105 valve, that is, it escapes slowly to tlie atmosphere through the restricted port when the valve is in use. Q. What is the necessity for a valve which will hold either 15 or 30 pounds? A. It has been found that on the heavier grades and at speeds that the railroads wish to maintain, that the 15-pound valve is not sufficient to permit of a recharge being accom- plished without gradually losing pressure. The use of the 30-pound position permits of greater safety, speed and greater tonnage. | PIPE TAP' LOW pressure: 4& y<* Fig. 32. — The Westtnghouse Double-Pressure Retaining Valve, 106 Air-Brake Catechism Q. Will a retainer hold more pressure with a long or a short piston travel on a car? A. It holds the same pressure regardless of the travel. The volume held is greater on the long travel car. Q. How do we test retainers? A. Have the engineer apply the brakes, and turn up the retainer handles. Then signal him to release, and wait about half a minute, after which walk along and turn down the handles. If a blow accompanies the turning down of the handles, the retainer is working properly, otherwise the pressure has leaked away. Q. What troubles would make a retainer inoperative? A. A leak in the plug valve operated by the retainer handle; weight 20 (Fig. 31) being gone or dirt on its seat; a split pipe leading from the trij)le exhaust to the retainer; or a leak in the packing leather in the brake cylinder which would allow the air to escape to the atmosphere. Q. What could be the trouble with the retainer if, after the brake was applied and the retainer put in use, no air escaped from it when the engineer increased the brake-pipe pressure? A. Port c might be blocked. Q. If we wish to use a retainer in descending a grade, should the handle be turned up before or after the brakes are applied? A. It makes no difference, if everything is in proper con- dition. Q. Explain a case where it would not be proper to turn up the retainer handle until just before we wish to use it. A. If the rubber-seated or the slide valve in the triple leaked, and we turned up the retainer handle, air would ac- cumulate to a pressure of fifteen pounds in the cylinder if Pressure Retaining Valves 107 the leakage groove were closed and set the brake on this car. If the train were just pulling over a summit, the brake being on might stall the train. Q. How could we tell if it was safe to turn up a re- tainer handle before reaching" the top of a hill and not have the brakes drag? A. Put the hand over the exhaust port and hold it there a few seconds, to see if any air is issuing; if not, it is safe to turn up the handle. Q. Give a rule to produce best results in using the retainer. A. In testing retainers while standing, turn up the handles at your convenience before or after the brakes are applied ; but using them on the road, turn them up after the brakes are applied or a short time before wishing to us them. Q. Is a retainer ever used except to steady a train when recharging? A. Yes; when brakes have been applied too hard, a few are sometimes used to keep the slack bunched after releasing, when drifting along preparatory to making a stop. Q. Set a brake with the full service application, then turn up the retainer handle, release and recharge. After charging the auxiliary in full again, make a full service reduction. Will the brake set any harder one time than another? A. Yes, it will set harder the second time. Q. Why? A. When we started to apply the brakes the first time, we had seventy pounds auxiliary reservoir pressure and nothing in the brake cylinder. The second time Ave had seventy in the auxiliary and fifteen pounds in the brake cyl- inder, By comparison we see that we had more air the 1 os Air-Brake Cateoh ism » second time with which to do our braking, and the pressures will therefore equalize higher. Q. Would we gain more the second time over that of the first with a long or a short piston travel? A With the Long, because the retaining valve on the long travel ear retains the same aumber of pounds in the cylinder as on the short one, but a Larger volume; having ;i greater volume the pressures equalize correspondingly higher. Q. Do we gain the whole fifteen pounds more the sec- ond time over what is obtained the first? A. No; we gain from about three to six pounds pressure. according to the piston travel. Q. About how much pressure do we get in the brake cylinder for a five-pound brake-pipe reduction? A. .It varies from seven to eleven pounds with average piston travel. It may be more or less, but this would be a fair average. Q. After getting the use of the fifteen pounds that the retainer holds, how much pressure would we then get in the cylinder for a five-pound brake-pipe reduction with an average piston travel? A. Between thirty and forty pounds. Q. Where a twenty-pound reduction will set a brake in full without the aid of the retainer, how much reduc- tion is necessary with the fifteen pounds it holds to aid? A. Prom twelve to fifteen pounds with fair travel, and old style New York or Westinghouse triples about 15 pounds with the quick-service triple. Q. Name another gain after obtaining the use of the retainer. A. If we have to apply the brakes in full, it does not take so long to recharge, as the auxiliary and brake cylinder pressures equalize liigher with the retainer to aid,. Table 10! (1) (2) (3) (4) CO (6) (7) ■5 I « k- § > P) o go £ Inches. o 1 bj) a Pounds. 5 Emergency \v: S" Retainer. oPh Oh 10 Pounds. 53 S| go -£,2 ,, O CD lis Ph £ in Pounds. CO Pounds. Pounds 4 62 65 23 59 571/o, 61 5 Gl 63 I91/2 55 551/2 59 6 59% 63 I31/2 51 53 58 7 58i/ 2 62 11% 43 52 57 8 571/2 62 10 38 501/2 56 9 56i/ 2 6 11/2 8 35 48 55 10 551/2 61 + 32 46 54 11 55 60 + 30 45 53 The above figures were obtained by taking an average of four tests for each condition, using old style Westinghouse triple valves. Each test was made with a brake pipe and auxiliary reservoir pressure of seventy pounds. The first column represents the piston travel. The second column represents the brake-cylinder pressure ob- tained in emergency. The third column represents the brake-cylinder pressure ob- tained in emergency after the retainer has been used; that is, there was already a pressure of fifteen pounds in the brake-cylin- der held by the retainer when the emergency was used. These figures would be the same for either the old style or quick-service Westinghouse triple valves. The fourth column represents the brake-cylinder pressure ob- tained with a five-pound service reduction. The fifth column represents the brake-cylinder pressure ob- tained with a five-pound service reduction after once obtaining the use of the air held in the cylinder by the use of the retainer. The sixth column represents the brake-cylinder pressure ob- tained with a full service reduction. The seventh column represents the brake-cylinder pressure ob- tained with a full service reduction after getting the use of the retainer. + simply means that the gauge used registered no pressure less than five pounds. With an 11-inch travel the air is expanded into so large a space that a very small pressure is obtained. The table should be read from the left to the right. 110 Air-Brake' Catechism Fig. 33. — Retaining Valve used Fig. 34. — Pullman Retaining with 12, 14 and 16-inch brake valve, used on vestibule Cylinders. Cars. O mm l mi l Fig. 35. — Standard Retaining Valve used with 6, 8 and 10- inch Brake Cylinders. Fig. 36. — Driver-brake Retaining Valve. Pressure Retaining Valves 111 Q. What are the retaining* valves shown in Figs. 33, 34, 35, and 36? A. Figs. 33 and 34 represent valves designed to operate with 12, 14 and 16-inch cylinders. Though slightly dif- ferent in structure, the operation is practically the same as the one already described. Q. Why is it necessary to have two sets of retaining* valves for use with 6, 8, and 10 ; and 12, 14, and 16-inch cylinders? A. It is essential in releasing brakes that the pressure in all cylinders be reduced about alike. The ports in the valves for use with 12, 14 and 16-inch cylinders are correspondingly larger than those in the valves for use with the smaller cyl- inders. Q. What is the purpose of the extension handle (Fig. 34)? A. This valve is for use on vestibule cars. The body of the valve is located outside the vestibule, but the handle ex- tends within. Q. What is the common name for this valve? A. The "Pullman Retaining Valve." Q. What is the difference between this valve and the corresponding one for use on cars not equipped with vesti- bules? A. The keys are set at right angles to each other in the bodies of the two valves and, as already explained, the "Pull- man" valve has an extension handle. Q. Is the operation of the two and the results accom- plished the same? A. Yes. Q. How many kinds of retaining valves are furnished by the Westinghouse Company, and what is their use? 112 Air-Brake Catechism A. Five. The one shown in Fig. 35 is for use with 6, 8, and 10-inch cylinders on non- vestibule cars; practically the same valve, but with an extension handle and key at right angles, is used on vestibule cars. Figs. 33 and 34 represent the corresponding valves for use with 12, 14, and 16-inch cylinders. Fig. 36 is a cut of the Driver-Brake Betaining Valve. Q. How does the Driver-Brake Retaining Valve oper- ate? A. In the same general way as the other, except that, if so desired, it may be placed on lap, as indicated, in which position no air can escape from the brake-cylinder. When the handle points straight up the usual 15 pounds is retained, when the triple piston is forced to release position. Q. For what special use was the Driver-Brake Retain- ing Valve designed? A. For use on freight engines and those hauling long passenger or excursion, trains. It furnishes a means, within the control of the engineer, by which the slack of a train may be kept bunched, if desired, when drifting up to a water crane, releasing brakes at slow speeds, and under similar conditions, This, of course, is not necesary when the engine is equipped with straight air. Fig. 36 a. Nine and One-half Inch Pump. CHAPTEE IV. WESTINGHOUSE AIR PUMPS Q. What sizes of pumps are there? A. The 8, 9y 2 , 11, and 8%-inch cross compound. Q. What is the use of the pump in the air-brake sys- tem? A. To compress the air nsed in applying and releasing the brakes. Q. Which pump has been mostly used and why? A. Two 914-inch pumps, because the number of air cars now used in trains requires a greater capacity to insure re- charging the train more quickly in descending grades. The use of two pumps also does away with an engine failure if one pump should fail. Q. How is dry steam obtained for the pump? A. A pipe is screwed into the dome near its top and a pump throttle conveniently located in the pipe, or a dry pipe is run from the top of the dome back through the boiler and coupled to a pump throttle screwed into the top of the boiler inside of the cab. Steam is also taken from a "fountain" conveniently located. Q. What would happen if this dry pipe leaked inside the boiler? A. Water would work into the pump and wash out the oil, causing the pump to groan and cut. 114 Air-Brake Catechism nx^ m ^a^ 1 Fig. 37. — Westinghouse 9%-inch Air Pump. 9 1 /2-Inch Pump 115 ^&* l u ; k ^r — or Fig. 37. — Westinghouse 9%-inch Aie Pump. 116 Air-Brake Catechism Q. What is placed between the pump throttle and the pump? A. The lubricator and pump governor. Q. How are they located? A. The pump governor next to the pump, and the lubri- cator between the governor and pump throttle. Q. What would happen if the lubricator were placed next the pump? A. When the pump governor shut off the steam, with the lubricator ordinarily used, the steam between the lubri- cator and pump governor condensing would form a vacuum that would draw all the oil from the lubricator, and there would be a great waste of oil. 9%-INCH PUMP. Q. What is the office of the parts in the top head of the 9 1 / 2 -inch pump (Fig. 37)? A. They with the reversing rod 71 form the steam valve motion of the pump. Q. What is Fig. 37? A. Two views of the 9i/2-inch pump showing the steam and air pistons and rod, and the valve motion in the top head. Q. What are ports b, d, and c (Fig. 37) ? A. They correspond exactly to the ports in the valve seat of a locomotive. In Fig. 37, we see that b leads to the bottom of the steam cylinder, c to the top, and d leads to the exhaust pipe at Y. Q. Of what use is port t (Fig. 37)? A. It is a port by means of which chamber E at the left of the small piston 79 is connected with the atmosphere through port d. 9%-Inch Pump 117 Q. If this port were not there, would the pump re- verse? A. No; when the main valve pistons 77 and 79 moved to the left, a back pressure would be formed in chamber E that would stop the reversing movement of the pistons 77 and 79 and stop the pump. Q. Explain the passage of steam after it enters the pump at X and its effect. A. Steam coming from the boiler through the pump gov- ernor enters the pump at X, thence passes through ports a, a and a (Fig. 37), into chamber A between the main valve pistons. The area of piston 77 being so much greater than that of 79, the steam moves these pistons to the right, carry- ing the slide valve 83 with them to the position shown in Fig. 37. Steam in chamber A is now free to pass through ports b, b' and b 2 underneath the main piston 65. Q. What would become of any steam above piston 65? A. Any steam above this piston is free to pass to the at- mosphere through ports c, c ' , the exhaust cavity B of the slide valve, d, d' , d 2 , and through the exhaust pipe from Y. Q. How is the pump reversed? A. The main piston 65 is now being forced up by the steam pressure, and just before it reaches the top of its stroke the reversing plate 69 strikes the lug j on the reversing rod 71, lifting the rod. As this rod is lifted the reversing slide valve 72 is carried up with it, and the pump is reversed. Q. What is the duty of the reversing slide valve 72? A. The duty of this valve is to admit and exhaust steam from chamber I) between the piston 77 and head 84, and, as now shown, it exhausts steam from cavity D through ports h and h' , port II of the reversing slide valve, and through ports f, f , d f d' } d 2 , and out at Y. 118 Air-Brake Catechism Q. How does raising the reversing slide valve reverse the motion of the pump? A. As the reversing valve is lifted by the rod 71, port g in the bushing is exposed to the steam pressure which is al- ways in chamber C, which is in constant communication with chamber A by means of ports e and e . When valve 72 is raised, steam passes through port g into cavity D. We now have equal steam pressure on both sides of piston 77,. and it is balanced; but the pressure acting on the right of piston 79' moves the pistons and the slide valve to the left connecting the steam pressure in chamber A with the top of piston 65 through ports c and c and the under side of piston 65 is connected with the atmosphere through ports b 2 , b' , b, cavity B of the slide valve 83, d y d' 9 d 2 y and out at Y. Q. The piston 65 is now on its down stroke; what brings the stroke to the point from which we started? A. The reversing plate 69 strikes the button at the bot- tom of the reversing rod 71 and pulls the reversing slide valve 72 down to its position as shown in Fig. 37. We have now completed one entire stroke of the pump. Q. Which are the receiving valves? A. Those marked 86 at the left of the air cylinder. Q. Which are the discharge valves? A. Those marked 86 at the right of the pump. Q. Describe the action of the air end of the pump. A. As piston 66 is raised, the air above the piston is compressed and a vacuum would be formed underneath if air from the atmosphere did not enter through the lower receiving valve 86. The ports are so arranged that the pressure above the pis- ton will strike the receiving valve from above, forcing it to its seat, and the discharge valve underneath, forcing it 91/ 2 -Inch Pump 119 from its seat, allowing the compressed air to pass down and out into the main reservoir at Z. The suction underneath the piston allows atmospheric pressure entering at W to force the lower receiving valve from its seat and fill the cylinder underneath the piston with air. The lower discharge valve 86 is held to its seat by main reservoir pressure. When the pump is reversed, the opposite valves from those just described are affected in the same way. Q. Of what use is the port in the cap 74 which leads to the top of the stem 71? A. This port is connected with the top end of the steam cylinder. Were it not for this port there would be a back pressure on top of stem 71 which would not allow the revers- ing slide valve to be raised to reverse the pump. This port is connected with the atmosphere through the top end of the steam cylinder, each time this end of the cylinder is connected with the atmosphere. Q. What is the capacity of a 9y 2 -inch pump in good condition? A. With one hundred and forty pounds of steam pressure, a 9i/2-inch pump will compress air from zero to seventy pounds in about thirty-eight seconds in a reservoir 26% x 34 inches, and from twenty to seventy pounds in about twen- ty-seven seconds. When operating at one hundred and twen- ty single strokes per minute, it should deliver about twenty- eight cubic feet of free air per minute against ninety pounds air pressure. 9%-Inch Pump — Peculiarities, Troubles, Care. Q. What should be done in packing the pump? A. It should be packed loosely and the gland nuts 96 screwed up only sufficient to prevent a blow. Do not use a 120 Air-Brake Catechism wrench if no blow exists when the gland is screwed up by hand. Q. Should asbestos or anything containing much rub- ber be used in packing a pump? A. No; asbestos hardens and is hard to remove, and rub- ber is likely to wear the stem too much. Q. How often should the air end of the pump be oiled? A. Modern practice demands that a pump in freight and passenger service should be oiled according to the work which they perform. The old 'method of oiling a pump only when it groans has been abandoned. Q. Some pumps have been run without ever oiling the air end ; how did the lower cylinder receive its lubrication? A. From the swab which should always be placed on the piston rod, and from the oily condensation that follows down the rod. Q. What kind of oil should be used in the air end of the pump? A. A good quality of valve oil gives the best results. The same oil that is used in the steam c}dinder also gives best results in the air cylinder. Q. What care should be taken in starting a pump? A. It should be started slowly so as to get a pressure of twenty or thirty pounds for the air piston to cushion upon, and the condensed steam should be gotten rid of before the pump attains any speed. Get the lubricator at work as soon as the pump is started. Q. Does any harm result from oiling the air end of the pump through the suction? A. Yes; the suction holes are stopped up, the air valves gummed, and a generally dirty and ineffective pump results. 9%-Lntch Pump 121 Q. What trouble will cause the pump to blow? A. Packing rings in the main steam and reversing pis- tons leaking, slide valve 83, or a leaky reversing slide valve 72 are the main troubles. Q. What w'll cause a pump to pound? A. It will pound if it is not fastened firmly, if the air valves are stuck, or if there is too great a lift of air valves. Sometimes it will pound if the reversing plate is worn too much to reverse the pump quickly enough, or if the nuts be- low the air piston are loose. Q. What would be the effect if the top discharge valve were stuck open? A. Main-reservoir pressure would always be on top of the air piston; this would cause a slow up-stroke and a quick down-stroke of the pump. No air would be drawn into the pump on the down-stroke. If the oil cock were opened on the pump, there would be a constant blow at that point as long as there was any pressure in the main reservoir, and no oil could be put into the air cylinder, as it would be blown out by the escaping air. Q. What would be the effect if the bottom discharge valve were stuck open? A. The same effect as above described, only on the opposite stroke of the pump. In this case the oil cock would not tell us anything. Q. What would be the effect if the top discharge valve were stuck shut? A. The pump would have a slow up-stroke, and unless the valve were forced from its seat, would stop or go slow enough to allow the pressure above the air piston to leak by the packing rings when the air pressure above the piston became as high as the steam pressure, 122 Air-Brake Catechism Q. What would be the effect if the bottom discharge valve were stuck shut? A. The same effect as just described, but on the opposite stroke. Q. What effect would follow if the top receiving valve were stuck open? A. Air would be drawn into the pump on the down-stroke and forced back through the inlet port to the bottom of the air cylinder on the up-stroke. By placing the hand on the air inlet and watching the piston this trouble may be easily located. The pump would have a tendency to work faster on the up-stroke. Q. What effect would follow if the bottom receiving valve were stuck open? A. The same as just described, but on the opposite stroke, Q. What would be the effect were the top receiving valve stuck shut? A. No air would be drawn into the pump on its down- stroke, and a partial vacuum being formed above the piston would cause the pump to have a slower down-stroke, as the vacuum would be working against the steam, and a faster up-stroke, as the vacuum would be working with the steam. Q. What would be the effect if the bottom receiving valve were stuck to its seat? A. The same as with the top receiving valve stuck shut, but on the opposite stroke. Q. How may a stuck valve usually be loosened? A. By tapping the valve cage lightly. Q. How will a pump work with dirt on the seat of a discharge valve? A. The same as with a stuck receiving valve. The dirt on the valve allows main-reservoir pressure to feed back into 91/ 2 -Inch Pump 123 the pump and aid the steam on half the stroke, causing one stroke to be quick, and work against the steam on the other stroke, causing the pump to work slow. Q. How could we tell that a receiving valve was stuck shut, or a discharge valve open, aside from the erratic action of the pump? A. The hand placed on the strainer would feel no air drawn in on one-half of the stroke. Q. How can we tell if the top discharge valve has a poor seat? A. Open the cock 98 (Fig. 37) and air will issue thence constantly if the dirt on the seat of the valve allows main- reservoir pressure to feed back into the cylinder. Q. What caused some of the first 9 1 / 2 -inch pumps to stop? A. The port g did not extend quite far enough, and the wear of piston 77 would sometimes allow it to travel far enough to close port g entirely, and the pump could not be re- versed. Q. How may a pump often be started if it stops? A. By jarring lightly on the top head. Q. At what speed are good results obtained from a pump? A. From forty-five to sixty double strokes a minute on a level, but in handling air trains on a grade this speed should be increased according to work to be done. Q. Why is it best not to run a pump too slow? A.. A pump running too slow will allow the air that is being compressed to leak by the packing rings 67 and air will not be drawn in at the other end of the cylinder as it should. With sixty strokes to the minute, a pump will make more air than with the same number of strokes spread over three 124 Air-Beake Catechism minutes. In the latter case the compressed air has too much time to leak by the air piston-packing rings. Q. How can we tell if the pecking rings in a pump are loose? A. Have the pump working at fair speed and put the hand on the air inlet to see if the air is drawn in full stroke. Try this on both strokes, and if air is drawn in only during a part of each stroke, the rings are loose. Q. What lift should the receiving and discharge valves have? A. 3/32 of an inch. Q. What will cause a pump to heat? A. Too small lift of air valves, racing a pump, loose air piston-packing rings, using a small main reservoir on long trains, packing the piston rod too tight, or using so much oil on the air end of the pump that the pipe leading from the pump to the main reservoir is partly closed by the oil being baked to it. The pipe gradually becomes so small, that the friction caused by the air being forced through it causes the air to heat. This heat spreads to the pump. Q. What should be done to cool a hot pump? A. Ease up on the speed, when possible, if running fast, remove cap 74, and pour a small amount of good oil into the pump. Q. If the packing burns out of a pump, can it still com- press air? A. Yes; the lower half of the air cylinder will not be af- fected. Q. Does compressing air cause it to heat? A. Yes; the higher the pressure the greater the degree of heat, because of the friction due to forcing the air particles closer together. 9%-Inch Pump 125 Q. What is likely to be the trouble if a pump dances? A. A leak on the seat of the, reversing slide valve or a bent reversing stem ; also a burr being worn on the reversing plate, thus allowing the button on the stem to catch. Too much lubrication has also been known to cause the reversing valve to fall and the pump to reverse. Q. How should a pump be located? A. It should be where the engineer will notice it if it stops. Under no consideration should it be located lower than the main reservoir, as dirt and water would stay in the pump. Q. How may a pump be cleaned? A. By allowing a solution of lye in hot water to work through the pump. The pump should be worked slowly and the water caught in a pail before it enters the main reser- voir. Eun the solution through several times ; then run clean hot water through to wash out the lye, or it will eat the leather gaskets throughout the brake system. Q. Where does the exhaust pipe connected to the pump at Y lead? A. Usually to the smoke box in the engine, but this prac- tice is gradually giving way to the better one of running the exhaust pipe into the exhaust passage from the main cylinder to the stack. This latter method almost does away wifh the draught on the fire caused by the pump exhaust thus saving fuel, and the pump makes very little noise in working. Some engines are piped to carry the pump exhaust up over the cab, but this is awkward, noisy, and keeps the cab dirty. Q. What effect would be produced if the gasket under the top head leaked? A. If the leak were between the two ports, one leading to the top and the other to the bottom of the main piston, the pump would stop. 126 Air-Brake Catechism The accompanying table shows heat due to compression. This heat depends upon the initial temperature. The rise in temperature is due to the heat of compression. per ature of air before compression 60° 90° cc a a compressed to 15 lbs. 177° 212° a CC cc cc 'c 30 cc 255° 294° a a cc cc cc 45 cc 317° 362° cc CC cc a cc 60 cc 369° 417° a a a cc cc 75 (C 416° 465° cc cc a a cc 90 cc 455° 507° a a cc cc cc 105 (C 490° 545° a a cc cc cc 120 cc 524° 580° Westinghouse "Eight and Left-Hand" Nine and One- Half Inch Pump. Q. What is the difference between the nine and one- half inch pump shown in Fig". 38 and the one shown in Fig. 37. A. The operation of the two pumps is exactly the same; the parts are identical with the exception of the steam and exhaust connections, and the drain cock put in to drain any accumulation in port A. Q. How do the steam and exhaust connections differ. A. Both are extended through to the other side of the pump for convenience in piping in case it is desirable to locate the pump on the left side of the engine. Q. Explain the proper use of the connections as shown in Fig. 38. A. A is the steam inlet and B the steam exhaust. Q. What must be done if this pump should be changed to the right side of the engine? 9%-Inch Pump 127 A. Remove plug at C and fittings at A and exchange them; the same should be done with the plug at D and fit- tings at B. C will then be the steam inlet and D the steam exhaust. Fig. 38. — Right and Left-Hand Pump. 128 Air-Brake Catechism Q. Is there any difference in the air cylinder on a right and left hand pump? A. Usually none, but sometimes an air cylinder is fur- nished with admission and discharge connections on each side, similar to the steam cylinder, so that the connections may be charged in the same way. Q. Explain the operation of this pump. A. A description of the operation of this pump would be but a repetition of what is said in the chapter concerning the standard nine and one-half inch pump. Eleven-Inch Pump. Q. What are the dimensions of cylinders and the stroke of the eleven-inch as compared with the nine and one-half inch pump? A. The nine and one-half inch pump is 9%" x 9%" x 10" stroke, as compared with 11" x 11" x 12" stroke with the eleven-inch pump. Q. What are the comparative capacities of the two pumps? A. With a piston speed of 100 feet per minute (which means 100 single strokes per minute for this pump), and operating continuously, the capacity of the eleven-inch pump is about 60 per cent, greater than the nine and one-half inch pump; under the above conditions the larger pump will com- press 45 cubic feet of free air while the nine and one-half inch pump compresses 28 cubic feet, against ninety pounds air pressure in both cases. These figures, however, are for a moderate pump speed, and these capacities can, if desired, be exceeded, but in the same proportion. Q. Explain the operation of the eleven-inch pump. A. Although some of the parts are slightly different in Cross-Compound Pump 129 construction, the operation is the same as that of the nine and one-half inch pump described in the chapter beginning on page 113. Q. Two sets of plugs are shown on either side of the steam cylinder; of what use are they? A. These plugs are for convenience in piping the pump. The l^-n^h- plugs are at ojDposite ends of the same steam port. The 2-inch plugs are at opposite ends of the exhaust port. The openings are used according to which side of the engine the pumps are located, and provide a means of mak- ing the piping simple, since a steam port opening is toward the cab and an exhaust opening toward the front end, if placed on either the engineer's or fireman's side. Q. Do the nine and one-half inch pumps have this pro- vision? A. The one usually placed on the engineer's side, and known as the Eight-Hand Pump, does not, while the Eight and Left-Hand Pump, which may be used on either side, does. The S^-Inch Cross-Compound Pump. Q. "Why are larger air compressors necessary in mod- ern railway service? A. Because of the increased size and weight of locomo- tives and cars, requiring larger brake equipment, and of the increased number of cars hauled in single trains. Q. What is the type of air pump shown in Fig. 39? A. It is called the 8%-inch cross-compound pump, and the drawing illustrates its exterior. Q. How many cylinders has the cross-compound pump, and what are they called? A. It has four cylinders, two steam and two air. 130 Air-Brake Catechism Q. Why is this pump named compound? A. Because in the steam end it uses the steam expansively in two cylinders, and in the air end it compounds the air in compression. Fig. 39. — 8%-Inch Cross-Compound Pump. k Q. Is this type of pump more economical in the use of steam than the familiar types which have already been described? A. Yes, it is more economical in steam consumption, us- Cross-Compound Pump 131 ing less than one-third the steam required by the 9%-inch pump to compress the same quantity of air. Q. In general design and construction, how does it compare with the 9y 2 -inch and 11-inch pumps? A. With the excejjtion of the number of cylinders and the type of main slide valve, it is of the same general plan. Q, Which are the steam cylinders and which are the air? A. The two upper cylinders are the steam and the two lower the air, this arrangement being the same as that of the other Westinghouse pumps. Q. What are the diameters of the respective cylinders? A. The smaller steam cylinder is 8% inches, the larger is 14% inches, in diameter; the smaller air cylinder is 9 inches, and the larger 14% inches in diameter. Q. What names are used to distinguish these cylin- ders? A. The smaller cylinders are called the high-pressure steam and the high-pressure air, while the larger ones are called the low-pressure steam and the low-pressure air. Q. How are the high and the low-pressure cylinders arranged with respect to each other? A. The high-pressure steam cylinder is above the low- pressure air cylinder, and the low-pressure steam is above the high-pressure air cylinder. Q. What type of reversing-valve gear is employed in this pump? A. The same as in the D^-inch and the 11-inch pumps. Q. Does it operate the same? A. Practically the same. Q. How are the pistons and the rods connected? A. The high-pressure steam and the low-pressure air pis- 132 Air-Brake Catechism STEAM INLET. Pig. 40. — Diagram of Cross-Compound Pump. Up Stroke High- Pressure Side, Cross-Compound Pump 133 STEAM INLET. 40 3S Pig. 41. — Diagram of Cross-Compound Pump. Down Stroke, High-Pressure Side. i 134 Air-Bbake Catechism tons are connected by one piston rod, and the low-pressure steam and the high-pressure air pistons are connected by the other. Q. How many air valves has the pump, and what are they called? A. It has ten valves; there are four receiving, four inter- mediate, and two discharge valves. Q. How many air strainers has the pump? A. Two, one for the upper receiving valves and one for the lower. Q. In which air cylinder are the air-receiving valves located? A. In the low-pressure air cylinder. Q. Where are the intermediate air valves located? A. They are located between the low-pressure and the high-pressure air cylinder. Q. Where are the discharge valves located? A. They are located in the ends of the high-pressure air cylinder. Q. What is the difference between the main valve in the cross-compound and the ordinary D slide valve of the 9^2-inch pump? A. The main valve in the cross-compound is made up of five pistons connected rigidly together; a large one on one end; a small one on the other; and three intermediate pis- tons all the same size. Q. What are Figs. 40 and 41, and what do they show? A. They are diagrammatic drawings of the cross-com- pound pump, and show the various ports and passages and the relative positions of the various parts on the up-stroke and the down-stroke of the pistons. Q. Explain the operation in the steam end on the up- stroke of the high-pressure steam piston. Cross-Compound Pump 135 A. Keferring to Fig. 40, steam from the boiler enters the pump' at the point marked "steam inlet/ 7 flows through pas- sage a to the top head and fills the main valve chamber be- tween the small and first intermediate pistons, and also be- tween the third intermediate and large pistons. It also flows into the reversing valve chamber. The chamber D to the right of the large main-valve piston is connected to the exhaust through ports m and I. The small main valve piston is always connected to the exhaust through port c. The three intermediate pistons being equal in diameter are always bal- anced. The large and small pistons have steam pressure in- side and exhaust outside, which results in forcing the main valve to the right to the position shown. This brings chamber b in register with port and passage g leading to the lower end of the high-pressure steam cylinders, thus providing for the admission of live steam under the high-pressure steam pis- ton 7, starting it on its upward stroke. Q. Where does the steam go that was used in the high- pressure steam cylinder on the previous down stroke? A. Port c in the slide valve seat, which leads into the up- per end of the high-pressure steam cylinder, connects through chamber h with port d in its seat, which leads into the upper end of the low-pressure cylinder, thus the steam from above the high-pressure piston exhausts through port c, chamber h, and port d into the upper end of the low-pressure steam cyl- inder, and drives the low-pressure piston on its down stroke. Q. How is the steam in the low-pressure cylinder below piston 8 released as the piston comes down? A. Port and passage / in the cylinder and top head is con- nected by chamber i with port e leading to the steam-exhaust pipe. Q. Does the low-pressure piston make its down stroke as the high-pressure piston makes its up stroke? 136 Air-Brake Catechism A. Yes, and vice versa, as the low-pressure piston makes its up stroke the high-pressure piston makes its down stroke. Q. How is the stroke of the steam pistons reversed? A. When the high-pressure steam piston approaches the upper end of its cylinder, the reversing plate 18 engages the shoulder on the reversing valve rod 21, forces this rod and the reversing valve 22, which is attached to it, upward to the position shown in Fig. 41. The reversing valve 22 in this position admits steam to chamber D outside the large piston through port n. This balances the large piston, and leaves the small piston alone unbalanced, having steam pressure on the right and exhaust on the left. This results in moving the main valve to the left as shown in Fig. 41. In the position shown, live steam enters the upper end of the high-pressure steam cylinder through chamber b and port c in its seat, thus causing the high-pressure steam piston to start on its down stroke. At the same time the high-pressure steam piston starts on its down stroke, the steam in the lower end of the high-pressure steam cylinder exhausts through port and pas- sage g in the slide-valve seat, chamber i, and port and passage / leading to the lower end of the low-pressure steam cylinder and starts the low-pressure piston on its up stroke. The steam above piston 8 escapes to the atmosphere through port d, cavity h and port e. Q. Explain the operation in the air end. A. Commencing with the low-pressure air cylinder, it will be seen that as the low-pressure air piston is making its up stroke, it tends to form a vacuum behind it and the atmos- pheric pressure raises the lower air-inlet valves 38 and air flows into the cylinder past these valves, to fill the partial ►vacuum formed by the moving air piston. The air contained in the cylinder above the piston is compressed, as the piston advances, and is forced past the intermediate air valves 39 into the upper end of the high-pressure air cylinder above the Cross-Compound Pump 137 high-pressure piston 10. Upper air-inlet valves 37 are forced to their seat during the up stroke of the low-pressure piston, thus preventing the escape of any air back to the atmosphere. The air compressed by piston 9 on its up stroke is forced into the chamber above piston 10 and aids the steam acting down- ward on piston 8 to force pistons 8 and 10 downward. On the down stroke of the high-pressure air piston 10, the air under it which was previously forced into this cylinder, by the low-pressure air piston on its down stroke, is com- pressed to main reservoir pressure and forced out past the lower discharge valve 42 to the air-discharge pipe and the main reservoir. On the down stroke of the low-pressure and the up stroke of the high-pressure air pistons, the operations just explained are repeated, only the air is drawn in from the atmosphere past the upper discharge valves 37, and is discharged past lower intermediate valves 40 into the lower end of the high- pressure air cylinder, and is discharged to the main reservoir past.the upper discharge valve 41 into the air- discharge pipe and main reservoir. Q. What maximum pressure does the low-pressure air piston work against? A. About 40 pounds. Q. What maximum pressure does the high-pressure air piston work against? A. Main-reservoir pressure, whatever it may be. Q. How does the capacity of the cross-compound pump compare with that of the other air pumps? A. When working with 200 pounds steam pressure, against a main reservoir pressure of 130 pounds it has nearly three and one-third times the capacity of the 9%-inch pump, two and one-quarter the capacity of the 11-inch pump, one and 138 Air-Brake Catechism eight-tenths the capacity of the tandem compound pump, and one and one-half times the capacity of the New York No. 5 duplex pump. Q. Why is it that the air capacity of this pump is so much greater than that of any of the others? A. Making due allowance for its size, its greater capacity and efficiency is due to its design which has cut down the clearance ratio to almost nothing, and because the air pistons have less difference of pressure on their two sides to work against, hence there is less packing-ring leakage encountered, and the pump runs cooler. Q. Is the low-pressure steam piston rod solid or hol- low? A. It is solid, and this piston, together with the high- pressure air piston, is called a floating piston. Q. Why are they called floating pistons? A. They perform no part in reversing the pump. Q. About how many cycles per minute should the pump speed be? A. About 65, and with 200 pounds of steam pressure it cannot be made to run any faster. Q. Then the pump cannot be raced? A. No, not even against a comparatively low air pres- sure, and it is practically impossible to create conditions which will result in any pounding. Q. With what steam pressures is this pump designed to operate? A. 160 pounds, or more. Q. How should it be started, drained, and lubricated? A. The same general rules given for the other pumps apply in operating the compound. WESTINGHOUSE PUMP GOVERNORS. The accompanying pump governor cut represents the old- style governor. Q. What does Fig. 42 illustrate? A. It shows a cross section of the old standard single pump governor, which has lately been superseded by the SF-4 du- plex type, described on page 143. This single governor is, however, still largely used. Q. Explain the duty of spring 41. A. The tension of the spring 41 is regulated by the cap nut 10 and holds down the diaphragm 42, which in turn holds the small pin valve on its seat. The fitting 45 is connected to main-reservoir pressure. When the pressure entering at 45 and acting on the under side of the diaphragm 42 is greater than the tension of the spring 41, the diaphragm is forced up, thus lifting the pin valve, from its seat. Q. What effect does unseating this pin valve have? A. It allows air pressure to reach the top of piston 28, (Fig. 42), forcing it down and closing valve 26. Q. What effect does closing valve 26 have? A. It almost shuts off the steam supply and slows down the pump, so that it operates very slowly. Q. Why does it not entirely stop the pump? A. A small port is drilled through valve 26, which al- lows a small amount of steam to pass through to the pump, thus causing it to operate slowly, thereby supplying the leak- age in the brake-pipe, and preventing the possibility of the pipes freezing in severe winter weather. Q. At the same time that air forces piston 28 down, where else does it go and with what effect? 140 Air-Be ake Catechism TO MAIN. RESERVOIR Ifff CONNECTION 26 ON ENGINEER'S BRAKE VAQVE Fig. 42. — Single Top Pump Governor, Pump Governors 141 A. It passes out of .the small vent port, at which the arrow 37 points, to the atmosphere. Q. What is effected by any reduction of the main reser- voir pressure? A. Any reduction of main-reservoir pressure allows the spring 41 to force the pin valve to its seat, and what air still remains on top of piston 28 escapes through the vent port 37, and, with no pressure on top of piston 28, the spring 31 raises the piston 28 and valve 26, allowing full steam pressure from the boiler to reach the pump. Q. Of what use is the spring under the head of the pin valve? A. To hold the valve up when piston 43 is raised. Were it not for the spring, the pin valve would remain seated by gravity. Q. If any air should leak by piston 28, or any steam should leak by the stem of the valve 26 into the cavity under piston 28, how would it escape? A. There is an opening in the casing 32 connected to a drip pipe which leads to the atmosphere. Q. What effect would be noticed if this drip pipe be- came clogged with dirt or were frozen shut, when there was a leakage of steam up under the governor piston? A. Piston 28 could not be forced down, and the pump would not stop working until the main-reservoir pressure was about equal to boiler pressure. Q. What would be the effect ?i the release port 37 (Fig. 42) were closed by dirt? A. The pump would be very N slow in starting to work after once stopping. Q. Why? A. Because, when the pin valve closed, the cavity above piston 28 would be filled with main-reservoir pressure, which 142 Air-Brake Catechism could escape only by leaking by the packing ring 29 and out to the atmosphere through the drip pipe. Q. What effect would dirt on the seat of the pin valve have? A. It would make a constant blow out of the vent port, and if air could leak in faster than it could get out of the vent port, the pump would either stop or work very slowly, even if the pump throttle were wide open. Q. Why would it work slowly? A. Because the pressure on piston 28 may force the valve 26 partly shut and allow only a small amount of steam to reach the pump. If the leak were bad enough, the pump would be stopped entirely. Q. What effect would be noticed if the pin valve be- came gummed so that it would not seat centrally? A. Air would pass down on piston 28, and the ac- tion of the pump would be the same as just described, with dirt on the seat of this valve. Q. What would be the effect if the casing in which the governor piston works should become badly worn, and a worn ring 29 were replaced with a new one without truing the casing? A. When piston 28 was forced down a little farther than usual, it might stick, causing the pump to stop. A jar on the governor might start the pump. . Q. Why was this type of governor superseded by the SF-4 type? A. So as to obtain the beneficial results of the duplex main-reservoir regulation in all equipments. This arrange- ment is described on page 174. Q. Is there any difference with these two governors in the principle of governing the pump? A. No; the only difference is that the pump can be i -MR MAIN RESERVOIR FEED- VALVE ATMOSPHERE LIVE STEAM WASTE STEAM AT PRESSURE PRESSURE FROM BOILER PRESSURE ATMOSPHERIC PRESSURE ■■—The SF-4 Pump Governor. The modified duplex pump- governor used in the No. 6 E T locomotive-brake equipment. MR— main-reservoir pipe, direct; ABV— pipe to automatic brake- valve; FVP— branch of feed valve pipe; B— steam pipe to boiler ; P— connection w ith air pump ; W— waste-pipe connection. Copyright, 1909, by The Norman W. Henley Publishing Co. Pump Governors 143 automatically governed at two different pressures, depending on the position of the brake-valve handle. The Present Standard (SF-4) Pump Governor. Q. What is represented in Fig. 43? A. The new duplex pump governor, used with all present standard locomotive brake equipments. Q. Of what does the duplex governor consist? A. Of two pressure heads which operate in conjunction with one steam portion of the governor. The former type of duplex governor was made by unscrewing the entire pres- sure head from the cylinder cap 27, Fig. 42, and replacing it with a "siamese fitting," No. 14, Fig. 43, which was arranged for two pressure heads, both just alike, and placed side by side. Q. In what respect does this SF-4 type of duplex gov- ernor differ from the former standard? A. One of the pressure heads has two air connections and an excess-pressure regulating spring; in operation this head automatically maintains the excess-pressure for which it is adjusted, regardless of what the brake-pipe pressure may be. Q. At what point is the additional air connection made? A. To the side of the upper portion above the diaphragm 28. Q. What pressure is always in the upper part of the excess-pressure head? A. Brake-pipe pressure. Q. What pressure is in chamber d under diaphragm 28? A. When the handle of the automatic brake valve is in 144 Air-Brake Catechism release or running positions, main-reservoir pressure is in this chamber. Q. When the brake-valve handle is not in running or release positions, what happens? A. The excess-pressure head is cut out of operation, the pump then being under the control of the other pressure head. Q. What is the other pressure head called? A. The "maximum-pressure" head. Q. What pressure is in chamber a under diaphragm 20, and when? A. Main-reservoir pressure, at all times. Q. When the brake-valve handle is in release or run- ning positions, and main-reservoir pressure is under both diaphragms, why does not the maximum-pressure head stop the pump? A. Because the regulation of spring 19 is for a higher pressure than is obtained in chamber d. This is fully ex- plained under Duplex Main-Eeservoir Eegulation on page 174. Q. Aside from the excess-pressure head and its air connection, is the SF-4 pump governor the same in con- struction, design and operation as the older standard du- plex pump governor? A. Yes, just the same. Q. Should care be exercised to keep all air connections tight and all ports in and around the governor open? A. In order to get satisfactory results all the pipe con- nections should be maintained perfectly tight and free from leakage, and all the vent ports should be kept open. Q. If any of the pipe connections should leak, what would be the result? A. A waste of air, the amount depending on the size of the leaks. Pump Governors 145 Q. How is the SF-4 pump governor adjusted to main- tain the proper excess pressure? A. By removing the cap nut on the excess-pressure top, and screwing down on the regulating screw 26 to increase excess-pressure; and by screwing up on this screw to reduce it. CHAPTEE V MAIN RESERVOIR Q. Where does the air go when it leaves the pump? A. To the main reservoir. Q. Where does main reservoir pressure begin and where end? A. It begins where the air leaves the primp and ends at the engineer's valve. Q. What is the object of the main reservoir? A. Its object is to act as a storehouse in which to keep a reserve pressure to put into the brake-pipe to release brakes and recharge auxiliaries. It also acts to collect most of the dirt, oil, and moisture that leaves the pump, and condenses as the air cools. Q. How much main reservoir pressure is usually car- ried? A. Usually ninety pounds, although more is used in moun- tainous country, when using the High-Speed Brake, the High-Pressure Control, or the Duplex Method of Main Ees- ervoir Eegulation. *■ Q. What size main reservoir is considered proper? A. One whose capacity is not less than 50,000 cubic inches for freight, and 40,090 or more for passenger engine, according to the kind of service in which the engine is placed. Best results are obtained in freight service by using a main- reservoir capacity of 70,000 cubic inches, where the trains are of considerable length. Main Reservoir 147 Q. How large should any main reservoir be? A. In releasing brakes in any service the main reservoir must be large enough so that, when the brakes are applied and we wish to release them, the main reservoir pressure will equalize with that in the brake-pipe, when connected with it, at a sufficiently high pressure to insure the prompt and certain release of the brakes. Q. Why is a larger main reservoir necessary in freight than in passenger service? A. Because there are a greater number of auxiliary res- ervoirs to charge in freight service and a longer brake-pipe to supply. Q. When is a large main reservoir with full pressure most essential? A. After an emergency application, and especially after a break in two. Q. What results are likely to follow the use of small main reservoirs on engines pulling long trains? A. The pump is likely to heat, brakes are likely to stick, we will have a hard handling rotary, and the recharge is ac- complished more slowly. Q. Why is a pump more likely to heat with a small main reservoir? A. Because the smaller the main reservoir, the higher the pressure has to be carried, and the higher the pressure the more is heat generated in compressing the air; therefore the pump is more likely to heat and burn out the packing. A second reason is that with a small reservoir, when re- leasing brakes, the pump must operate faster to charge the auxiliarjr-reservoirs before the speed of the train increases too much. The pump working very fast does not have time to take in a full cylinder of air each stroke ; it then makes more 148 Air-Brake Catechism strokes to compress the same amount of air, than it would were it working more slowly. Q. State the gains made by using a large main reser- voir? A. Pressure in the main reservoir and brake-pipe will equalize higher when releasing, auxiliary-reservoirs will be charged more quickly, the pump is not so likely to heat, and, not working so rapidly or against so high a pressure, will not wear out so fast, and the brakes are not so likely to stick. Q. What should be the location of a main reservoir? A. If possible, at the lowest point in the air-brake system. Q. Why? A. To have all the dirt, oil, and moisture possible drained into it and drawn off through the drain cock. Q. Where is the main reservoir usually located? A. On each side under the running board. Q. Should it be located there? A. Yes, when it is possible to place there a main reser- voir of the regulation size ; but the size must not be sacrificed for the position. Q. Is it right to locate it on the tank? A. Yes, if the requisite volume can be obtained in no other way; otherwise no. Q. Why is it not a desirable position? A. Oil and dirt will not drain into it as they should and when it is so located two extra lines of hose must run be- tween the tank and engine, one to carry the air from the pump to the main reservoir, and the other to bring the pres- sure from the reservoir to the engineer's valve. These hose get full of oil and dirt, decay, burst, and in the end prove very expensive. Q. How often should the main reservoir be drained? A. At the end of each trip. Main Reservoir 149 Q. Where does the water found in the main reservoir come from? A. It is drawn from the atmosphere, and deposited as the air cools. Q. Does any of the condensed steam from the steam :*2Pipe Thread Fig. 44. — Main Reservoir Drain Cock. end of the pump leak by the piston rod and then pass into the main reservoir with the compressed air? A. A trifle; but this is an inappreciable amount com- pared with what comes from the atmosphere, especially on rainy days. Q. What is generally conceded to be the best prac- tice concerning main reservoirs? 150 Air-Brake Catechism A. To use two main-reservoirs, preferably long and of small diameter, and a cooling pipe of approximately 25 feet between the pump and first reservoir, and 25 feet between the first and second reservoirs. Q. Why is this done? A. Tests have shown that, with these conditions existing, air cools properly before passing the brake valve and no water is found in the brake-pipe, thus doing away with the chance of frozen brake-pipes. The accompanying cut represents the drain cock for the main reservoir. This valve is screwed into the main reser- voir, and its operation is so simple that an explanation will be unnecessary. WESTINGHOUSE (G-6) ENGINEER'S BRAKE VALVE Q. What was the first form of valve used? A. That which was known as the old three-way cock. Q. With what equipment was this used? A. With the straight air, with the plain automatic, and for a time, by a good many roads, with the quick-action brake. Q. What objection, was there to it? A. It was not sufficiently sensitive, and there was great danger of throwing the brakes into emergency. Q. Why? A. Because reductions of brake-pipe pressure were made by instinct or sense of sound. An engineer having a short train to-day and a long one to-morrow could scarcely avoid doing poor braking, as his valve was nothing much more than a plug valve. A reduction that was a trifle too heavy would G-6 Engineer's Brake Valve 151 throw the triples into quick action, and on a long train the reduction could not be made too slow, or the air would blow through the leakage grooves in the brake cylinders. If the escape of air from the brake-pipe were suddenly checked, the air from the rear rushing ahead has a tendency to kick off some of the head brakes. Q. In changing the valve what was the object? A. To obtain a valve that would mechanically and grad- Fig. 45. — Showing Flow of Aie through Brake Valve when in Full Release Position. ually make the desired reduction of brake-pipe pressure, re- gardless of the length of the train. Q. Explain the different parts of the engineer's brake valve. 152 Air-Brake Catechism A. Y , T , W, and R are explained by referring to Figs. 46, 47, and 48 ; X connects with the main-reservoir. 31 and 32 are known respectively as upper and lower body gasket. 14 is the rotary valve. TO GAUGE BLACK HAND PE PRESSURE W I V\ PIPE TAP Y% PIPE TAP Fig. 46. — G 6 Engineer's Brake Valve, Release Position. 13 a gasket to keep main-reservoir pressure from leaking to the atmosphere. The space above piston 18 is known as cavity D; this cavity is connected with the little drum, or equalizing re- servoir, by the pipe 21. G-6 Engineer's Brake Valve DO 18 is the equalizing piston, 22 the brake-pipe exhaust. 3 is the rotary value seat, and l is the valve body. There is a tee in pipe 26 just after it leaves the valve, one branch of which goes to the red hand on the gauge and the other to the pump governor. The other parts need no naming. Fig. 47. — G 6 Engineer's Brake Valve, Running Position. Q. Of what use is the engineer's valve? A. To give the engineer complete control of the now of air. 154 Air-Brake Catechism Q. How many positions are there for the engineer's valve? A. Five. Q. Name them. A. Release, running, lap, service, and emergency posi- tions. TO PUMP GOVERNOR & GAUGE £ «o RED HAND I MAIN RESERVOIR PRESSURE Fig. 48. — G 6 Engineer's Brake Valve, Plan VieWo Q. Describe the use of the different positions. A. Release is that used for releasing brakes. Running position is the one used when running on the road and when the brakes are inoperative. Lap position is that which blanks all ports in the valve. Service is the position used when the brakes are to be applied gradually. G-6 Engineer's Brake Valve 155 Emergency is the position used when the brakes are to be applied suddenly and with maximum power. Q. What connections do we have with the valve in release? A. A direct connection between the main reservoir and brake-pipe through a large port, and between the main res- ervoir and cavity D, or the little drum, through two small ports. Q. Explain the flow of air from the main reservoir through the engineer's valve in this position. A. In this position the main-reservoir pressure enters the valve at X, passes through port A, port a of the ro- tary 14, port b of the rotary seat 3 (Figs. 45, 46 and 48), up into cavity c of the rotary and through port I into the brake-pipe at Y. As the air passes through cavity c of the rotary on its way to the brake-pipe, it is free to pass through port g (Fig. 46) into cavity D. In this position, port j of the rotary (Fig. 51) is over port e in the rotary seat (Fig. 46) also leading to the little drum, or cavity D. Q. Can main reservoir pressure reach the top of the rotary 14 at all times? A. Yes. Q. What is the valve shown in Fig. 45? A. It is the top portion of the old D 8 Brake Valve, a cut of which is inserted to convey a better idea of the flow of air through the brake valve in release position. Q. Does the passage of air through D 8 correspond to that of the G 6 Brake Valve in release position? A. Although the valves are somewhat different in con- struction, the flow of air in release position is practically the same in both brake valves. Q. How much main reservoir pressure is usually car- ried except in very mountainous country? 156 Air-Brake Catechism A. Ninety to one hundred pounds; in the description of the valve it will be considered that 90 pounds is used. Q. How much pressure would we get in the main reser- voir, the brake-pipe and the little drum, were the handle of the engineer's valve to be left in full release position until the pump stopped? A. Ninety pounds in each, as there is a direct con- nection between the three. Q. What is the small blow we hear if the engineer's valve is allowed to remain in full release? A. It is the escape of main-reservoir pressure through the warning port of the rotary into the emergency exhaust (Fig. 48) and out to the atmosphere. Q. What is this port and its purpose? A. It is a port, one end of which is about as large as a pin. When the engineer hears this blow it means to him that he must be careful or he will get ninety pounds pres- sure in the brake-pipe if he leaves the handle of his valve in full release position too long. Q. How much pressure is usually carried in the brake- pipe and little drum in country not mountainous? A. Seventy pounds. Q. How does the engineer prevent a ninety-pound pressure accumulating in the brake-pipe and little drum? A. By moving the valve to the second, or running posi- tion. Q. Why do we get only seventy pounds pressure in the brake-pipe with the valve in running position? A. Because in this position all air passing into the brake- pipe from the main reservoir has to pass through the feed valve (Fig. 47), and this is adjusted to close as soon as there is a seventy-pound pressure in the brake-pipe. G-6 Engineer's Brake Valve 157 Q. In running position we have the position of the rotary as shown in Fig. 47. Explain the passage of air in this position. A. The main-reservoir pressure passes through the ports L f and /' (Fig. 47 and 51) into the feed valve, or brake- pipe governor as it is more commonly called; thence through port i (Fig. 48) into port I (Figs. 46 and 48) and out into the brake-pipe at Y. As the pressure passes through port I into the brake-pipe it is also free to pass up into cavity c of the rotary, which is still over port I, as seen in Fig. 47. Port g is still exposed under cavity c, and at the same time the air passes through the brake-pipe governor into the brake- pipe, it also passes into cavity c of the rotary, port g of the rotary seat (Fig. 47) and into cavity J), or the little drum. Q. The brake-pipe governor closes when there is sev- enty pounds in the brake-pipe with the valve in running position. How much pressure do we get in the main reser- voir with the valve in this position? A. Ninety pounds. Q. What stops the pump when there is ninety pounds in the main reservoir? A. The pump governor, which is connected with main- reservoir pressure at 26 (Fig. 46). Q. Is the pump governor always set at ninety pounds? A. No ; only in level and hilly country. In mountainous country, it is set much higher, also in level country where exceptionally long trains are handled. Q. The red hand on the gage represents main reser- voir pressure, and the black hand is said to represent that on the brake-pipe. Is the pipe leading to the black hand connected directly to the brake-pipe? A. No ; it is connected to the little drum pressure. (See 21, Fig. 46.) 158 Air-Brake Catechism Q. Why is it called brake-pipe pressure if not connect- ed to it? A. Because in full release or running position port eed. 45 Stop High-Speed. 560 in. Feet. Quick Action 710 Quick Action Per Cent. Less Efficient. 26.8 Feet in Favor of High-Speed Brake. 150 50 705 880 24.8 175 60 1063 1360 28.3 300 70 1560 2020 29.5 460 80 2240 2780 24.1 540 Brake-pipe pressure used with High-Speed Brake, 110 pounds. Brake-pipe pressure used with Quick-Action Brake, 70 pounds. The above table refers to stops made with chilled cast-iron wheels and soft cast-iron shoes with a train which was sup- posed, to represent average conditions of service. Hand Brake Straight Air 1869 Plain Automatic 1872 Quick Action Automatic 1887 Hi?h-Speed Brake- 5 1894 New Type"L" Equipment 1908 New Type "L" Equipment 1908 , 80 LBS. IB. P.P. 1 ! t 1 1 l 500 1000 1500 2000 2500 3000 LENGTH OF STOP - FEET Fig. 62. — Progress of Ate Brake Efficiency as Shown by Com- parative Distances in which Trains are Stopped. Double Pressure Control Equipment 189 DOUBLE PRESSURE CONTROL EQUIPMENT OR SCHEDULE U. Q. What does Fig. 62-A on page 190 represent? A. The Double-Pressure Control or Schedule U Equip- ment sometimes used on freight engines. Q. How does it differ from the old style high-speed en- gine equipment? A. Instead of high-speed reducing valves, a safety valve is placed in the tender brake cylinder head, and another in the pipe between the driver-brake triple valve and cylinders. Q. What is the object of this special equipment? A. It is designed for special use on roads having heavy grades and handling loads, such as ore, down the grade, and empty cars up. Q. What special advantage is gained? A. By using two feed valves which are usually set for 70 and 90 pounds, either one of these pressures can be used in the brake-pipe and 90 or 110 pounds can be used in the main reservoir, when the brake-valve handle is in release or running positions. Q. Would there not be danger of sliding wheels if 90 pounds were used as brake-pipe pressure? A. Possibly if used on empty cars; but if used on heavily loaded cars, there would be no danger, as the highest possible braking power is usually 70 to 80 per cent, of the light weight of the car, and when loaded to its full capacity, the percentage of braking power, as compared with the combined weight of the car and its contents, is much smaller than this, even when using a brake-pipe pressure of 90 pounds. Q. How much more powerful would a brake be when 190 Double Pressure Coxtrol Equipment 191 using a brake-pipe pressure of 90 pounds as compared with 70? A. Approximately 25 per cent. Q. With the cocks as shown in Fig. 62-A, which feed valve is operative? A. The 70-pound feed valve. Q. What benefit is derived from this device when the 70-pound feed valve is cut in? A. With the brake valve in running position, the pump does not have to work against a higher pressure than 90 pounds, but just as soon as the brakes are applied the pump raises the pressure in the main reservoir to 110 pounds, which pressure is very helpful to insure a quick release on a long train and quickly recharge the auxiliaries. Q. What would be done in case the cars were all heav- ily loaded and it was desired to use a brake-pipe pressure of 90 pounds and a minimum main-reservoir pressure of 110 pounds? A. The reversing-cock handle would be moved so as to cut out the 70-pound feed valve and cut in the 90-pound feed valve. Q. Would it be safe to use the 90-pound brake-pipe pressure when there were air brakes on both light and loaded cars in operation in the same train? A. While there is a chance that a little wheel sliding might result if an emergency or very heavy service reduction were made, the likelihood of serious sliding is so slight that it is not customary to cut out empty cars and thus lose their brak- ing power. Q. When using a 90-pound brake-pipe pressure, is the same brake-pipe reduction necessary to apply the brakes in full as is used with a 70-pound brake-pipe pressure? A. No ; a heavier reduction would be necessary. iya Air-Brake Catechism Q. How much of a brake-pipe reduction would equalize the auxiliary-reservoir and brake-cylinder pressures, using an initial pressure of 90 pounds? A. About 27 pounds, if the piston travel were approximate- ly eight inches. Fig. 63. — Old Style Safety Valve. Fig. 64. — New Style Safety Valve. Q. Why are safety valves placed upon the tender, driver, and truck brakes? A. So as to allow all pressure over 50 pounds to escape to the atmosphere. Experience shows that over-heating of tires is likely to ensue if a greater pressure than this is used on the tender, driver or truck brakes. Combined Automatic and Straight Air 193 Q. What is best to use on the engine if the grade is very long and heavy and the speed slow? A. A water brake. With this brake no heating of tires is produced, as the braking is done with the pistons in the main cylinders. Q. With a brake-pipe pressure of 90 pounds, is any more braking power developed with a 5, 10 or 15-pound service reduction than if 70 pounds was carried on the brake-pipe? A. No; no gain will be made unless brake-pipe reduc- tions are continued after the point has been reached at which the reservoir and brake cylinder pressures would equalize when using the 70-pound brake-pipe pressure. Q. Why is this? A. Because, if calculated, it will be found that it re- quires the same number of cubic inches of free air to raise the auxiliary-reservoir pressure from 50 to 70, 70 to 90, or 200 to 220 pounds. If the same amount of air is used in each case, the same pressure would result if 20 pounds were taken from the auxiliary, when containing any pressure above 70 pounds, and put into the brake cylinder if the piston travel were not less than 8 inches. WESTINGHOUSE OLD-STYLE COMBINED AUTOMA- TIC AND STRAIGHT AIR-BRAKE EQUIP- MENT FOE ENGINES AND TENDEES. Q. For what purpose was this equipment designed? A. For use on engines and tenders in yard and freight service. Q. Why is it necessary on yard engines with old style equipment? A. Because an old-style triple valve will not recharge the 194 " f ? 5 < « "A w W p fe w M H <3 Q 'A H «j O H s M rt H rn Q H £ w ePtP£ TAP Fig. 78. — Interior Views of the S-6 Independent Brake Valve. ET Locomotive Brake Equipment 225 leading to the application cylinder of the distributing valve, is open to the atmosphere through exhaust port g in the rotary and central exhaust port h in the seat, so that the air can escape from the application cylinder, thus permitting the brakes to release. Q. When the handle is placed in release position, will it remain there if the hand is removed? A. No, it will be returned automatically to running po- sition by return spring 6. Q. Where should the handle be carried when the in- dependent valve is not in use? A. Always in running position. Q. What is the relation of the ports in running posi- tion? A. In running position port a and port c in the rotary seat are in communication through passage / in the rotary, so that air from the distributing- valve exhaust may pass through the independent brake valve to the automatic brake valve, where it can escape to the atmosphere, when the handle of the latter is in running position. Q. Why are ports a, c, and passage f so arranged? A. To enable the engineer, whenever operating the auto- matic brake, to hold the locomotive brake applied when re- lasing the automatic brakes; that is, to enable him to con- trol the escape of air from the application cylinder when re- leasing. Q. How are the brakes applied independently? A. By moving the handle to either application position and admitting air to the application cylinder. Q. How are the ports arranged in slow application position? A. Supply port b and service port d are connected by the 226 Air-Brake Catechism circular cavity e and small port m, and air can flow from the supply direct to the application cylinder. Q. How are the ports arranged in quick application position? A. Ports b and d both connect with cavity e, giving a more rapid flow of air from the supply to the application cylinder than in slow application position. Q. What is lap position for? A. To blank all ports when the brakes have been applied independently with the desired degree of force. Q. What is the maximum brake-cylinder pressure ob- tainable with the independent brake valve? A. Forty-five pounds. Q. Why is this? A. Because the air that comes from the main reservoir to the independent brake valve must first pass through a pressure-reducing valve, adjusted at 45 pounds; this valve is located in the main-reservoir pipe at a point before it reaches the independent brake valve. Q. Trace the air through the independent brake valve *? A. Air from the main reservoir, reduced in pressure to 45 pounds, enters the brake valve, at the supply connection, Fig. 78, passes up through port b in the seat to. the circular cavity e in the face of the rotary and through the port at the right hand end of this cavity to the top of the rotary. There is always independent-brake pressure, 45 pounds, on top of the rotary with the handle of the brake valve in any of its positions. With the handle in application position, port b and port d are connected by the cavity e (and port m), and air can flow into application cylinder pipe to the application cylinder of the distributing valve to apply the brakes. With the handle in lap position communication be- tween the various ports is cut off and air cannot flow in ET Locomotive Brake Equipment 227 any direction through the valve. With the handle in run- ning position, the passage / in the rotary connects port a from the distributing-valve exhaust, and port c, the latter leading to the automatic brake valve, so that when the handles of both valves are in running position the air may escape from the application cylinder to the atmosphere and release the brakes. With the handle in release position, cavity g in the rotary connects port d with the central ex- haust port h leading to the atmosphere. Q. When is it necessary to use the release position of the independent brake valve in order to release the loco- motive brakes or reduce the brake-cylinder pressure? A. Only when the handle, of the automatic brake valve is not in running position. Q. If it is desired to remove the brake valve for clean- ing or repairs, what is it necessary to do? A. Unscrew the nuts from bolts" 21 and take the valve off its base. Q. How is the valve taken apart to get at the interior parts? A. Unscrew the cap screw 28, the cover screws 19, and .the nut 14, and all parts of the valve may be separated. Q. What is the function of the spring 11? A. It keeps the key washer 12 and the rotary- valve key 10 up from the rotary and makes the washer press against the valve body 4, thus preventing leakage by the rotary-valve key when the pump is first started. It also serves to hold the rotary on its seat when there is no pressure and thus prevents dirt from getting on the valve seat. Q. With the independent brake valve, can the locomo- 228 Air-Beake Catechism tive brakes be applied and released under any and all con- ditions of service? A. Yes, they can be controlled perfectly with the inde- pendent brake valve under all conditions of service. Q. When the engine is standing alone on ash pits, turntables, or sidings, and when doing work about the engine, should the independent brake valve be applied and left applied? A. Yes, this practice should be followed at all such times. Q. Why is it important to do this? A. To avoid possibility of the locomotive moving when not desired, as from a leaky throttle or other cause. » THE NO. 6 DISTRIBUTING VALVE. Q. What do Pigs. 79 and 80 represent? A. They represent the distributing valve and reservoir, showing its general appearance, pipe connections, and also the double chamber reservoir, with its pressure chamber and application chamber. Q. Name the pipe connections to the distributing valve, and describe them. A. Referring to Fig. 79, the connection marked "MR" is the supply-pipe connection. The supply pipe connects the main-reservoir pipe and the distributing valve. The connection marked "IV" is the distributing valve release pipe, and connects the exhaust port through the equalizing slide valve of the distributing valve with the independent brake valve, and when the latter is in running position, ex- tends through it to the automatic brake valve. The inter- mediate connection marked "II" connects the application PRESSURES I I czz 1 L MAIN ATMOSPHERIC PRESSURE RESESVOIR CHAM3ER Fig. 78 a I g|. — No. 6 Distributing Valve in Released and Charging Position. Copyright, 1 909, by The Norman W. Henley Publishing Co. ET Locomotive Brake Equipment 229 cylinder to the independent brake valve, and to the auto- matic brake valve. Referring to Eig. 80, the upper connection is the one that connects the distributing valve to the brake cylinders. The Fig. 79. — Distributing Valve and Double Chamber Reservoir. lower connection is the one between the brake pipe and the distributing valve. Q. What is the function of the distributing valve? A. To -admit air to, and to exhaust it from, all the brake Fig. 80. — Distributing Valve and Double-Chamber Reservoir. 230 Air-Brake Catechism cylinders on the locomotive, both in automatic and in in- dependent applications, and to maintain automatically the desired cylinder pressure regardless of cylinder leakage and variation in piston travel. Q. What are the purposes of the cut-out cocks in the brake-cylinder pipe? MR ;W Fig. 81. — Release Position — Automatic or Independent. ET Locomotive Brake Equipment 231 A. In case it is desired to cut out any one or all of the brakes for any cause, such as burst hose or broken down brake rigging, they may be closed to prevent the brakes from applying. Q. Should the hose burst either in front of the engine- truck brake or of the tender-brake cylinder during a MR 43 Fig. 82. — Independent Application, 232 Air-Brake Catechism brake application, would the other brakes release? A. No. Q. Why is this? A. Because of the special choke fittings (Fig. 71) in the end of the cut-out cocks toward the brake cylinder, which prevent air from passing through them faster than the dis- tributing valve can supply it. MR ^\\\\\\\\\\^v^\\\\\\\\\\\\\\^^^^ -43 Fig. 83. — Independent Lap. ET Locomotive Brake Equipment 233 Q. What is the standard brake-pipe pressure carried with the ET brake? A. For the ordinary brake 70 pounds; for the high- speed brake 110 pounds; and for the double-pressure control 90 pounds. Q. What does Fig. 91 represent? MR -43 Fig. 84. — Automatic Sertice. 234 Air-Brake Catechism A. It is a sectional drawing showing the interior of the distributing valve as actually constructed. Q. Keferring to Figs. 80 and 91, what are the names of the parts as numbered? A. The proper names of the different parts of the dis- tributing valve are as follows: 2, Body; 3, Application-Valve Cover; 4, Cover Screw; 5, Application Valve; 6, Application- MR Z^ h43 Fig. 85. — Service Lap. ET Locomotive Brake Equipment 235 Valve Spring; 7, Application-Cylinder Cover; 8, Cylinder- Cover Bolt and Nut; 9, Cylinder-Cover Gasket; 10, Appli- , cation Piston; 11, Piston Follower; 12, Packing Leather Expander; 13, Packing Leather; 14, Application-Piston Nut; 15, Application-Piston Packing Eing; 16, Exhaust Valve; 17, Exhaust- Valve Spring; 18, Application- Valve MR -43 Fig 86.— Emergency. 236 AiRrBEAKE Catechism Pin; 19, Graduating Stem; 20, Application-Piston Gradu- ating Spring; 21, Graduating-Stem Nut; 22, Upper Cap Nut; 23, Equalizing Cylinder Cap; 24, Cylinder-Cap Bolt and Nut; 25, Cylinder-Cap Gasket; 26, Equalizing Piston; 27, Equalizing-Piston Packing Eing; 28, Graduating Valve; 29, Graduating-Valve Spring; 31, Equalizing-Slide Valve; 32, Equalizing Slide-Valve Spring; 33, Lower Cap Nut; 31, MR wv. 1 ~ zi Fig. 87. — Emergency Lap, ET Locomotive Brake Equipment 23' Safety Valve; 35, Double Chamber Eeservoir; 36, Reservoir Stud and Nut; 37, Eeservoir Drain Plug; 38, Distributing- Valve Drain Cock; 39, Application- Valve Cover Gasket; 40, Application-Piston Cotter; 41, Distributing Valve Gasket (not shown); 42, Oil Plug; 43, Safety- Valve Air Strainer; MR Fig. 88. — Independent Release when Brake has been Applied Automatically. 238 Air-Beake Catechism 44, Graduating Sleeve; 45, Cylinder-Cap Nut; 46, Equaliz- ing-Piston Graduating Spring. Q. What do Figs. 81 to 89 inclusive represent? A. They are diagrammatic drawings that represent the distributing valve in all of its different operative positions. Q. Name these positions. A. They are, Fig. 81, Release, Automatic or Independent; MR V.-': '''" ' Fig. 89. — Emergency, when the Quick-Action Cap is Used. ET Locomotive Brake Equipment 239 PLAN OF GRADUATING VALVE FACE OF SLIDE VALVE '"if"" N IjL.^ J :_) j v — j. q _0_{ r j fi si_ PLAN OF SLIDE VALVE h 0' "0 0> PLAN OF SLIDE VALVE SEAT Pig. 90. — Graduating Valve, Equalizing Slide Valve and Slide Valve Seat. 240 Air-Brake Catechism Fig. 82, Independent Application ; Fig. 83, Independent Lap; Fig. 84, Automatic Service; Fig. 85, Service Lap; Fig. 86, Emergency; Fig. 87, Emergency Lap; Fig. 88, Eelease Position, when locomotive brake is released by in- dependent brake-valve after an application by brake-pipe re- duction ; Fig. 89, Emergency Position, when the quick- action cap is used. Q. What is represented in Fig. 90? A. Fig. 90 represents the plan of the graduating valve, shows two views of the slide valve, face and plan, and a plan of the slide valve seat. These views show the arrangement of ports as they act- ually are constructed, and are not diagrammatic drawings. Q. How does the distributing valve charge up the pres- sure chamber of the double chamber reservoir? A. In precisely the same manner that a triple valve charges an auxiliary reservoir; that is, by referring to Fig. 81, brake pipe air enters the distributing valve at BP , fills chamber p, and flows through the feed groove v at the top of piston 26 to the slide valve side of this piston, and thence to the pressure chamber through port o until the pressure in this chamber is equal to that in chamber p and the brake pipe. Q. Then the pressure in the pressure chamber, when fully charged, is equal on both sides of piston 26? A. Yes. INDEPENDENT APPLICATION. Q. What takes place in the distributing valve when the handle of the independent brake valve is placed in service position? A. As shown in Fig. 82, air is admitted directly from ET Locomotive Brake Equipment 241 this valve to the application cylinder, forming a pressure therein which causes the application piston 10 to move for- ward compressing spring 20, until stopped by the graduating stem 19. This in turn moves the brake cylinder exhaust valve 16, and the application valve 5, over until the former closes the brake cylinder exhaust port and the latter opens its port. Under these conditions main-reservoir air from chamber a is free to flow to the brake cylinders through chamber b and port c. Q. After the pressure in the brake cylinders becomes slightly greater than that in the application chamber what takes place? A. The application piston 10 and the supply valve are moved by the excess pressure and the spring 20 to the inde- pendent lap position, as shown in Fig. 83. The movement of the piston is stopped by its striking the exhaust valve 16, which does not move. Q. How is this valve made to assume this position? A. When the pressure in chamber b is slightly greater than that in the application cylinder, piston 10 and appli- cation valve 5 move back until valve 5 laj3S its port, where further flow of main-reservoir air to the brake cylinder is cut off, and the brake remains applied with a pressure equal to or slightly in excess of that in the application cylinder. Q. Suppose that after application valve 5 moves to lap position, leakage of air from the brake cylinders should cause the pressure therein to fall, what would occur? A. , As soon as the pressure in chamber b fell slightly below that in the application cylinder, the application piston 10 would be forced to the right and application valve 5 would open its port and admit main-reservoir air again to supply the leakage and raise the brake-cylinder pressure practically 242 Air-Brake Catechism equal to that in the application chamber and the application cylinder, then move back to lap. Q. How are the brakes released after an independent application? M.R, CYLS. -B.P* Fig. 91. — Distributing Valve Showing Connections. A. By placing the handle of the independent brake valve in running position, when the air in the application cylinder will escape to the atmosphere ; the pressure in chamber b will then force the application piston and both valves to release ET Locomotive Brake Equipment 243 position, as shown in Fig. 81, and brake-cylinder air will then escape to the atmosphere through the exhaust ports in exhaust valve 16, and in the body of the distributing valve. Q. What position must the handle of the automatic brake valve be in that the air may escape from the ap- plication cylinder when the handle of the independent brake valve is in running- position? A. In running position. Q. Does the equalizing" piston 26 and its attached parts operate during an independent application and release? A. No; they remain inoperative, as shown in Figs. 81, 82 and 83. AUTOMATIC OPERATION". Q. How is an automatic service application of the brake made? A. By moving the handle of the automatic brake valve to service position and making the desired brake pipe reduction. Q. When a reduction in brake-pipe pressure takes place, what happens in the distributing valve? A. With the pressure chamber charged equal to that in the brake pipe, a reduction in brake pipe pressure causes equalizing piston 26 to move to the right (Fig. 84), carry- ing with it slide valve 31 until the knob on the piston strikes the graduating sleeve 44, which closes the exhaust port lead- ing from the application chamber to the distributing-valve release pipe, and the graduating valve 28 is moved to the right until it uncovers the service port z, which leads into passage h and the application cylinder, and through cavity n and port w to the application chamber, thus allowing air from the pressure chamber to flow into the application 244 Air-Brake Catechism cylinder and chamber. The pressure thus formed in the appli- cation cylinder and chamber causes the application piston 10, exhaust valve 16, and application valve 5 to assume the posi- tion shown in Fig. 84, "Automatic Service/' and apply the brakes. When the pressure in the pressure chamber falls slightly below that in the brake pipe, equalizing piston 26 moves back, carrying with it the graduating valve 28, without moving slide valve 31, until the graduating valve closes port z, and prevents any further flow of air from the pressure chamber to the application chamber. It is then in '"Service Lap" position as shown in Fig. 85. Q. How much of a brake-pipe service reduction is re- quired to set the brake in full? A. About 20 pounds, the same as with a triple valve. Q. How is the brake released by the automatic brake valve? A. An increase of brake pipe pressure raises that in chamber p (Fig. 85) of the distributing valve. This pres- sure being greater than that in the pressure chamber of the distributing valve, forces piston 26, and the parts controlled by this piston, to the left. In this position the pressure from the application cylinder and the application chamber is free to now through port h and the independent brake valve to the automatic brake valve, from whence it may escape to the atmosphere when the brake valve handle is in running posi- tion. The escape of the pressure through port h, connected with the applicaton cylinder, reduces the pressure in this cylinder and permits the greater pressure in chamber b to force piston 10 to the left; it in turn draws the parts attached to it to a corresponding position (Fig. 81). In this position brake- cylinder pressure escapes to the atmosphere through ports ET Locomotive Brake Equipment 245 d and e in the seat of the slide valve 16 and the brakes on the locomotive release. <> Q. How is an automatic emergency application made? A. By making a quick, heavy brake-pipe reduction, when the equalizing piston 26, with equalizing slide valve 31, and graduating valve 28, will move their full stroke with suf- ficient force to compress the graduating spring 46, strike against the gasket 25, and open port h wide to the applica- tion cylinder without opening port w to the application chamber, as shown in Fig. 86, permitting full equalization between the pressure chamber and the application cylinder only, which, being very small in volume compared to the pres- sure chamber, will equalize at a much higher pressure than when the application chamber is connected to the application cylinder; thus applying the brakes with a much greater force than in a full service application. Q. Are there any other times when the application chamber and application cylinder are not connected? A. No; only in emergency applications. Q. From what other source is air pressure supplied to the distributing valve in emergency applications? A. When the handle of the automatic brake valve is in emergency position, main-reservoir air feeds through ports in the rotary valve and seat to the application-cylinder pipe, and thence directly into the application cylinder of the dis- tributing valve through port h. Q. How much pressure is obtained in the application cylinder and the brake cylinders in an emergency applica- tion? A. Assuming the brake-pipe pressure to be 70 pounds, about 65 pounds is had in the brake cylinders. Q. How is this additional 15 pounds obtained? A. By the higher equalization of application cylinder and' pressure chamber, and the maintaining of the resulting 246 Air-Brake Catechism pressure by the flow of main-reservoir air through the brake valve and ajmlication-cylinder pipe. Q. What provision is made to prevent too high a pres- sure in the brake cylinder? A. The safety valve, as shown in Fig. 86, is connected through ports in the equalizing slide valve to the application cylinder, and when the pressure becomes higher than its limit of adjustment (68 pounds) it opens and vents the surplus air to the atmosphere. Q. What is the emergency lap position of the distribut- ing valve? A. It is the position shown in Fig. 87, in which the amplication piston 10 and application valve 5 have been moved back by excess pressure and graduating spring 20 far enough to close the port in the supply valve and prevent further flow of main-reservoir air to the brake cylinders. Q. What does Fig. 88 illustrate? A. It illustrates the positions of the various valves in the distributing valve after an automatic application, and then an independent release have been made. Q. In what kind of application do the equalizing piston 26 and the slide valve 28 and 31 operate? A. In all automatic applications of the brake both serv- ice and emergency. Q. How much pressure can be had in the brake cylin- der in a full service application? In an emergency? A. When the brake-pipe pressure is 70 pounds, about 50 pounds, the same as with the present brake in a service ap- plication. In an emergency application the cylinder pres- sure would approximate 65 pounds. Q. Suppose the high-speed-brake pressure of 110 pounds is being used, how much will be had in the ap- plication cylinder in an emergency application? ET Locomotive Brake Equipment 247 A. About 90 pounds; the same will be had in the brake cylinders, and these pressures will gradually be reduced to 68 pounds by the safety valve. Q. Is it necessary to break any pipe joints when re- moving the distributing valve from the double-chamber reservoir? A. No; all the pipe connections are made to the double- chamber reservoir proper. Q. Suppose it were desired to remove the application piston, how should this be done? A. The application-valve cover 3 should first be removed, then the application valve 5 and the application-valve pin 18 should be taken out, after which the application-cylinder cover can be removed and the application piston taken out for inspection and repairs. Q. What is the purpose of the small port u? A. It forms a passage for any water that may deposit in the cylinder to the right of the application piston to drain off into port m, where it runs to the bottom of the valve, and should be drawn off each trip by means of the drain cock 38. The Quick-Action Cylinder Cap. Q. What device is illustrated in Fig. 92? A. The quick-action cylinder cap. Q. With what valve is this used? A. The distributing valve. Q. What is the purpose of this cap? A. It furnishes a means of obtaining quick-action with the distributing valve the same as is obtained with a quick- action triple valve; that is, it vents a portion of the brake- 2^8 Air-Beake Catechism pipe pressure into the locomotive brake cylinders in emer- gency applications. Q. What effect has this on the train? A. It quickens the reduction of brake-pipe pressure, making it more certain that all quick-action triple valves in the train will go to emergency position. Fig. 92. — Quick-Action Cylinder Cap. Q. When is this cap used? A. In the same class of service that uses quick-action triple valves on the tender with the old standard locomotive brake. Q. It is not then a standard part of the ET equip- ment? A. ISo; only when conditions require it. ET Locomotive Brake Equipment 249 Q. When used, how is it attached to the distributing valve? A. The plain cylinder cap 23 is removed, and the quick- action cap put in its place. Q. Referring to Fig. 92, what are the parts of the quick-action cylinder cap? A. 44, Cylinder-Cap Body; 45, Stop Nut; 46, Graduat- ing Spring; 47, Bushing; 48, Slide Valve; 49, Check- Valve Nut; 50, Check- Valve Seat; 51, Check- Valve Nut; 52, Check- Valve Kubber Seat; 53, Check Valve; 54, Check- Valve Spring; 55, Graduating- Spring Nut; 56, Slide-Valve Pin; 57, Slide-Valve Spring; 58, Graduating-Stem Pin; 59, Graduating Stem. Q. Referring to Fig. 89, how does this cap operate? A. In an emergency application, equalizing piston 26 moves rapidly to the right, its knob striking graduating stem 59 and compressing the graduating spring, until it strikes the cylinder-cap gasket. The movement of the gradu- ating stem carries with it slide valve 48, and opens port j, allowing brake-pipe air to flow to cavity x, force down check valve 53 and flow through ports m and c to the brake cylin- ders on the locomotive. The other parts of the distributing valve operate exactly as already described for emergency ap- plications. As soon as the decreasing pressure in the brake pipe becomes equal with the increasing pressure in the brake- cylinder pipe, check valve 53 is forced to its seat by spring 54, and prevents any air flowing from the brake cylinders back into the brake pipe. When the brakes are released after an emergency application, piston 26 is forced to the release position, as already described, and the graduating spring forces graduating stem 59 and slide valve 48 to the position shown in Fig. 89, closing port j, and preventing brake-pipe air from flowing to the brake cylinders. 250 Air-Brake Catechism Q. How does it operate when automatic service ap- plications are made? A. The parts do not move; the graduating stem 59 forms the stop against which the equalizing piston strikes, exactly the same as graduating sleeve 44 in the plain cylinder caj:>. Q. What would occur if slide valve 48 leaked? A. There would be a slight blow at the brake-cylinder exhaust of the distributing valve in release. The Use of the Safety Valve. Q. What function does the safety valve, shown in Figs. 79 and 80, perform when attached to the distribut- ing valve? A. It performs all the functions of the ordinary brake cylinder relief valve and in addition those of the high-speed reducing valves. Q. What are the names of the different parts of this device? A. As shown in the illustration they are, 2, Body; 3, Cap Nut; 4, Valve; 5, Valve Stem; 6, Adjusting Spring; 1, Adjusting Nut. Q. Of what peculiar style or variety is this valve? A. It is known as the pop-valve style. Q. At what pressure is this valve usually adjusted when used in the ET equipment? A. At 68 pounds. Q. Explain its operation. A. The adjustment of the valve is effected by screw- ing down the regulating nut 7 until the adjusting spring has sufficient tension to hold valve 4, against the pressure it is desired to retain, after which the cap nut 3 is screwed on firmly in place. When the air pressure acting upward ET Locomotive Brake Equipment 251 on valve 4 is greater than the adjusting spring can re- sist, this valve will lift from its seat, exposing a slightly greater area to the pressure below, which causes it to move promptly the whole length of its travel, or until the stem strikes the cap nut, and allow the surplus air to escape through the two bottom ports in the body 2. Q. What is the object of the by-pass port that leads up into the chamber in the body 2 above valve 4? A. When valve 4 lifts to relieve pressure it travels far enough to cover the upper end of the by-pass port, thus pre- venting air in any considerable quantity from passing into the chamber above. When it commences to lower, it grad- ually opens this port, and closes the lower ports to the atmos- phere, allowing air to pass into the upper chamber, where it will then form a pressure above valve 4 and cause it to seat promptly. There are two relief ports in the chamber to allow the air remaining therein to escape after valve 4 closes ; while valve 4 uncovers the upper end of this by-pass port the two relief ports can not allow the air to escape so fast but that pressure will be formed in the upper chamber in the valve body. FEED VALVEIS. THE B-6 FEED VALVE. Q. What is Fig. 93? A. It is a photographic view of the exterior of the feed valve, used with the ET equipment, to regulate the pressure in the brake-pipe when the handle of the automatic brake valve is in running or in holding position. Q. How does this feed valve differ from the slide valve feed valve used with the G-6 brake valve? A. Its operation is the same except that ; by the use of 252 Aie-Brake Catechism the adjusting wheel it can be adjusted for the pressure desired. It is also different in detail, having a larger regulating valve a supply valve with a port in it, and a different supply valve piston. For description of its operation see G-6 Feed Valve. Q. What advantage does this adjusting feature give over that of the older feed valve? A. It makes it possible to dispense with one of the two Pig. 93.— B-6 Feed Valve. feed valves now used with the high-speed and the double- pressure control brakes, also the reversing cock bracket. Q. How is the adjustment of the B-6 feed valve effected? A. By turning the adjusting handle in one direction until the pin on it strikes the lower stop the valve will maintain 70 pounds brake-pipe pressure and by turning it in the other di- rection until the pin strikes the upper stop, it will maintain 110 pounds brake pipe pressure. ET Locomotive Brake Equipment 253 Q. If any other pressures than the above are desired, what must be done? A. The positions of the stops must be changed. THE C-6 REDUCING VALVE. Q. What kind of a reducing valve is used with the ET equipment? A. It is known as the C-6 and is practically the same as the B-6, except that it does not have the adjusting wheel of the former. For a description of its operation see G-6 Feed Valve. Q. At what pressure is it adjusted? A. At 45 pounds. Q. To what does this pressure reducing valve supply- air? A. It supplies both the independent brake and the train air signal. THE PUMP GOVERNOR. Q. What pump governor must be used with the ET equipment? A. The SF-4 pump governor. Q. To what is the upper part of the excess-pressure head connected? A. The feed-valve pipe. Q. What pressure is always in the excess-pressure head and the feed-valve pipe connection? A. Maximum brake-pipe pressure. Q. To what pressure is the maximum-pressure head connected? A. To the main-reservoir pressure direct. 254 Air-Brake Catechism Q. Explain the operation of the governor in this equip- ment. A. The connection marked A B Y , Fig. 43, has main-reser- voir air flowing through it into the excess-pressure top under the air diaphragm 28, when the handle of the automatic brake valve is in release, running, or holding position; and the connection marked F V P has air at maximum brake-pipe pressure flowing through it to the spring, case above the air diaphragm regardless of the position of the brake-valve han- dle. Assuming that the tension on the excess-pressure spring 27 is such that it requires an excess pressure of 20 pounds beneath the diaphragm to raise it against the air pressure bearing down upon it from above, the main-reservoir pres- sure must be 20 pounds in excess of that in the feed-valve pipe before the diaphragm can be lifted and the pump stopped. If the handle of the automatic brake valve is moved to service-application position, the communication between the main reservoir and chamber d of excess pressure top is cut off so that the pressure above the diaphragm will hold it down with the pin valve on its seat; this head cannot then control the pump. The pump will now work until the main-reservoir pressure reaches that for which the maximum-pressure head at the right is adjusted, say 130 pounds, when this head will operate in the usual manner and stop the pump. When the handle is moved to release, running or holding position, main-reservoir air may again flow to the excess-pres- sure head to chamber d under the diaphragm. When the brake-pipe pressure is restored to the maximum for which the feed valve is adjusted, and the handle of the brake valve is either in running or in holding position, the pump can work until the main reservoir has accumulated the proper excess, when the excess-pressure head will operate and stop the pump. ET Locomotive Brake Equipment 255 Q. In the piping diaphragm, Fig. 71, there is shown, placed in the main-reservoir pipe, a cut-out cock. At what point with relation to this cock is the maximum-pressure head connected to the main reservoir? A. It is connected between this cut-out cock and the main reservoir. Q. Why is it so located? A. So that in case it is necessary to close the cut-out cock to make repairs to any other part of the equipment, the maximum pressure top can still control the pump, and pre- vent it from pumping up an excessively high main-reservoir pressure. Q. What happens when this cut-out cock is closed? A. A port is so arranged that the air in the main-res- ervoir pipe and brake-pipe is vented to the atmosphere, re- sulting in an application of the brake. If the engineer fails to open the cock the brakes will not release and the train cannot be started. DEFECTS OF "ET" EQUIPMENT. Q. If the application cylinder pipe should leak at any of its connections between the distributing valve and the independent brake valve, what would be the effect? A. It would cause the brakes to leak off both in automatic service and in independent brake applications. Q. If the pipe connection between the independent and the automatic brake valves should leak, what would be the effect? A. The brake would leak off when the automatic brake- valve handle was in holding position, but not at other times. Q. Suppose the distributing-valve release pipe should leak at any of its connections between the distributing 256 Air-Be ake Catechism valve and the independent brake valve, what would be the effect? A. When an independent brake application was made and the handle of the independent brake valve was lapped, this leak would permit the brakes to gradually release; in the automatic application it would make no difference, but when a release of an automatic application of the train brake was made it would gradually destroy the holding feature of the automatic brake valve. Q. If there should be a leak through the rotary of the independent brake valve, what would be the effect? A. While both brakes are released and both brake valves are in running position, it will cause a slight blow at the emergency exhaust port of the automatic brake valve. When either the automatic or the independent brake is applied in partial service, it will cause a building up of pressure in the application cylinder to the maximum adjustment of the pres- sure reducing valve, and hence cause the brakes to apply with full independent pressure. It will also cause a building up of pressure in the application cylinder, while the" handle of the automatic brake valve is in release or in holding positions. Q. If the main-reservoir connection to the distributing valve should leak, what would be the effect? A. It would make no difference with the operation of the distributing valve, but it would make the pump work harder to supply the leak. Q. If the application valve 5 should leak, what would be the effect, and how could the leak be detected? A. It would increase brake-cylinder pressure above that in the application cylinder, and force the application piston and application valve back far enough to allow the surplus air to escape at the brake-cylinder exhaust port. The leaky ET Locomotive Brake Equipment 257 valve would be detected by the escape of brake-cylinder air at the exhaust port during a brake application. Q. Would this be true if there were leakage in the brake cylinders at the same time? A. That would depend on whether the leakage from the brake cylinders was greater or less than that through the application valve. If greater, there would be no escape of air at the brake-cylinder exhaust port; if less, there would be. Q. If the application-piston graduating spring 20 (Fig. 81) should break, what would be the effect? A. The application piston and valve would be less sensi- tive in graduating. Q. If the exhaust valve 16 should leak how could it be known? A. By a blow from the brake-cylinder exhaust port while the brakes are applied. Q. How would a leaky packing leather and packing ring in the application piston affect the operation of the distributing valve in brake applications? A. It would tend to reduce the efficiency of the valve in maintaining any cylinder leakage. Q. If equalizing slide valve 31 should leak, what effect would it produce? A. When brakes are released and both brake valves are in running position, there would be a slight blow at the emer- gency exhaust port of the automatic brake valve. If the in- dependent brake were applied there would be an increase in application-chamber pressure which would cause the brakes to go on harder. If the automatic brake is applied in partial service, then application-cylinder pressure would increase and the brakes go on harder to the limit of full equalization, if ordinary pressure is used; or if high-speed pressure is used, 258 Air-Brake Catechism until the safety valve would open and relieve the application- cylinder. Q. Suppose the engine having the leaky equalizing slide valve were second in a double-header, what might happen then? A. The brakes might entirely release, if the application were a partial service. Q. Suppose the graduating valve 28 should leak, what would be the effect? A. In release position no effect would be observed. In partial service application, the effect would be practically the same as stated would occur with a leaky slide valve 31. PRINCIPAL DIFFERENCES BETWEEN THE No. 5 AND No. 6 ET EQUIPMENTS. Piping. In the No. 5 Equipment, the double-heading cock is a double cut-out cock, one passage for the brake-pipe, and the other for the double-heading pipe, the latter taking the place of the distributing-valve release pipe in the No. 6 equip- ment. The double-heading pipe does not connect with the Independent Brake Valve. The plug in the double cut-out cock is arranged so that when the brake-pipe passage is open, the double-heading-pipe passage is closed, and vice versa, Consequently the double-heading pipe is only used when the engine is second in double heading, or a helper. The dead-engine by-pass connection was not furnished with the No. 5 equipment unless specially ordered, so that in many cases it will not be found in that equipment. A single-pointer air gage was furnished with the No. 5 equipment in place of the No. 2 duplex gage, its connection being to the brake-cylinder pipe only. Manipulation. The only difference in manipulation be- tween the two equipments is in double heading; with the ^ ET Locomotive Brake Equipment 259 No. 5 equipment, the double cut-out cock is turned to close the brake-pipe, and the handle of the automatic brake valve placed on lap on all engines except the one from which the brakes are being operated. In all cases of application and release of the brakes, the manipulation is exactly the same. Auiomatic Brake Valve. The H-5 automatic brake-valve used with the No. 5 equipment differs from the H-6 Valve in the arrangement of ports in rotary valve and seat; in an emergency application, the equilizing reservoir is connected with the application chamber of the distributing valve, there- by increasing the volume of the latter and it's pressure of equalization with the pressure chamber to obtain the in- creased emergency brake-cylinder pressure; but the increase obtained by this arrangement is only about 20 per cent, in- stead of 30 per cent, as obtained with the No. 6 equipment. In the H-5 brake-valve, main-reservoir pressure does not feed into the application cylinder of the distributing valve; in the No. 5 equipment, this feeding occurs in the distribu- ting valve itself. In the H-5 brake-valve, the warning port blows main-reser- voir air to the atmosphere instead of feed-valve-pipe air. Also when the handle is on lap, the double-heading pipe connection is connected to the atmosphere. Independent Brake Valve. The SF Independent Brake Valve, used with the No. 5 equipment, has only three pipe connections, and is quite different in arrangement of ports and details from the S-6 valve just described. Its manipula- tion, however, is just the same. Distributing Valve. The No. 5 distributing valve differs from the No. 6 in many ways. The application cylinder and application chamber are always directly connected, without regard to the position of the equalizing slide valve; a port connects main-reservoir pressure with the equalizing slide- valve seat, which, in emergency applications, feeds main-res- 260 Air-Beake Catechism ervoir air into the application chamber; the safety valve is set for 53 pounds, instead of 68; port m, (Fig. 86) does not exist, there being no provision in the No. 5 distributing valve for the application of the quick-action cylinder cap; connections II and IV, (Fig. 86) are reversed in the No. 5 distributing valve; the main-reservoir and brake-pipe con- nections are for smaller sized pipe ; the arrangement of ports in equalizing slide valve and seat are different; the supply valve is of slightly different construction ; there is no gradua- ting sleeve and spring in the equalizing piston ; there is no drain cock (No. 38, Fig. 86) , a small pipe plug being used in- stead; the arrangement of ports in the end of the double- chamber reservoir are different, so that a No. 6 distributing valve cannot be used on a No. 5 reservoir, and vice versa. But it responds to brake-pipe reductions in quite the same manner, so that, outside of the higher emergency brake-cylin- der pressure with the later equipment, an engineer could not tell from the cab which distributing valve was installed. All other parts of the two equipments are practically the same. CHAPTER VIII. AIB-SIGNAL SYSTEM. The signal equipment described in this chapter refers to the engine equipment used with the old-style Westinghouse ap- paratus. The arrangement on the cars has not been changed, while that in the new schedule ET Westinghouse equipment has been modified slightly. This modification is explained more in detail in the chapter covering the ET equipment. Q, What form of signal was used before the com- pressed-air signaling apparatus was invented? A. The old bell rope and gong signal, such as is now used on freight trains. Q. Do all roads use the air signal in passenger service? A. Not all, but most roads do. Q. What parts of the signaling apparatus are found on the engine? A. The strainer, the reducing valve (Fig. 99), the whis- tle valve (Fig. 98), the whistle (Fig. 100), and the pipe connections as shown in Fig. 94. Q. What parts are found on the car? A. The discharge valve (Fig. 97), the signal cord run- ning the length of the car, and the signal-pipe connections as shown in Fig. 95. Q. Where is the discharge valve (Fig. 97) usually located? A. As shown in Fig. 95, although it is sometimes found inside the car over the door. 262 Air-Brake Catechism Q. Why is it better placed outside? A. When it is so placed the noise of the discharge will not affect nervous people. Q. How does the car discharge valve work? A. The signal cord is attached to the valve in the hole of 5 (Fig. 97) ; when the cord is pulled, valve 3 is forced from its seat, allowing signal-pipe pressure to escape to the atmosphere. ItD AS THE CONSTRUCTION Of THE ENGINE DEMANDS. Fig. 94. — Signal Equipment for Engine Not Equipped with Schedule E. T. Q. What is the trouble when there is a constant leak from the discharge valve? A. There is dirt on the seat of valve 3 (Fig. 97). Q. Where is the signal valve (Fig. 98) located? A. In the cab, where it will not be subjected to severe heat or cold. Q. Where are the reducing valves (Fig. 99) usually- placed? Air Signal System 263 A. It was formerly customary to locate them outside, next to the main reservoir, but now good practice locates them inside the cab where they cannot freeze in winter. Q. What is the duty of these valves? A. To maintain a constant pressure in the whistle line. Q. Explain the action of the reducing valve (Fig. 99). A. Spring 13 controls the movement of piston 10 which, Fig. 95. — Location of Signal Apparatus on Coach. in turn, forces check-valve 4 from its seat when the tension of the spring 10 is more powerful than the pressure down- ward on the piston. The tension of this spring is usually adjusted to with- stand a pressure of 40 pounds acting downward on the piston, hence when the pressure is less than this amount the spring will raise the piston upward to the position shown in Fig. 99. In this position air entering from the main reservoir 264 Air-Brake Catechism connection at A will pass through the restricted opening shown, past the unseated check valve 4 and on, as indicated by the arrows, and out to the signal pipe at B. As soon as the pressure in chamber C and the signal pipe is greater than' the tension of spring 13, the piston will be forced down- ward, allowing the main-reservoir pressure and the spring 6 to force the check to its seat. This valve will not open again until by leakage or otherwise the pressure in the signal pipe has been reduced below 40 pounds. Q. Of what use is the plug valve in the upper left-hand corner? A. To cut out main-reservoir pressure in case we wish to take the reducer apart. Fig. 96. — Air Strainer on Engine. Q. What is the object of the air strainer (Fig. 96). A. To keep any foreign matter from entering the re- ducing valve or signal system, where it may occasion an im- proper response of the signals. Q. Of what does this strainer consist? A. Of the body 8 (Fig. 96), perforated brass discs 3, and the space between these perforated plates is filled with curled hair. Q. Has this strainer ever been used to fulfill an office other than as described above? Air Signal System 265 A. Yes; a tee is sometimes inserted between the strainer and the reducing valve. A branch of the tee is then piped to the pnmp governor, and the strainer performs the double duty of keeping foreign matter both from the signal system and the pump governor. Q. Is any material other than curled hair ever used to fill in the space between the perforated plates 3 (Fig-. 96)? A. Yes; sponge has been used for this purpose, but the results obtained were not satisfactory. The hair seems to Fig. 97. — Car Dischaege Vaxve. collect the dirt better and it is much easier to clean than the sponge, as it permits of a freer separation. Q. Where is the whistle (Fig. 100) located? A. In the cab, as near the engineer as convenient. Q. To what is it connected? A. To a pipe which leads from the signal valve as in- dicated (Fig. 98). Q. What is its use? A. As the signal or whistle valve (Fig. 98) operates, the 266 Air-Brake Catechism air leaving this valve escapes through the whistle (Fig. 100). The blast signals the engineer. Q. Where does the air come from that supplies the signal system? A. From the main reservoir on the engine. Q. Explain the passage of the air from the main reservoir through the signal system. x ^ to whistle Fig. 98. — "Westinghouse Signal Valve. A. It first passes from the main reservoir (Fig. 94) through the strainer and reducing valve. After leaving the reducing valve there is a tee in the pipe, one branch of which leads to the signal valve (Fig. 98), and the other back into the train. Under each car (Fig. 95) there is a strainer in a tee, and a branch of the whistle line goes to the discharge valve (Fig. 97). Air Signal System 267 Q. Explain the operation of the Westinghouse signal valve (Fig. 98) in charging. A. After the air passes from the main reservoir and through the reducing valve, it is free to go back into the train and also enter the signal valve at Y. It then passes through the contracted port d into cavity A on top of the rubber dia- Fig. 99. — Westinghouse Signal Reducing Valve. phragm 12, and around through port c. The lower half of the stem 10 is three sided, so that the air can pass up to where the stem looks to be tight in the bushing 9. This joint is not tight, but sufficiently so to allow the air to feed by into cham- ber B very slowly. The reducing valve is adjusted to forty pounds, and if we wait a short time the forty pounds will equalize on both sides of the diaphragm 12; that is, there 268 Air-Brake Catechism will be forty pounds in each chamber A and B, as there is also throughout the signal pipe on the train. Q. What does the conductor do if he wishes to signal the engineer? A. He pulls the signal cord in the car. Q. What is effected by this? A. It makes a sudden reduction of signal-pipe pressure through the car discharge valve- (Fig. 97). Q. What is the effect on the Westinghouse valve (Fig. 98). A. This starts a reduction wave throughout the signal Pig. 100. — Signal Whistle. pipe, and in the signal valve it is first felt in chamber A, on top of diaphragm 12 (Fig. 98). The pressure in cham- ber B, being unable to equalize quickly with that in cham- ber A, on account of the snug fit of the stem 10 in bushing 9, is now greater than the pressure in chamber A. The dia- phragm 12 and the stem 10 attached to it are lifted, uncover- ing the port in the bushing 7. The stem is lifted sufficiently to allow air from chamber B and the air coming through port c to pass out at e and through the pipe to the whistle (Fig. 100), causing a blast as long as the stem 10 is off its seat. Air Signal System 269 The same wave reduction that started the signal valve into operation also opened the reducing valve (Fig. 99) to allow main-reservoir pressure to supply the whistle line. A wave of increased pressure now takes the place of the reduction wave, and air passing into chamber A of the signal valve forces the diaphragm 12 down, causing the whistle to cease blowing. Q. How long" must we wait before again trying to put the signal valve in operation? A. Until the pressures have had time to equalize in cham- bers A and B (Fig. 98). Q. How many seconds should we wait? A. Usually two at least, and three is better. Q. Give a rule by which we can pull the whistle signal cord m the car and gain the best results. A. When pulling the cord, make an exhaust of one second, and then wait three seconds to allow the whistle to cease blowing and the pressures to equalize throughout the signal system before making another reduction. Q. In pulling the signal cord, what should always b© borne in mind? A. That it is not the amount of reduction but the sud- £ denness that causes the whistle to blow. Peculiarities and Troubles of the Signal System. Q. If no air gets into the signal pipe when an engine is coupled to a train, and we know that the cocks in the signal pipe stand properly and the hose are in order, what should we look at first? A. The plug cock in the reducing valve (Fig. 99) ; or, if 270 Air-Brake Catechism the weather is cold and the reducer is outside, it may be frozen. Q. What else might cause this trouble with the reducer (Fig. 99)? A. It may be that the small taper port in the reducer (Fig. 99), where the main-reservoir pressure enters, is plugged shut or the strainer may be blocked. Q. What will close this port? A. Oil from the air end of the pump and the corrosion from the inside of the pipes. The small ports in the reduc- ing valve are also sometimes closed from this cause. Q. What is the trouble if the signal cord is pulled in the car and no air issues from the car discharge valve? A. The cut-out cock (Fig. 95) in the saloon has very likely been closed. Q. Give conditions that would result in the air whistle not responding. A. A dirty strainer in the tee under the car where the branch pipe to the car discharge valve couples to the main signal pipe; the strainer in the car discharge valve, as used in the old equipment, being dirty; port d (Fig. 98) being stopped up; a too loose fit of stem 10 (Fig. 98) in bushing 9; a baggy diaphragm (Fig. 98), or a hole in it; the bowl of the whistle (Fig. 100) being closed with scouring material, or the bell of the whistle being improperly adjusted; a re- duction that took enough air from the signal-pipe but did not take it fast enough, or, as explained before, the reducer might be frozen. Q. Why would the whistle not respond if port d (Fig. 98) were closed? A. No air could reach the whistle. Q. Why, with a loose fit to stem 10 (Fig. 98) in bush- ing 9, would the whistle not respond? Air Signal System 271 A. If the reduction were not made sufficiently quick with the car discharge valve, especially on a long train, the fric- tion of the air passing through the pipe would tend to de- crease the suddenness of the reduction, so that, when the wave reached the signal valve, the reduction might be so weak that, if stem 10 were a loose fit in bushing 9, the air in chambers A and B might equalize without raising dia- phragm 12 (Fig. 98). Q. Why would a baggy or stretched diaphragm (Fig. 98) cause the whistle not to respond? A. When the reduction is made in the signal pipe, a re- duction is made in chamber A of the signal valve, leaving the pressure in chamber B greater. If the diaphragm is bagged, the pressure in chamber B lifts the diaphragm, but the stem is not moved. Q. What causes this diaphragm to bag? A. The use of poor rubber, or oil from the pump work- ing through on the rubber, causing it to decay. A diaphragm is occasionally found with a hole rotted through it, allowing chambers A and B to be directly connected. Q. What may cause a whistle to respond only once when the conductor pulls the cord twice? A. He may have pulled the cord the second time before the whistle stopped blowing the first, thus getting one long blow, or he may have made the second discharge before the pressures in chambers A and B had become equalized. Q. What will happen if dirt gets on the seat of valve 4 (Fig. 99)? A. The valves cannot close, and we will get main-reser- voir pressure in the signal-pipe. Q. What effect has this? A. The whistle is likely to blow, especially on a short train, when the brakes are released; the air whistle on the engine 272 Air-Brake Catechism will screech when used; and the whistle may blow two or three times for one reduction at the car discharge valve; there will be a stronger exhaust from the car discharge valve than usual, and hose are more likely to burst. Q. Why is the whistle likely to blow when the brakes are released, if there is main-reservoir pressure on the whistle line? A. Because to release brakes the main-reservoir pres- sure is thrown into the brake-pipe. This makes the pres- sure in the main reservoir less than that in the signal pipe, and, on account of the dirt on the seat of the valve (Fig. 99), the signal-pipe pressure feeds back into the main reservoir, and the reduction thus made in the signal pipe causes the air whistle to blow. Q. Why, with this trouble, is the whistle more likely to sound on an engine alone than with a train, when the brakes are released? A. With an engine alone there is but a small volume of air on the signal line, and the signal-pipe pressure feed- ing back into the main reservoir would cause a more sudden reduction than if the signal pipe were longer and the vol- ume greater, as on a train. Q. Why will the air whistle on the engine screech when used? A. Because the bell is adjusted to be used with only a forty-pound pressure instead of ninety or more. Q. Why is the whistle likely to blow two or three times with one reduction from the car discharge valve, if main-reservoir pressure is in the signal pipe and the stem 10 is loose in bushing 9 (Fig. 98) of the signal valve? A. Because a reduction at the car discharge valve starts the signal valve in operation, and the reducer cannot feed air into the signal pipe properly to cause the signal valve Air Signal System 273 to close until the signal-pipe pressure is below forty pounds. The tendency for the pressure to fluctuate in chambers A and B, due to the loose fit of the stem 10, causes the dia- phragm to bounce and the whistle to respond two or three times. Q. If an engineer wishes to know how much pressure he has in his signal pipe, and he has no gage with which to test it, how can he determine it? A. Shut off the pump and open the bleed cock on the main reservoir, then get up in the cab and watch the red hand. When the whistle blows, the red hand represents a trifle less pressure than is being carried in the signal pipe. Q. Why does the whistle blow? A. Because, when the main-reservoir pressure is drained below the pressure in the signal pipe, the pressure feeds from the signal pipe back into the main reservoir, causing a re- duction of the signal-pipe pressure, and this usually causes the whistle to blow. Q. What is likely to make a whistle give one long blast? A. A tight fit in bushing 9 of stem 10 (Fig. 98). Q. What will cause a whistle to sing constantly? A. Dirt on the seat of stem 10 in bushing 7 (Fig. 98). Q. Why may jars cause a whistle to blow? A. Oil baking upon the diaphragm of the signal valve makes it rigid, and a jar will sometimes shake the stem from its seat. Q. What would we do with the reducer (Fig 99) to increase or decrease the pressure in the signal pipe? A. Screw up on the bottom nut to increase it, and down to decrease it. CHAPTEE IX. BRAKING POWER AND LEVERAGE Q. What is meant by braking power? A. The force applied by the shoes against the wheels to stop the motion of a car. Q. What is meant by the percentage braking* power? A. The total brake-shoe pressure as compared to the light weight of the car. The percentage is found by dividing the total braking power by the light weight of a car. Q. How is the braking power determined? A. By assuming a definite air pressure in the brake cyl- inder, and computing the total force developed against the wheels by the shoes due to this pressure acting against the brake cylinder piston. Formerly the maximum air pressure that could be obtained in the cylinder, was used as a basis of calculation ; but since, with 70 pounds in the brake-pipe, a plain triple valve obtains 50 pounds maximum cylinder pres- sure, a quick-action triple valve 60 pounds pressure, the ET equipment 65 pounds pressure, etc., it is now the custom to use 50 pounds cylinder pressure uniformly as a basis of calculation of braking power in all classes of equipment. All percentages given below are based on a 50-pound cylinder pressure. Q. What per cent of the light weight is used as brak- ing power on a freight car using 50 pounds cylinder-pres- sure as a basis of calculation? A. Sixty per cent or six-tenths of the light weight ©f the car. Braking Power and Leverage 275 Q. On a passenger car? A. Eighty per cent or eight-tenths of the light weight of the car, excepting with the new high-speed brake (type L triple valve and supplementary reservoir), when ninety per cent is used. Q. Can these percentages be used if the car has two six-wheel trucks, and only two pairs of wheels on each truck are braked? A. No; the percentages given refer to a certain per cent of the total weight on the rails of the braked wheels. If only two pairs of wheels are braked on each truck, and the car rests equally on all six pairs of wheels, it is clear that the weight of the car that is supported by the braked wheels is only four- sixths of the total weight of the car. Therefore in such a case, eighty per cent (or ninety) of four-sixths (or two- thirds), of the total light weight of the car should be used as the braking power. Or, which is the same thing, use 2/3 of the percentages; 53 1/3 per cent (or 60 per cent) of the to- tal light weight. Q. What per cent braking power is used in designing driver brakes? A. With the old standard equipments, seventy-five per cent or three-fourths of the weight on the drivers when the engine is ready for the road. With the No. 6 ET equipment, sixty per cent of the same weight is used. Q. What per cent braking power is used on engine truck or trailer-wheel brakes? A. With the old standard equipment sixty per cent; with the No. 6 ET equipment, forty-five per cent — of the weight of the engine in working order on them, in each case. Q. What per cent braking power is used on tenders? A. With old standard passenger tenders, or freight ten- ders equipped with quick-action triple valves, 85 per cent 276 Air-Brake Catechism of the light weight; with old standard freight tenders hav- ing plain triple valves, 100 per cent is nsed; with tenders equipped with No. 6 ET Equipment, 80 per cent is used. Q. Why is a larger per cent braking power used on tenders than on engines or freight cars? A. Because tenders are practically always loaded. Q. How were these percentages determined on as safe? A. By actual tests in the different kinds of service. Q. What brake-cylinder pressure is used in figuring the braking power with the different sizes of cylinders? A. Fifty pounds. Q. How do we calculate the force acting on the push rod due to the pressure in the cylinder acting on the piston? A. Multiply the diameter of the piston by itself; the product by the decimal .7854, and this last product by the air pressure in the brake cylinder. Q. What force would act on the push rod of an 8-inch cylinder? A. 8 X 8 X .7854 X 50 = 2513, usually figured as 2500 pounds. Q. Explain the difference in the percentage braking power of a freight car light, and the same car when loaded to its full capacity. A. Sixty per cent of the light weight of a freight car is considered safe braking power. If the light weight of a freight car is 40,000 pounds, it is given 24,000 pounds braking power. If the capacity of the car is 100,000 pounds, when loaded to its full capacity the total weight of the car and contents is 40,000 + 100,000, or 140,000 pounds, but we have only the brake-shoe pressure to stop the car loaded that is used when it is light. In full service application we obtain fifty pounds pressure Braking Power and Leverage 277 in the brake cylinder. This gives sixty per cent braking power when the car is light, but when the car is loaded, the per- centage of braking power to the total weight of the car and contents is only seventeen per cent. In emergency, we get about sixty pounds pressure in the brake cylinder which amounts to seventy-two per cent braking power with a light car; but with the car loaded, when the brakes are set in emergency, the braking power is about twen- ty and one-half per cent of the total weight of this car. Q. How is the percentage braking power of a pas- senger car affected by its load? A. Not very much, because eighty per cent of the light weight of the car is used as braking power, and when loaded, the additional weight is seldom as much as 10,000 pounds. LEVER OF 1st KIND Fig. 101. Q. What forces are usually figured as acting at the push rod with the different sized cylinders, the cylinder pressure being figured at fifty pounds in service and sixty in emergency with the quick-action triple, and fifty pounds with the plain triple in either service or emergency? A. Service application: 6 in. 8 in. 10 in. 12 in. 14 in. • 16 in. 18 in. 1400 2500 4000 5600 7700 10,000 12,200 Emergency application : 1700 3000 4700 6800 9200 12,000 14,700 By using the following cuts and formulae, the braking power on a car with any kind of leverage may be figured. 278 Air-Brake Catechism There are three classes of levers: I. When the fulcrum c (Figs. 101 and 102) is between the force F and the weight W. II. When the weight W (Figs. 103 and 104) is between the force F and the fulcrum c. III. When the force F (Figs. 105 and 106) is between the weight W and the fulcrum c. Figs. 101 and 102 represent a lever of the first class. Q. What brake-shoe pressure W will result with a force F = 2500 pounds, b = 16 inches, a = 8 inches? F X h 2500 X 16 A. W = or W = 5 or W = 5000 a 8 pounds. The forces W and F act in the same direction on the levers, and the force at c acts on the lever in an opposite direction from both and must be equal to their sum, or 7500 pounds. Q. What is the distance a if F = 2500, b = 16 inches, and W = 5000? FX b 250 ) X 16 A. a = — 77F — ; substituting values, 5000 or a = 8 inches. Q. What is the force F, when W = 5000, a = 8 inches, and b = 16 inches? W X a A. F = — =- ; substituting values, 5000 X 8 F = Tg or F = 2500 pounds. Q. How do we find b if W = 5000 pounds, F — 2500 pounds, and a = 8 inches? Braking Power and Leverage 279 A. b W Xa F substituting values, 16 inches. 5000 X 8 Figs. 103 and 104 represent levers of the second class witl the weight between the fulcrum c and the force F. FORMULA W— F= a Wxa Fxb W Wxj Fig. 102. — Levee of 1st Kind. Assume that F == 2500 pounds, a = 8 inches, d — 16 inches, and b = a -J- ^ or 24 inches. Q. What is W? F X b A. W = ; substituting values, 2500 X 24 W = 5 or W = 7500 pounds. In this class of levers we see that the forces F and W act in opposite directions on the lever, and the force exerted at c will be equal to the difference between F and W, or 5000 pounds. We may compute values for a, F or b, as was illustrated in 280 Air-Brake Catechism the first class of levers, if we know the values of the other three. Figs. 105 and 106 represent the third class of lever with the force F exerted between the weight W and the fulcrum c. Assume that F = 2500 pounds, b = 8 inches, d ■ == 16 inches, a = b + d, or 24. Q. What is W? F X b A. W = ; substituting values, 2500 X 8 F = g7 or Tf = 833 1/3 pounds. ler LEVER OF 2nd KIND Fig. 103. W and F act in opposite directions on the lever in this case, and the force exerted at the fulcrum c will be equal to the difference between F and W, or,' in this case, 1666 2/3 pounds. The other three formulae 1 may be used to find the value of a, F or b when the other three values are known, as already shown. Besides speaking of levers as first, second, and third class, they are known by their proportions as 1 to 1, 2 to 1, 2% to 1, etc., according to the amount the force F is raised or di- Braking Power and Leverage 281 minished, due to the class and proportions of the levers em- ployed. To find the proportion of a lever of the first class, divide the distance of the fulcrum c to the force F by the distance FORMULAE. yy _F X b A_F_X_k Wxa F= Fig. 104. — Levee of 2jn t d Kind. W Wxa d— b LEVER OF3rd KIND Fig. 105. W= FORMULA Fx b a= Fxb F -Wxa b W Wxa Fig, 106. — Lever of 3rd Kind. 282 Air-Brake Catechism from the fulcrum c to the weight Wj or, referring to Fig. 101, it would be: b -i- a or 16 -f- 8 = 2. This proportion of lever would be called a 2 to 1 lever. The force F is multiplied by 2 at W. In the second class, or Fig. 103, the proportion of the lever would be represented by : b -=- a or 24 -f- 8 = 3, or a 3 to 1 lever. In the third class, or Fig. 105, the proportion of the lever would be represented by: b -f- a or 8 -j- 24 == 1/3. or a 1/3 to 1 lever, in which case the proportion and class of levers reduces the force 3 to 1 instead of increasing it. Having studied the classes of levers, we will now make a practical application of their use in figuring the proportion of the levers to be applied to a car of given weight. We wish to design a brake for a passenger car, the weight of which is 60,000 pounds, and use the Hodge system of levers as shown in Fig. 107. Eighty per cent, or eight-tenths of 60,000 pounds is 48,000 pounds. 48,000 pounds will be the braking power to apply to the wheels of a passenger car weighing 60,000 pounds. 48,000 -=- 4 = 12,000, or the amount of braking power to be developed at each brake beam. The length of the truck levers has to be determined from the truck construction. We will suppose the dimensions to be — long end, 28 inches; short end, 7 inches. The truck levers are of the second class and substituting the values in the formula (Fig. 104). W X a 12,000 X 7 F = — 7 or F = — or F = 2400 u 3d That is, to get a power W of 12,000 pounds against the brake beam, a force of 2,400 pounds is necessary at the top of the live truck lever. Braking Power and Leverage 283 The forces F and W act on the live lever in opposite direc- tions, so the force acting at fulcrum c will he 12,000 — 2400 = 9,600. This power is transmitted to the bottom of the dead lever, which is of the same class as the live lever; but the force F is applied at the bottom instead of the top of the lever. We have from Fig. 104 : W FXb or W 9,600 X 30 24 or W = 12,000 So that, with a force of 2,400 pounds acting at the top 28" \ d • of the live lever of the dimensions given, a power W of 12,000 pounds is developed at each truck brake beam. The dead truck lever need not be of the same length as the live lever, but the proportions between the holes must be the same in each. The force of 2,400 pounds that acts on the top of the live lever also acts at X, the end of the floating lever, and we must now determine what force must act on the rod that con- nects the end of the cylinder lever with the floating lever. This rod is connected at the middle of the floating lever, 284 Air-Brake Catechism and the power at this point must be sufficient to develop a force of 2,400 pounds at each end of the floating lever. The force exerted at the middle must be 2 X 2,400 or 4,800 pounds, as half of this amount is given to each end of the floating lever. This 4,800 pounds acting at the center of the floating lever must also act at the end of the cylinder lever, being connected directly with it. What we now wish to determine is, with any desired length over all, how must the holes be spaced in the cylinder lever that the pressure acting on the push rod will produce a force of 4,800 pounds at the outer end of the cylinder lever. With any brake equipment except the new high-speed brake,, a 12-inch cylinder is recommended by the Westinghouse Company to be used with this weight of car. With a 50-pound cylinder pressure, the 12-inch c}dinder gives a push at the piston rod of 5,600 pounds. We will suppose the distance between the outside holes of the cylinder lever to be 30 inches. The following rule will enable us to locate the middle hole in the cylinder lever to which the tie rod is attached. Multiply the force acting at the piston by the length of the lever between the outside holes, and divide the product by the sum of the forces acting at both ends of the cylinder lever. The result will be the distance from the middle hole of the cylinder lever to the hole to which the connection running to the floating lever is attached. Applying this rule to our problem we have 5,600 X 30 = 168,000 5,600 + 4,830 = 10,400 168,000 -f- 10,400 = 16.15 30 — 16.15 =13.85 The distance between the holes at the short end is 13.85 and the long end 16.15 inches, and, according to the rule, the Braking Power and Leverage 285 long end is connected to the connection running to the float- ing lever. The force exerted at the middle hole of the cylinder lever is also communicated to a hole similarly placed in the other cylinder lever, so, that, using the same levers, we will obtain the same braking power on the wheels of the other truck. In figuring the levers for the Stevens system of leverage, the power desired at the top of the live lever is figured the same as just explained. When we know this force, we know that the same power has to exist at the outer end of the cylinder lever, as the Stevens system has no floating lever. This we figure by the rule already given for spacing the holes in the cylinder levers. To figure the braking power of a car already equipped, we start with the force acting on the piston rod and work to- wards the truck levers by the aid of the formulae given. To use the formulae, first determine the class of lever with which we have to deal. The foregoing illustrations were practical applications of the formulae, in calculating the proportion of levers that would give a proper braking power on a car of known weight. We will now consider a shorter method of calculating the proportion of levers for a Hodge and for the Stevens systems of leverage for this same car. Fig. 107 (page 283) shows the Hodge system of levers. If this were a Stevens system, the floating lever would not be used, and the other end of the connection to the live lever of the truck would connect directly with the outer end of the cylinder lever. With the Stevens system the hand-brake connection runs from the brake mast direct to the top of the dead lever. (1.) To find the total braking power required: For any equipment except the new high-speed brake, sub- 286 Air-Brake Catechism tract 20 per cent, of the weight of the car on the wheels to be braked for passenger cars, and 40 per cent, for freight cars. For passenger cars with the new high-speed brake, subtract 10 per cent. (2.) To find the total leverage required: Divide the total braking power required by the total pres- sure on the piston, 50-pound cylinder pressure taken as a basis of calculation. The total leverage should usually not exceed 9 to 1. (3.) To find the proportion of the brake-beam levers: Divide the entire length of the lever by the short end, if the truck has a better:. ?~nnection; if it has a middle con- nection, divide the long by the short end. (4.) To find the total brake-beam leverage: Multiply the proportion of the brake-beam levers by two, for the Hodge system, and by four for the Stevens system. (5.) To find the proportion of the cylinder lever: Multiply the whole length of the lever by the required total leverage and divide the product by the sum of the total brake-beam leverage plus the required total leverage. If the required total leverage is greater than the total brake-beam leverage, the long end of the lever must go next to the cylinder ; if less, the short end goes next to the cylinder. The dead and live truck levers may be of different lengths, but must be of the same proportion to develop the same braking power. EXAMPLE. Hodge system of levers, as shown on page 283, also the lengths of the truck levers. Weight of car, 60,000 lbs. Old-style standard brake equip- ment used. A 12-inch cylinder is used with this weight of car. A pressure of 5,600 lbs. is developed on a 12-inch piston, using 50 -pound cylinder pressure as a basis. Braking Power and Leverage 287 57, total leverage required. (1.) 60,003 lbs. less 20 per cent, is 48,030 lbs (2.) 48,000 lbs. -t- 5,600 = (3.) 35-^-7 = 5, brake-beam leverage. (4.) 5X2= 10, the total brake-beam leverage. Assume the length of the outside holes of the cylinder lever to be 30 inches. (5.) (30 X 8.57) ~ (8.57 + 10) = 13.85 inches. 33 — 13.85 = 16.15 inches. STEVENS SYSTEM OF CAR BRAKE LEVERS Fig. 108. HODGE SYSTEM OF CAR BRAKE LEVERS Pig. 109. TENDER BRAKE LEVERS Pig. 110. 288 Air-Brake Catechism The required leverage is less than the total brake-beam leverage, hence the short end of the cylinder lever connects to the jjiston. Stevens system — same car. (1.) 60,000 lbs. less 20 per cent, is 48,000 lbs. (2.) 48,000 -r- 5,600 = 8.57, total leverage required. (3.) 35-^7 = 5, the brake-beam leverage. (4.) 5 X 4 = 20, the total brake-beam leverage. The cylinder lever is 30 inches between outside holes. (5.) (30 X 8.57) -f- (20 + 8.57) = 9 inches. 30 — 9 = 21 inches. The required leverage is less than the total brake-beam leverage, hence, according to the rule, the short end of the cylinder lever (9 inches) connects to the piston. Q. Give a rule by which the braking power on prac- tically any engine, tender or car can be calculated. A. Multiply the force acting by the distance from the force to the fulcrum, and divide this product by the distance from the work to the fulcrum; the result will be the work that can be accomplished. In this rule let F = force, W = work, a = distance from the point at which the force is applied to the fulcrum, h = distance from the fulcrum to the point at which the work is to be . accomplished. Then we have the following formula which can be used : F X a Q. What must be determined to use this rule intelli- gently? A. It must always first be determined which point on any Braking Power and Leverage 289 lever is the fulcrum. For instance, in considering the piston lever (Fig. 107) the fulcrum is the rod which connects the piston and cylinder levers when we wish to ascertain the amount of work that can be done at the outer end of the piston lever. If we wish to ascertain the amount of work that can be done on the rod connecting the piston and cylinder levers, the fulcrum would then be the outer pin in the pis- ton lever. To find the work accomplished on the brake shoes connected to the live truck levers (Fig. 107), the lower pin of the live lever is the fulcrum; but if we wish to know what work is done on the bottom truck connection by a force acting on the |S^_ /£\ f^ k 1/ h i [o\ ^> EL U Fig. 111. — American Equalized Brake. top of the live lever, the point at which the brake shoe is shown represents the fulcrum. What has been said on the subject of brake leverage in this chapter is all useful, and a thorough understanding of it will enable one to make many short cuts in leverage problems presented for consideration, but the last very simple rule will be found to be sufficient with which to calculate the braking power in practically any system of leverage. 290 Air-Brake Catechism Sizes of Cylinders to be Used on Cars and Tenders of the Following Maximum Light Weights, as Recommended by the Westing- house Air-Brake Company. passenger cars. Size of Cylinder. Standard Equipments, Including Old Style High-speed Brake. New Style High-speed Brake Equipments. 8" 16,000 to 28,000 16,000 to 25,000 10" 28,000 to 44,000 25,000 to 39,000 12" 44,000 to 63,000 39,000 to 56,000 14" 63,000 to 86,000 56,000 to 77,000 16" 86,000 to 113,000 77,000 to 100,000 18" 113,000 to 143,000 100,000 to 127,000 FREIGHT CARS. Size of Cylinder. Any Freight Equipment. 8" 22,000 to 37,000 10" 37,000 to 58,000 TENDERS. -Old Standard Equipment. Size of With Q,uick-action With Plain Cylinder. Triple Valve. Triple Valve. E T Equipment. 8" 15,000 to 26,000 15,000 to 22,000 15,000 to 28,000 10" 26,000 to 41,000 22,000 to 35,000 28,000 to 44,000 12" 41,000 to 59,000 35,000 to 50,000 44,000 to 63,000 14" 59,000 to 81,000 50,000 to 69,000 63,000 to 86,000 16" 81,000 to 106,000 69,000 to 90,000 86,000 to 113,000 American Brake Leverage. Q. How do you find the braking power on an engine equipped with the American equalized brake as shown in Fig. Ill, page 289? A. Multiply the cylinder value, or total push on the pis- ton, by the long lever arm, and divide this product by the Braking Power and Leverage 291 short lever arm. This result multiplied by 2 gives the total braking power. Q. With the long lever arm 25 inches long* and the short arm 5, what braking power would we have, using 12-inch cylinders? A. 56,000 pounds. Thus: 5,600 X 25 = 140,000 140,000-^ 5= 28,000 28,000 X 2 = 56,000 Q. If any different design of rigging were used than that shown in the sketch, how could the braking power be figured? A. First find the power exerted at the bottom of the rocker shaft and use this in connection with the cuts il- lustrating the different classes of levers. Q. What per cent of the total weight on drivers is used as braking power with driver brakes? A. Seventy-five per cent of the engine's weight on the drivers when ready for the road, when the old standard equipment is used, and sixty per cent when the ET equip- ment is used. Q. What braking power should be used on an engine whose weight on drivers is 90,666 pounds, using the old standard brake equipment? A. 90,666 X .75 = 68,000 pounds. Q. What weight should be on the drivers for an engine to have 68,000 pounds braking power, using the old stand- ard brake equipment? A. 68,000 -=- .75 == 90,666 pounds. Q. How should the holes be spaced in levers A and D on an engine having two pairs of drivers, to give an equal braking power on each wheel? 292 Air-Brake Catechism A. The middle hole in A should he equidistant from the two outside ones. The hole in the lever at D should be so as to have the connection attached at h stand about parallel with the track. The corresponding hole h at the other end of the lever D must be placed the same distance from the other end. Q. How should the holes be spaced in levers A, B and •D, if on a mogul or engine having three pairs of drivers? A. The distance e, lever A, should be one-half the dis- tance /. The distance g, lever B should be equal to h. The hole K, lever D, should be the same as on an engine having two pairs of drivers. Q. How should the holes in the levers A, B, C and D be spaced on a consolidation or engine with four pairs of drivers? A. The distance e in lever A should be one-third of f. The distance g, lever B, should be one-half of h. The dis- tance %, lever C, should be equal to j. The hole Jc in lever D should be the same as with an engine having two or three pairs of drivers. CAM BRAKE. The following simple rule to find the braking power de- veloped by a cam brake is given by Mr. H. A. Wahlert. Take two wires and place them between the brake shoe and the wheel; one at the top and one at the bottom of the shoe. Apply the brakes fully, and then measure the piston travel. Now release the brakes, recharge, remove the wires, and then apply fully again. Measure the piston travel again, and note how much more it has increased. Divide the addi- tional travel had upon removing the wires by the thickness of the wire, and multiply this by the value of the cylinder. The result is the braking power on each brake shoe. Air Hose 293 Four times this power is the total braking power developed on all four shoes. EXAMPLE. Thickness of wires, % inch. Piston travel, with wires inserted according to rule, 3 inches. Piston travel, with wires removed, 3y 2 inches. Value of 8-inch cylinder, 2,500 pounds. 3% inches — 3 inches = y 2 inch. y 2 inch -T- % inch = 4. 2,500 pounds X 4 = 10,000 pounds on each brake shoe. 10,000 pounds X 4 = 40,000 pounds on all four brake shoes. AIR HOSE. Q. What kinds of hose are used in the air brake and signal systems? A. Usually one-inch hose is used with signal equipment on cars in passenger, mail, and express service; while inch and three-eighths hose is used exclusively in freight service. Q. Is this a standard on all roads? A. ~No ; some roads use the inch and three-eighth hose with the brake equipment in both freight and passenger ser- vice. Q. Would there be any objection to using one-inch hose in freight service? A. The chief objection consists in the fact that the small hose presents a greater frictional resistance to the passage of air. This would be especially objectionable when it was desired to make a quick reduction to apply the brakes in quick action. Q. What is the object of having different hose couplings for the air and signal hose? 294 Air-Brake Catechism A. So that brakemen, when in a hurry, cannot couple the brake and signal hose together ; some companies paint the signal hose coupling red as a further aid when coupling hose. Q. How many cars of air are coupled up and operated? A. Some roads regularly couple as high as 115 cars and operate the brakes with the air supplied by a nine and one- half inch pump. Q. Could this be done with a poor hose? A. No, since with poor hose there is often considerable leakage not discernible with the naked eye. Q. How may porous hose be detected? A. By coating the outside with soapsuds. Q. What is the usual life of air hose? A. Passenger, about two and one-half years; freight, about two years. Q. How is air hose bought? A. Some on account of cheapness, some by a time guar- antee, and others by specification, the roads being willing to assume the risk in the latter case if they know the hose to be first-class when put in service. Q. What is the object of the markings shown on the hose (Fig. 112)? A. It is for the purpose of obtaining a record of the life of the hose. The one applying the hose should cut off the figure representing the month, in the line headed by the letter A, and the figure which shows the year. When the hose is removed the year and month should also be shown by cut- ting off the proper numbers. The following specifications have been recommended by the Master Car Builders' iissociation. They have been in force for some time on the railroads throughout the country, and constitute a definite standard for interchange. Aie Hose 295 AIR-BRAKE AND SIGNAL-HOSE SPECIFICATIONS ISSUED BT THE MASTER CAR BUILDER'S ASSOCIATION IN 1905. 1. All air-brake hose must be soft aud pliable, aDd Dot less than two-ply nor more than four-ply. They must be made of rubber and cotton fabric, each of the best of its kind made for the purpose. No rubber substitutes or short-fibre cotton to be used. NAME OF ROAD u> o» 03 04 05 06 07 12345 8 7 8 9 10 II 12 123458 7 8 9 10 1112 v» NAME OF MANUFACTURER a h m ■ o Pig. 112. — Standard Label for Air Hose. 2. The tube must be band-made, composed of three cal- endars of rubber. It must be free from holes and imper- fections, and in joining must be so firmly united to the cotton fabric that it can not be separated without breaking or split- ting the tube. The tube must be of such composition and so cured as to successfully meet the requirements of the stretching test given below; the tube to be not less than 3/32 inch thick at any point. 3. The canvas or woven fabric used as wrapping for the hose to be made of long-fibre cotton, loosely woven, and to be from 38 to 40 inches wide, and to weigh not less than 23 and 22 ounces per yard, respectively. The wrapping must be 296 Aie-Brake Catechism frictioned on both sides, and must have, in addition* a dis- tinct coating or layer of gum between each ply of wrapping. The canvas wrapping must be applied on the bias. Woven or braided covering should be so loose in texture that the rubber on either side will be firmly united. 4. The cover must be of the same quality of gum as the tube, and must not be less than 1/16 inch thick. 5. Hose is to be furnished in 22-inch lengths. Variations exceeding y± inch in length will not be permitted. Eubber caps not less than 1/16 inch nor more than % inch must be vulcanized on each end. 6. The inside diameter of hose must not be less than 1% inches nor more than 1 7/16 inches, nor must the outside dia- meter exceed 2% inches. Hose must be smooth and regular in size throughout its entire length, except at a point 2y 2 inches from either end, where the inside calendar of rubber may be increased 1/16 inch for the distance of y± inch toward either end and then tapering to regular diameter. 7. Each length of hose must have vulcanized to it a badge of white or red rubber as shown. On the top of the badge the name of the purchaser; on the bottom the maker's name; on the left-hand end the month and year of manufacture, and on the right-hand end the serial number and the let- ters "M. C. B. Std." These letters and figures must be clear and distinct, not less than 3/16 inch in height, and stand in relief not less than 1/32 inch, so that they can be removed by cutting without endangering the cover. Each lot of 200 or less must bear the manufacturer's serial number, com- mencing at (1) on the first of the year, and continuing consecutively until the end of the year. For each lot of 200, one extra hose must be furnished free of cost. 8. Test hose will be subject to the following tests: Air Hose 297 BURSTING TEST. The hose selected for test will have a section five (5) inches long cut from one end and the remaining seventeen (17) inches will then be subjected to a hydraulic pressure of 100 pounds per square inch, under which pressure it must not ex- pand more than 14 inch nor develop any small leaks or de- fects. The section will then be subjected to a hydraulic pres- sure of 400 pounds per square inch for ten minutes, without bursting. FRICTION TEST. A section one (1) inch long will be taken from the five (5) inch piece previously cut off, and the quality determined by suspend- ing a 20-pound weight to the separated end, the force being applied radially, and the time of unwinding must not exceed eight (8) inches in ten minutes. FlG> 113# STRETCHING TEST. Another section one (1) inch long will be cut from the balance of the five (5) inch piece, and the rubber tube or lin- ing will be separated from the ply and cut at the lap. Marks two inches apart will be placed on this section, and then the section will be quickly stretched until the marks are eight (8) inches apart and immediately released. The section will then be re-marked as at first and stretched to eight (8) inches and will remain so stretched ten (10) minutes. It will then be released, and ten (10) minutes later the distance between the marks last applied will be measured. In no case must the test piece break or show a permanent elongation of more 298 Aik-Brake Catechism than % i ncn between the marks last applied. Small strips taken from the cover or friction will be subjected to the same tests. 9. If the test hose fails to meet the required tests, the lot from which it was taken may be rejected without further ex- amination and returned to the manufacturer who shall pay the freight charges in both directions. If the test hose is satisfactory the entire lot will be examined, and those com- plying with the specifications will be accepted. CHAPTER X. THE SWEENEY COMPRESSOR Q. What is the object of the Sweeney device? A. To recharge a main reservoir quickly in descending very heavy grades when the air pressure is low. Q. Explain the parts. A. It consists of a pipe running from the steam chest to the main reservoir. In the pipe there is a cut-out cock, a safety valve, and a non-return check. Q. How is it operated? A. By turning the cut-out cock and reversing the engine when steam is shut off. The main cylinders and pistons act as compressors, and compressed air is forced into the steam chest and thence through the pipe connection to the main res- ervoir. Q. What is the objection to this device? A. It is extremely handy in case of emergency, such as low pressure or the refusal of a pump to work. The objec- tion to it is, that smoke, gas, and heat forced into the main reservoir burn out gaskets and get the brake system very dirty. THE WATER BEAKE. Q. What is the Water or La Chatelier Brake? A. It is a brake by means of which the equivalent effect of reversing an engine is produced; that is, the back pres- sure on the pistons acts through the pins the same as when using steam. 300 Air-Brake Catechism Q. Is water actually used at the point where the work of retardation is accomplished? A. No, it is then in the form of wet steam. Q. Where does the water used come from? A. It is taken from the boiler just above the crown sheet. The pressure from above being removed as soon as it leaves the boiler it flashes into wet steam. The compression to which it is subjected in the cylinders produces heat that also tends to change any water into steam. Q. Is the lubricator shut off when the water brake is in use? A. No, it should be kept in operation the same as when using steam. Q. What special care should be taken when using steam after the use of the water brake has been dis- continued? A. To avoid throwing water out of the stack, steam should not be used until the water has had ample time to work out. Q. Can a water brake be used on either a simple or compound engine? A. Yes; Fig. 114 shows its application to a simple and Figs. 115 and 116 to a compound engine. WATER BRAKE ON SIMPLE ENGINE. Q. What part does the water play after it takes the form of wet steam? A. As the pistons move back and forth the wet steam in the exhaust cavities (Fig. 11-1) is drawn into the cylinders. Q. How does it escape from the cylinders? A. Through the cylinder cocks. Q. If it were not for the wet steam being drawn into the cylinders when the engine is reversed, while using the water brake, what would happen? A. Cinders and smoke would be drawn into the cylinders The Water Brake 301 and in a short time they would be cut and ruined. Q. How should an engineer proceed to put the water brake in use? A. The cylinder cocks should first be opened and should -l — .s. eamport/' "——'TSxhaiist* port y ^•^Steamport J£xhaust~- ^~~— _~ f \s.vort - / | a ; Note.- Drillk 2 hole in \ / h''x y"T for drainage \ l M \ i Fig. 114. — Water Brake on Simple Engine. 302 Air-Brake Catechism remain open as long as the water brake is in use; the reverse lever should be moved back of the center the desired amount and the globe valve (Fig. 114) should be opened immediately. Q. When should the water brake be put in use? A. When the train is moving slowly. Q. At how fast a speed is it practical to operate a water brake? A. It is not generally used at speeds in excess of 14 to 22 miles per hour, Q. How far should the reverse lever be moved back of the center? A. This depends upon the amount of work that is required. The farther back the lever is moved the greater the power. Q. How much should the globe valve (Fig. 114) be open to obtain the right amount of steam in the cylin- ders? A. It should be adjusted until the steam issuing from the cylinder cocks is a dense white. Q. What will be the character of escaping steam at the cylinder cocks if too little water is being used? A. It will be a light blue in color. Q. How can it be told if too much water is being used? A. Water will be thrown out of the stack. This is es- pecially noticeable if the lever is very near the center. Q. What is the purpose of the 1-32-inch hole drilled in the %x%-inch tee, as indicated (Fig. 114)? A. To permit any condensation to escape. Q. In erecting the piping what special care should be observed? A. Care should be exercised to locate the %" x %" tee in the center to insure the same amount of water reaching The Water Brake 303 eacli cylinder; otherwise the tendency would be for one side of the locomotive to furnish more retarding power than the other. Fig. 115. — Baldwin Water Brake for Compound Engine. 304 Air-Brake Catechism THE BALDWIN WATER BRAKE FOR BALDWIN COMPOUNDS. Q. Does what has been said in general concerning the water brake for a simple engine also refer to the Baldwin Water Brake? A. Yes, and with this as with the other, the holding power Pig. 116. — Baldwin Water Brake for Compound Engine. The Water Brake 305 is due to the engine being run reversed, but in full reverse position, the water being used as herein explained. Q. Explain the cuts (Figs. 115 and 116) referring- to the water brake for compounds. A. Fig. 115 is a side view of the front end and Fig. 116 is an end view. When water is permitted to enter pipe A (Figs. 115 and 116) it finally reaches a a, where it enters the exhaust passages. D (Fig. 116) is a gate or back pres- sure valve, by means of which the engineer can regulate the amount of back pressure against which the pistons will oper- ate. E is a safety valve located in the live steamways to per- mit any back pressure above a given amount to escape. C (Figs. 115 and 116) are air inlet valves, which when neces- sary permit air to enter the cylinders and prevent smoke and cinders from being drawn in. B (Fig. 115) is a hinged lid used to close the exhaust nozzle. Q. How is the brake put to work? A. The initial steps are the same as with the water brake on simple engines: open cylinder cocks, put reverse lever in extreme backward position, and open the water valve. The exhaust nozzle lid B should also be closed, and the air inlet valves C be opened. Q. Trace the passage of the water or steam. A. As air enters the inlet valve C (Fig. 115) it mingles with the hot water and steam entering the exhaust cavities from a a. From here it passes by the piston valve G and enters the low pressure cylinder. When the movement of the piston in the low pressure cylinder is reversed this combina- tion of steam, water and air, excepting that which escapes at the cylinder cocks, is compressed while the other end of the cylinder is being filled. The steam being compressed passes by piston G and on, as indicated (Fig. 116), into the oppo- site end of the high-pressure cylinder H. On the return 306 Air-Brake Catechism stroke of the piston it is forced from the high-pressure cylin- der by the piston valve and on into the steam pipe J J, where what does not escape at the back pressure valve D accumu- lates. The safety valves E take care of any pressure in excess of a safe amount. Q. How is the water brake operated on a two cylinder compound of the Schenectady type? A. Generally two water pipes are used on account of the vast difference in the sizes of the two cylinders, and the ex- haust valve between the receiver and the low pressure exhaust passage is left closed while using the water brake. Otherwise the water brake is used practically the same as on a simple engine. LUBRICANTS. Q. What lubricants should be used in the different brake apparatus? A. Steam Cylinder of Pump — Valve Oil. Air Cylinder of Pump — Valve Oil. Brake Valve — High-grade Machine Oil. Triple Valve and High-speed Eeducing Valve — High- grade Mineral Oil in the cylinder, and a very fine dry graphite on the slide valve. Brake Cylinder — A light grease that will not flow in Summer or become thick in Winter. AIR-BRAKE RECORDING GAGES. Q. What is an air-brake recording gage? A. It is a mechanism by means of which lines are traced upon a chart. An examination of these lines will tell exact- ly how the brakes have been manipulated by the engineer. Q. What causes the lines to be traced upon the chart? Recording Gages 307 A. The contrivance has an arm containing a pen which is raised or lowered as the pressure fluctuates in the place to which the gage is piped. As the pen and chart move, a line is traced showing the variation of the pressure. Q. What causes the chart to move? A. It is connected with a clock movement, by the adjust- ment of which the movement of the chart is controlled. Q. To what else is the recording gage similar? A. To a steam indicator; but in that case steam instead of air causes the pen to rise or lower as the pressure changes, and the movement of the main steam piston imparts a move- ment to the indicator drum upon which paper is fastened, and upon which a line is traced by a pen or pencil. Q. To what part of the air-brake system is the record- ing gage piped? A. It may be piped to the brake-pipe the auxiliary re- servoir, or the brake cylinder. On a passenger train, the gage is usually placed at the rear of the train, while on a freight train it is placed in the caboose. Q. Which of these places is preferred? A. The brake-pipe. So connected, the chart shows the fluctuation of pressure when the brakes are applied and re- leased, and the exact habits of the engineer are shown. Q. From the record made by a recording gage, what may be ascertained? A. The amount of brake-pipe pressure carried; the cor- rectness of the air gage ; the method employed by the engineer in the application and release of the brakes; the position of the brake-valve handle in releasing brakes and recharging the train; it is a valuable adjunct in finding the cause of air- brake wrecks or "failures" ; shows if the air-brake instruction of the road is lived up to ; shows how long it takes to recharge with the different main. reservoirs and pumps on the different 308 Air-Brake Catechism engines; it is a valuable aid in discovering the cause of slid flat wheels; it increases the interest of the engineers in air- brake matters, as their record and skill are shown by the lines on the chart; besides these things, a great deal of kindred information may be gleaned by a careful study of the charts. Eecokding Gages 309 Q. At what speed does this chart usually move? A. From two and one-quarter to four and one-half inches an hour, as desired, any choice can be met by the manufac- turers. The speed can be adjusted by means of the clock. Q. Is there any advantage gained from a slow or fast movement of the paper? A. A slow movement condenses the record and does not re- quire so large a chart, while a fast movement uses a larger chart, but shows a greater corresponding amount of detail. If a slow movement is used, and the detail is desired at any particular point, such as a water crane or milk depot, the sj^eed of the paper may be adjusted as desired. In Fig. 117, the broken line shows the path the pen would trace if there was a constant pressure of 70 pounds. No pressure is represented by the circumference of the small cir- cle. The figures at the top are a time reference and the figures up and down refer to the amount of pressure. The distance between the lines running up and down repre- sent the time element. The chart (Fig. 117) shows two records on the same run made by two different men. A study of the two shows several points of interest. The best work shows on the card to the right; the card at the left shows that the feed valve was not adjusted properly for a 70 pound brake-pipe pressure, or else the gage was wrong; the card at the right shows three station stops where the engineer made more than a 20 pound brake-pipe reduction^ while the card at the left shows the same thing at six sta- tions, and at almost every station the stop was made by two applications of the brake. The amount of reduction points very strongly to the use of the emergency. CHAPTER XI'. TRAIN INSPECTION Q. Why is train inspection necessary? A. To find and remedy, before trying to handle the train on a grade, any defects that would render its handling un- safe ; part of the pistons may be out against the cylinder heads when the brakes are applied, the retaining valves may be poor, some brakes may not apply, auxiliaries may not charge, leaks may exist, the brakes may go into emergency when trying to make a service application, and many other defects may exist. Q. Where should we begin to get a train ready? A. At the rear. Q. Is it wrong to start at the head end? A. It would not be were the cocks not opened between the tender and cars. If the cocks were opened, the air would blow through and out of a chance open cock, and a loss of time and air would result. Q. Commencing at the rear, what should be done first? A. The rear angle cock must be closed and the hose hung up. Q. What harm is there in allowing the hose to drag? A. It collects dirt and cinders, which are blown into the train and help to close strainers, and which work into the triples and cause them to wear faster. In winter, ice getting into the hose may block it. Q. What should we do as we go towards the engine? A. See that the retainer handles are turned down, hand Train Inspection 311 brakes released, hose coupled, and cocks turned so that the cars are cut in. Q. How does the cock in the cross-over pipe, connect- ing the brake pipe to the triple, usually stand when the car is cut in? A. At right angles to the pipe. Q. How should the angle cocks stands at the end of the car when cut in? A. Parallel with the pipe. Q. Do the angle cocks and cut-out cocks always stand as just described? A. No ; sometimes in just the reverse positions. Q. Why is this? A. These are cocks used with very old equipment and may be readily recognized, as they differ in shape from those now employed. If in doubt, look at the crease in the top of the plug, which always stands parallel to the opening in the valve. Q. What should we always do before coupling the hose between the engine and cars? A. Blow out the brake-pipe on the engine to get rid of dirt and water. Q. After coupling the hose and turning the angle cocks, are we ready to look over the brakes? A. No, not until the pump has charged the train. Q. With a constant pressure of seventy pounds in the brake pipe, how long should it take to charge one auxiliary reservoir from zero to seventy pounds with the modern equipment? A. About seventy seconds. Q. How long does it take to charge a train of twenty cars? A. This depends on the condition of the pump and the 312 Air-Brake Catechism leaks in the train. If the capacity of the pump were sufficient to keep a constant brake-pipe pressure of seventy pounds, twenty cars could be charged as quickly as one. This can- not be done, as twenty feed grooves usually take air from the brake-pipe faster than the pump will supply it. Q. Who should tell when it is time for the test? A. The engineer. He should wait until full pressure is obtained and then make a twenty-pound service reduction. Q. What should then be done? A. One brakeman should go over the train turning up the retainer handles, while the other examines piston travel and looks for leaks. Q. What should the piston travel be? A. If no rule exists on your road in regard to this, a pis- ton travel between 5 and 8 inches will be found to give good satisfaction on ordinary grades. Q. What should be done after the retainer handles are raised and the piston travel adjusted? A. The engineer should be signaled to release, and then there should be a wait of fifteen or twenty seconds, to allow the brake-cylinder pressure to reduce to what the retainer holds. Q. What should then be done? A. The man on deck should turn down the retainer han- dles. If a blow issues from the retainer when the handle is turned down, the retainer is working properly. A strict count of those working should be kept. The man on the ground should walk along and see that the brakes release when the retainer handles are turned down. Q. What should be done after the inspection is com- pleted? A. A report should be made to the engineer and conduct- Teain Inspection 313 or, giving them a knowledge of the piston travel, the num- ber of retainers in working order, the number of cars, the number of air cars in working order, and the tonnage and any general information concerning the condition of the train. Q. In testing, would it do for a brakeman to open the angle cock at the rear of the train to set the brakes? A. This is decidedly a poor practice; brakes that cannot be worked from an engine will sometimes work by opening an angle cock. If a hose lining were loose, a brakeman might apply the brakes and an engineer release them all right, while in making the reduction from the engine, the brake-pipe re- duction going ahead might roll up the lining and close the hose. We want to know just how the brakes will work from the engine. Q. If there is a leak in the hose couplings, what should be done? A. Turn angle cocks, break the coupling, and, if the seat is bad and there is no extra hose gasket, make the seats round, if they are not so, and recouple. If the leak still exists, break the coupling, put a small stick back of each lug, and close the couplings on them., Q. Why should paper never be used to make a joint? A, It works into strainers, often causing an auxiliary-re- servoir to charge slowly, and it may prohibit getting quick- action on this car. Q. When inspecting a train, if we find a brake that does not apply with the rest, what should be done? A. See that the car is cut in properly, and try the drain cock to see that there is air in the auxiliary reservoir. If the auxiliary is charged, signal the engineer for a brake-pipe re- duction. Q. If the brafee applies and then leaks off gradually, 314 Air-Brake Catechism without any air coming out of the triple exhaust, what is probably the trouble? A. The air is blowing by the packing leather in the brake cylinder. Q. How can a brake that does not apply when the re- duction is made sometimes be made to work? A. By cutting it off from the car ahead and the one behind it and opening the angle cock. The cylinder may be dirty, and setting the brake in the emergency may loosen the dirt and cause it to work properly. Q. If the auxiliary reservoir were found to contain no air when the drain cock was opened, what might be the trouble? A. The feed grooves might be corroded shut in the triple; the strainer where the cross-over pipe joins the main brake- pipe, or the one where the cross-over pipe joins the triple, may be filled with dirt and scale. Q. Is it good practice to pour oil into a hose to make a brake work? A. Decidedly not; it may occasionally furnish temporary relief, but it will decay the rubber-seated valve in the triple and dampen the strainers, pipe, and triples so that dirt will adhere to them and render them sticky. Q. Is a small leak, one that the pump will easily over- come, more easily managed in a long or a short train? A. In a long train. Q. Why? A. Because there is a much larger volume of air in a long brake-pipe, and the reduction causing the brakes to leak on harder after being applied will be much slower on a long than on a short train. Frequently a leak that could not be gotten along with in a train of three or four cars, if cut in with twenty tight cars, would not be noticed. Train Inspection 315 Q. If a retainer were broken off and the pipe plugged, what would result? A. After the engineer applied the brake, he could riot re- lease it, as the exhaust port would have been closed. Q. Would it interfere with applying the brake? A. No. Q. If a brake sticks, what should be done? A. Look to see that no retainer handle is up, that the hand brake is not set, and that no lever is caught. Then signal the engineer again to release. If he is unable to release it, cut the car out and bleed it. Q. Should a car be bled when cut out? A. Always; a leakage of brake-pipe pressure between +be cut-out cock and the triple might cause the brake to apply after it was cut out, if any air were left in the auxiliary-reser- voir. Q. If the piston stays out on a car after we hear the air escape from the triple exhaust port, what is wrong? A. The release spring is probably weak or broken. Q. Is it necessary to cut such a brake out? A. No ; the jar of the wheels against the shoes will force the piston in. Q. If two hose couplings are frozen together, how should they be separated? A. The ice should be thawed, or the gaskets will be torn. Q. If a triple fails to work because it is frozen, what should be done? A. It should be thawed and the drain plug removed in the bottom of the triple, to remove the water and avoid a repeti- tion of the trouble. Q. What three things would cause the brakes to go 316 Aie-Brake Catechism into emergency when making a gradual brake-pipe re- duction? A. A weak graduating spring, a broken graduating pm, and, by far the most likely, a sticky triple. Q. How would we find the triple causing the trouble? A. On a train of five or six cars we can watch to see which brake grabs first and cut the car out. On a train of over seven cars, the brakes do not usually apply with the first re- duction on the car causing the trouble, so, to find the faulty triple, have the engineer make a five-pound brake-pipe re- duction, find the car with the brake not set and cut it out. Then try again with all cut in to be sure that the faulty triple has been found. Q. How would we find the faulty triple if the brakes went into quick action with the first reduction on a long train? A. Turn an angle cock in the middle of the train and see which half contains the trouble; continue in this manner until the trouble is located in a five car lot; have the brakes applied and watch these five as already described, cut out the defective brake. Q. If the emergency has been used, or we find a car cut out, and, when we cut it in, a strong heavy blow issues from the triple exhaust and at the same time the brake sets on the car and cannot be released, what is the trouble? A. The emergency piston is stuck down, holding the em- ergency valve from its seat. Q. How can we close it? A. Tap the triple lightly. If this does not work, turn the cut-out cock in cross-over pipe until the blow stops and then cut it in suddenly; the sudden flow of air may close the valve. Teain Inspection 317 Q. In trying the brakes on a passenger train, how should the signal be given? A. From the head car to apply them and from the rear car to release them, to be sure that the whistle-line cocks stand right throughout the train. On an excursion train the signal should be tested from every car in the train. Q. Explain a means by which poor brakes can be de- tected. A. By feeling of the wheels at the foot of a grade. Q. What will characterize the wheels on the cars hav- ing the poor brakes? A. They will be cold, or cooler at least, than the others. Q. What is this test called? A. The thermal test. Q. Would we expect to find the same degree of heat in all the wheels? A. No; the heavier cars will have the greater braking power as compared with the lighter ones, and these cars would naturally have warmer wheels. This test, nevertheless, is a very valuable aid in detecting j)oor brakes. Q. How would you account for it if a test was made at the top of a grade and all the brakes applied, but some of the wheels were found to be cold when making the thermal test at the foot of the grade? A. One of four chief causes is generally responsible for this condition — low braking power, poor packing leathers, poor retainers, or triple feed grooves in a dirty condition. Q. What could dirty feed grooves have to do with the cool wheels if the auxiliary reservoirs charged all right and the brakes applied properly at the top of the grade? A. In the usual yard test air enough will leak by the 318 Air-Brake Catechism triple-piston packing ring and charge the auxiliary reser- voir so that the brakes will apply properly even if the feed groove is dirty. In descending a heavy grade there are but a few seconds in which to recharge between brake applica- tions; as a result the reservoirs on the cars are never re- charged after the first application that is made on the grade, and the brakes on these cars are, as developed by the thermal test, practically useless, although they did pass the first test. TRAIN HANDLING. Q. What should we always do before coupling to a train? A. Start the pump and be sure that everything is work- ing properly. Do not wait to discover pump or engineer's valve defects when your train is in and ready to proceed. Q. How should an engineer handle the brake on his engine in coupling to a train? A. In backing onto a train, especially an empty one, he should make two or three applications of his driver and ten- der brakes, and leave his valve on lap when coupling to the train. Q. Why is this done? A. To couple to the train with reduced auxiliary pres- sures. Wljen the cocks between the engine and tender are turned, in coupling a train to an engine, the brakes are usually ap- plied on the engine and tender on account of the reduction caused by the air flowing back into the train. If the brake- pipe is long and empty, the main-reservoir pressure might flow back and equalize with that in the brake-pipe at so low a pressure that it might not be able to overcome the tank and driver auxiliary pressures so as to force these triples to re- Train Handling 319 lease position. In this case the two brakes would be stuck, and if more cars were to be picked up, we would have to wait to pump up, or get down and bleed these two brakes off. If we had backed onto the train with reduced auxiliary-reser- voir pressures on the engine and tender, we would not have met with this trouble, as the. main-reservoir pres- sure could then have raised that in the brake-pipe sufficiently to have released the brakes. Q. What should be done after getting our cars placed in the train? A. We should wait until everything is fully charged. Q. How can we tell when the train is charged? A. The pump will nearly stop; or place the valve on lap, and if everything is charged the black hand will not fall. Q. What should then be done? A. A thorough test of piston travel, leaks, and retaining valves should be made before attempting to handle the train on grades. Q. How much reduction should be made? A. A gradual twenty-pound reduction. Q. Why is it necessary to make a test? A. A part of the pistons may be traveling against the cylinder heads, the travel may be too short, the retainers may not be good, or there may be something wrong with a triple that would throw the whole train into emergency when the service application was desired, in which case freight might be shifted or broken, esjDecially in a train partly equipped with air brakes. Q. In testing brakes, from what point should they always be applied and released? A. From the engine. Q. How could it happen that a brakeman could turn 320 Air-Brake Catechism an angle cock at the rear of the train and apply the) brakes, and an engineer could release them, but that the engineer could not set them from the engine? A. The lining of a hose might be loose, so that the en- gineer could throw air back into the train to release the brakes, hut when a reduction was made, the air flowing in the opposite direction might roll the lining up and close the hose. Q. Is this a common occurrence? A. No, but it is by no means unheard of. Q. What else should always be tested? A. The brake-pipe, to see if it leaks, and how much. Q. How should this be done? A. By making a seven-pound reduction in service posi- tion and then placing the valve on lap. Watch the black hand, and the fall of it will show the leak in the brake-pipe. Q. Will not a leak in the brake pipe show if the valve is simply lapped without first applying the brakes? A. It will in time, but not nearly so quickly as by the other way. Q. Why not? A. If the valve is simply lapped, the brakes are not ap- plied, the triples are in release position, and the feed grooves connect the auxiliaiw-reservoirs and brake-pipe. If there is a leak in the brake-pipe with the triples in release position, the air from the auxiliary-reservoirs will leak through the triple feed grooves back into the brake-pipe, and not only the brake-pipe but the auxiliaiy-reservoir pressures will have to be reduced before the black hand on the gauge will register the leak. Q. Why is the other way quicker? A. If the brakes are first applied and the valve then placed Train Handling 321 on lap, the feed grooves in the triples between the auxiliary- reservoirs and brake-pipe have been closed and the leak sim- ply has to reduce the brake-pipe pressure when the black hand will register the leak. With a large volume of air a given leak will reduce the pressure much more slowly than the same leak drawing air from a smaller volume. Q. Just as soon as a train tips over the summit of a hill, what should be done? A. A reduction of brake-pipe pressure should be made to be sure that no angle cocks have been turned and that the brakes take hold properly, also to get the use of the retainers as soon as possible. Q. How can we tell if the angle cocks back of the tank are properly turned? A. By the sound of the brake-pipe exhaust. The more cars of air the greater the volume of air in the brake-pipe, and the longer the equalizing piston will have to stay up to make a given reduction. Q. What should be done if the brakes do not hold properly, or we know by the brake-pipe exhaust that an angle cock has been closed? A. Blow brakes before the train ^ets to moving fast. Q. How much reduction should be made for the first? A. Not less than five pounds, unless Iv triples are in use, and after we get over fifteen cars it is better to make a seven- pound reduction. Five pounds using K triple valves will apply all brakes on trains unless of exceptional length. Q. In a part air train, what would be the harm in starting with a ten-pound reduction? A. The brakes setting hard on the air-brake cars would cause the slack on the non-air cars to run up hard, causing a jar that would be likely to damage the car or the contents, to sav nothing 1 of the effect on the crew in the caboose. 322 Air-Brake Catechism Q. Why is a light reduction, when not using K type of triples, liable not to set the brakes, especially on a long train? A. Because, with a large volume of brake-pipe pressure, reductions are made so slowly that there is a tendency for auxiliary-reservoir pressure to feed through the triple feed grooves into and equalize with that in the brake-pipe, in which case the triple pistons would not move; or, if they did, the air going from the auxiliary-reservoir into the brake cylinder very slowly would blow through the leakage grooves past the pistons and out to the atmosphere. Q. How much should be made for the second reduc- tion? A. This is governed largely by circumstances, but the best results with long trains will be gotten if no very light reduc- tions are made. If the reduction is being made on a long train and the packing rings of some of the triples are a little loose, there is a tendency on the part of the auxiliary- reservoir pressure, that should go to the brake cylinders, to leak back into the brake-pipe by the packing ring. Q. We continue our brake-pipe reductions until finally our brakes are fully set, that is, all the auxiliary reser- voir and brake-cylinder pressures have equalized. How much reduction is usually necessary to accomplish this, if the piston travel is not over 8 inches? A. About twenty pounds, if it is made with one reduc- tion; but in handling a train on a grade, if we needed to get all we could, it would be permissible to make a twenty-five- pound reduction. With K triples 17 and 22 pounds reduc- tions are sufficient. Q. Give the reason for this last statement. A. In descending a grade, we may have gone one, two, or three miles, while we have been making a twenty- Train Handling 323 pound reduction. Naturally, some of the air put into the brake cylinders has escaped by the packing leathers to the atmosphere in going this distance, and making another brake- pipe reduction will let more auxiliary-reservoir pressure to the cylinders. Where the twenty-pound reduction was made with one reduction, the air had no time to leak away by the cylinder packing leathers. Q. Suppose we had already made a twenty-five-pound reduction and the packing leathers in the brake cylinders were practically tight, if we continued taking air from the brake pipe, would the brakes be set any harder? A. No. Q. Would we lose any braking power? A. Yes. Q. How would we lose braking power? A. The brake is already fully set, that is, the auxiliary- reservoir and brake-cylinder pressures are equal; with a fur- ther reduction of brake-pipe pressure, no more auxiliary-res- ervoir pressure can go to the cylinder; but just as soon as the auxiliary-reservoir pressure is enough greater than that in the brake-pipe to overcome the resistance of the graduating spring in the triple, the triple piston will be forced to emergency position, and we will have a direct connection between the auxiliary-reservoir and brake cylinder through the emergency port in the end of the slide valve. The brake-pipe pressure being less than that in the auxiliary-reservoir and cylinder, both these pressures will begin leaking by the packing ring of the triple piston into the brake-pipe. Q. Is there any other way in which we would lose braking power by too heavy a brake-pipe reduction? A. Yes; the brake-pipe check in the emergency part of the Westinghouse triple is seldom air-tight, owing to cor- rosion. When the brake-pipe pressure is less than that in 324 Air-Brake Catechism the brake cylinder, the brake-cylinder pressure forces the rub- ber-seated valve from its seat and leaks by the brake-pipe check into the brake-pipe. Q. Is there usually any warning to let the engineer know he has made too heavy a reduction? A. Yes; especially on a long train, where there are more packing rings to leak. q. What is it? A. Under these circumstances, a blow at the exhaust at the brake valve results. Q. What causes this exhaust? A. The engineer reduced the equalizing-reservoir pressure in order to cause the equalizing piston to reduce the brake- pipe pressure. It closed the exhaust when the brake-pipe was a trifle less than the equalizing-reservoir pressure. When too heavy a brake-pipe reduction had been made, we saw that the auxiliary-reservoir and brake-cylinder pressures fed back into the brake-pipe. The brake-pipe now being greater than the equalizing-reservoir pressure, the equalizing piston is moved from its seat, and the blow at the brake-pipe exhaust continues as long as air is feeding into the brake-pipe from the auxiliary-reservoirs and brake cylinders. Q. Does the equalizing piston always move and give this warning? . A. No; if there is leakage by the equalizing piston, the air feeds by and equalizes the equalizing-reservoir and brake- pipe pressures, but the braking power is lost just the same. Q. Is the triple piston supposed to form a joint on the leather gasket between the triple head and the main body of the triple? A. Yes, when the gasket is new, but the gasket dries out so that the surface is not smooth. Train Handling 325 Q. What places should we pick out, if possible, in which to recharge? A. Where the grade lets up a little and on curves where a train binds. Q. To release brakes, where should the handle of the engineer's valve be placed? A. In full release position. Q. How long should it be left here? A. This is governed entirely by the length of the train. If, in descending a grade, both hands on the gage shows that the brake-pipe and main-reservoir pressures equalize below seventy pounds, the valve should be left in this position until both hands start to go above seventy. If the pressures equalize about seventy pounds when the valve is thrown to full re- lease and stay there, the valve should be moved to running position as soon as the brakes are released, so as not to over- charge the auxiliary-reservoirs. Q. Why, on a long train, should the valve be left in full release position until both hands start above seventy pounds? A. A large port connects the main reservoir and brake- pipe in this position and a small one in running position, and we get the benefit of the excess pressure from the main reservoir in recharging; the pump works faster, and we can charge the train much more quickly, because the brake-pipe pressure being higher forces air into the auxiliaries faster. Brakes are likely to stick and wheels slide, especially on a long train, if we try to release brakes in running position. Q. Why does the pump work faster? A. Because there is less main-reservoir pressure for it to work against. Q. Why do the last three or four pounds feed more 326 Air-Brake Catechism slowly into the brake pipe, if the valve is put in running position? A. Because when, in running position, the brake-pipe pres- sure is almost up to that at which the feed valve is adjusted, the spring in the feed valve begins to be compressed and al- low the little regulating valve to partly close, in which case the pump will compress air faster than it can get through the feed valve. When the main reservoir is charged to ninety pounds, the pump practically stops, and this is likely to hap- pen before the auxiliary-reservoirs are fully recharged. Q. Why will some brakes stick in trying to release them in running position? A. Because the brake-pipe pressure rising slowly may feed by some triple piston-packing rings, and allow auxiliary- reservoir pressure to keep equal with that in the brake-pipe. Q. Why may the wheels slide in this case? A. Because the brake on this car has been left fully set and the auxiliary-reservoir fully recharged. A five-pound reduc- tion will probably set this brake in full with a pressure of sixty-five pounds, and this is more than is safe, especially with a light car. If a brake once sticks it is very likely to remain stuck, as the auxiliary-reservoir and brake-cylinder pressures equalize so high that it requires a higher brake-pipe pressure to release this brake, and the brake-pipe pressure in- creasing slowly, gives the air a better chance to leak by the triple-piston packing ring. A brake acting this way may be all right if handled properly. Q. In descending a grade after getting the use of the retainer and having everything recharged, why is a five- pound reduction much more effectual than a five-pound reduction made without the use of the retainer? A. Because in one case we are putting five pounds from the auxiliary reservoir into fifteen pounds in the cylinder,, Train Handling 327 and in the other we are putting five pounds from the auxiliary reservoir into an empty cylinder, and a part of that put in blows through the leakage groove before the piston travels far enough to close it. Q. If a twenty-pound brake-pipe reduction will apply a brake in full without the use of the retainer, how much reduction ought to set brakes in full after getting its use? A. Not over fifteen pounds. Q. If all retainers are being used, is it necessary after charging up to make a five or seven pound for our first reduction? A. Yes, with old equipment, some of the retainers might have been out of order, so as not to hold any air in the cylin- der, and less than a five-pound reduction would not catch these brakes again. Q. What should an engineer do, if, when he is not using the brakes, he feels them applying so as perceptibly to diminish the speed of the train? A. He should place the handle of the engineer's valve on lap. Q. Why? A. Probably a hose has burst, or the conductor is using the conductor's valve. If the valve is not lapped, the main- reservoir pressure will be lost, and there will be no pressure with which to release the brakes and recharge the auxiliaries. Q. Which is less dangerous, a leak that will gradually slow a train up, or one that will simply keep the train running steadily? A. A leak that will slow a train up is much to be preferred. Q. Why? A. If the leak simply runs the train steadily and the engineer allows the pressure to gradually leak away because he seems to be making a nice, even run, he would have a dif- 328 Air-Brake Catechism ficult time stopping the train if necessity demanded it, after the pressure had leaked down to fifty pounds. Q. Should an engineer try to make as uniform a run with air as can be done with hand brakes? A. As a rule, no, although on some light grades a few re- tainers will run them smoothly. On heavy grades and long trains it is necessary to slow up to recharge. It will be found that a much more uniform run can be made with K triple valves, as lighter reductions result in a more positive response and a higher cylinder pressure is developed for a given reduction, hence it will not take so long to recharge, and the speed can be maintained more uniform. Q. What should always be done, where possible, in making brake-pipe reductions? A. Watch the gage. Q. How do you account for the fact that sometimes, after a seven-pound reduction of equalizing reservoir pres- sure is made and the valve lapped, the gage records only a five-pound reduction when the * brake-pipe exhaust closes? A. The equalizing piston has allowed brake-pipe pressure to feed by it into the equalizing reservoir. Q. Is this more likely to happen on a long or a short train? A. On a long train. Q. Why? A. As there is a greater volume of air in the brake pipe of a long train, it takes longer to reduce the pressure, and the brake-pipe pressure has a longer time to leak in the manner described. Q. If a quick reduction is made in emergency with the engine alone, and the valve is then placed on lap, why is Train Handling 329 the tank or driver brake likely to kick off, although they would stay set in service application? A. In emergency position, air is drawn directly from the brake pipe without taking any from the equalizing reservoir. When the valve is placed on lap, the equalizing-reservoir pres- sure leaks by the packing ring of the equalizing piston, raises the brake-pipe pressure, and kicks off one or both brakes. Q. Why will this happen on an engine and not on a train? A. The volume of air in the brake pipe of an engine alone is very small, and a slight leak into it is sufficient to raise the brake-pipe pressure and release the brake. With a train, the brake-pipe volume is so large that the leakage into it from the equalizing reservoir is not sufficient to affect the triples. Q. The release of the brakes on the engine alone, after the use of the emergency, is ascribed by some to the surge of air. Is this the cause? A. No; a surge of air would release the brake almost in- stantly. The brake does not release sometimes until five or ten seconds have passed. Q. Why will this happen on one engine and not on an- other? A. This simply means that on one the triple piston-pack- ing rings are looser than that in the equalizing piston, and the brake-pipe pressure feeds by the triple piston and equal- izes with that in the auxiliaries. A variation in the fit of the equalizing-piston packing rings on the different engines would also account for this. Q. The above usually happens when stopping an en- gine at a water-crane or on a turntable. How are these stops best made with the air? A. One application is best to use with an engine alone. 330 Air-Brake Catechism If we find that we are stopping three or four feet short, open the throttle, and the engine can be helped along a short distance and a smoother stop be made. Q. What happens every time you use the emergency on a turntable? A. You strike the table a blow which is the result of the weight and the speed of the engine, and then ? if the turn- table breaks down, wonder why the company does not pro- vide a decent table. Q. In making a water-tank stop with a passenger train, how should it be done to avoid a jar to the train and pas- sengers? A. The stop should be made with two applications of the brake, when using the old equipment, unless the grade is too steep and the pressure too low for safety. With the gradu- ated release triple the brake is set with a high pressure, and this pressure is graduated off as the stop is approached. It may be necessary to make another reduction; if so, the re- sponse is quick as the shoes are already against the wheels, there is pressure in the cylinder and the L triple contains the quick-service feature. Q. How do we handle the valve to make the first re- lease so that the brakes will respond with the first reduc- tion when using old equipment? A. When the speed of the train has been reduced to that desired, throw the valve handle to full release and bring it back on lap immediately. Q. Why bring it back on lap? A. So as not to raise the brake-pipe pressure too high. The feed grooves in the triples are small, and have only three or four seconds in which to equalize the brake-pipe and auxiliary-reservoir pressures. If the valve is left in full release or running position, and the brake-pipe pressure gets Train Handling 331 to seventy pounds, and there is, say, only fifty-five pounds in the auxiliary reservoirs, the triple pistons will not move to service position until over a fifteen-pound reduction of brake-pipe pressure has been made. By the time we have made this amount of reduction in service position we shall have gone by the water-crane, unless we use the emergency, and that is what is usually done if the engineer is not up to date. Q. When should brakes be released on a passenger train? A. Just before the train stops. Q. What should be done on a grade just heavy enough so that the train will start with the brakes released or with a train of more than ten cars. A. Stop the same as at a water-crane. No jar will be felt with a light application. With the L triple valve the pressure may be graduated down to that just sufficient to cause the train to remain at rest. Q. How about a heavy grade? A. Our stop, if we do not have the graduated release feature, will then depend on the grade and our pressure. Safety should be of first importance, even if the stop is a trifle rough. Q. What makes the jar, if the brakes are not released before the train stops? A. With the brakes set hard, the trucks are distorted, and it is the struggle of the trucks to right themselves that causes the jar. Q. Can brakes be started releasing longer before stopping after a light or a heavy reduction? A. After a heavy reduction, as there is more air in the cylinders to be gotten rid of, and the brakes release more slowly. 332 Air-Brake Catechism Q. What is meant by an application? A. It covers all the time from the moment the brake is applied until it is released; three or four reductions may be made during one application. Q. In making a stop with a freight train, when should brakes be released? A. After the train comes to a full stop, to avoid breaking the train in two if the slack runs out hard in releasing before stopping. Q. If we have stopped short with a freight train, and need to release before stopping to pull up farther, what should be done? A. We should wait for the slack to adjust itself in the train before using steam. Even then the steam should be used very cautiously. Q. In running passenger trains over cross-overs to get around freights, what care should be taken? A. To do this, brakes have to be used when nagged, at the upper cross-over, lower cross-over, and usually at a station. We should charge up as much as possible after each application. Do not follow the plan of releasing and putting the valve on lap in such a case to be sure the triples will respond quickly. They will respond quickly, but if the station stop is on a grade, you may not have air enough left to make it when you get there. Q. What is the usual cause of trains running away? A. Making a great many reductions without occasionally charging up; or allowing the pressure to leak away, because the train is running steady, and then when we get ready to recharge, not having enough air left to slow up the train; by not stopping to recharge when air is gradually being lost and by maintaining too high a speed when the brakes are not holding well, Train Handling 333 Q. On a fast passenger run. how may time be saved in using the brake? A. By waiting longer before applying the brakes and then making a ten-pound reduction at the start. Q. Will this not jar the passengers? A. Not when going fast. Passenger trains are continu- ous, and there is very little slack to run up. A ten-pound reduction made with a train moving ten miles an hour would produce a very unpleasant sensation to passengers, where at forty miles an hour it would not be noticed. This is explained under the subject Old-Style High-Speed Brake. Q. Should brakes be tested in taking on cars? A. Yes, to be sure that the brakes on these cars work properly, and that the brakes back of them can be applied and released through them. Q. When all retainers on a train are not necessary, how should they be used? A. At the head end if the grade is short; otherwise change them around and use them on every other car, so as not to overheat any wheels. Q. If the brakes are applied and the engineer wishes to release and drift two or three hundred feet before stopping, what should be done? A. Enough retainers should be left in operation to keep the slack bunched. This, of course, is not usually necessary, if the engine is equipped with an independent brake. Q. When should hand brakes be used? A. On the rear of a part air train when backing it into a siding; if it stands on a knoll, to keep the slack from running back; to aid the air when the brakes are not holding well. Q. Should hand brakes and air brakes be used together on the same car? 334 Air-Brake Catechism A. This is a risky practice. If the two brakes work to- gether, we are very likely to heat or slide wheels; if they work in opposition, there is danger of a brakeman being- thrown from the car; and the hand brake being applied will take up the slack in the brake rigging, so that the piston cannot get by the leakage groove. Q. If hand brakes be used back of the air, if there are not enough air brakes to control the train, what is likely to happen? A. This is likely to produce a bad effect when the air brakes are released. If the retainers are poor and allow the slack to run out, the train may be broken in two. Q. If hand brakes are to be used with the air, where should they be applied? A. Next to the air. Q. Should driver brakes be cut in when descending a heavy grade? A. Always, or so much more work is thrown on the car brakes. The use of a water brake would, of course, be an exception to this rule. Q. If cut in all the time on heavy grades, would the tires not become overheated? A. In heavy grade work the piping is usually so arranged that a cock can be closed between the triple valve and brake cylinder, or a pipe from the brake cylinder is run into the cab and a cock attached to same. In either case the proper manipulation of these valves will prevent overheating of tires. Q. If an air-brake train should be stalled on a grade, should part of the train be left with air brakes to hold them until the engine comes back? A. No; the air brakes should be released one at a time, 9 — Train Handling 335 and the hand brakes applied. If left with the air holding them, the air might leak off and allow the train to run away. Q. When brakes are fully set, the long travel brakes are easier to release. They may be released and leave the short travel brakes applied. Is this good practice in hold- ing trains? A. ~No; it is very bad practice. A train may be broken in two in this way. Q. If brakes stick and will not release by placing the valve in full release, what should be done? A. Make a full service reduction and then, with a full excess pressure, throw to full release. If a release from the engine is possible, this will accomplish it. Q. The practice is sometimes followed of using hand brakes on some of the air cars to take the place of the re- taining valve. If this is done, how and when should the hand brakes be applied? A. They should be applied so as to hold as nearly as possible what the retaining would accomplish when retaining the proper pressure. If the brakes work "together," and the hand brake is applied when a high cylinder pressure exists the wheels on cars where the hand brakes are used will be called upon to do too much work and undue heating will result. Do not use hand brakes in such a case if the brakes work "opposite." Q. What harm is there in pulling hose apart instead of uncoupling them? A. The couplings are likely to be sprung so that they cannot be coupled again, and the brake pipe is likely to be torn from the car or engine. Q. Does it do any harm to lean on the rotary handle when the brakes are applied? A. Yes; if the dovetail piece that fits into the rotary is 336 Air-Brake Catechism tight on account of dirt and gum, the rotary may be cocked so as to allow main-reservoir pressure to feed into the brake pipe under the rotary and release some of the brakes. Q. What is the trouble, when there is a leak in the brake pipe, if the engine is alone, but coupled to tight cars, the leak does not show? A. The leak is in the angle cock at the rear of the tender. When coupled to a train, the leak is not noticed as the cock is open. With the engine alone the cock leaking allows air to pass out of the hose to the atmosphere. Q. In double heading, which engine should handle the brakes? A. The lead engine. Q. What should the second engineer do? A. Turn the cut-out cock under his valve and under no circumstance, unless in case of accident or when told to, should he cut in and interfere with the work of the lead engine. Q. If the pusher engine has no cut-out cock, what should be done? A. The valve should be placed on lap. Q. In this case, why does the equalizing piston some- times rise? A. Because the lead engineer increases brake-pipe pres- sure to release the brakes, and the increased pressure forces the equalizing jjiston from its seat. Q. How may it be seated? A. By putting the handle in full release position long enough to charge the equalizing reservoir. Q. In case of emergency, when it is necessary for us to leave the engine, what should be done? A. Place the engineer's valve in emergency position and - Train Handling 337 leave it there. In our hurry, if we tried to lap the valve, we might get it into running position and release the brakes. Q. Why ought we never to bring our valve back from emergency position too quickly? A. There might be two or three cars cut out, a couple of plain triples, a contracted passage, or a couple of cars that would not go into quick-action on account of dirty strainers. If these cars were together, they would not help to carry the quick-action back. Generally a quick-action triple will not send a quick reduction through five cars which are cut out. In this case, if the engineer's valve had been lapped too quickly, the surge of air ahead from the rear end would release the head brakes, and all we would have would be a very light service reduction on the cars back of those cut out. If we leave the engineer's valve in emergency posi- tion long enough, we could at least get the full service ap- plication on these cars, and the emergency on those ahead of the cars cut out. Q. Should the engine be reversed when the driver brakes are applied, if we wish to stop quickly? A. No; the following test, made by Mr. Thomas, Assist- ant General Manager of the N., C. and St. L., clearly demon- strafes that the air brake used alone is better than the brakes with the reverse lever, or than the reverse lever alone. The result of these tests was published in the '95 Air- Brake Proceedings, and is given on pages 264 and 265. The conditions of the test were as follows: Driving brake power, seventy per cent.; tender, one hun- dred per cent. ; N., C. & St. L. coaches, ninety per cent. ; Pullman sleeper, forty to one hundred and one per cent. Boyer speed recorder was used and tests were made: first,- brakes applied ; second, engine reversed ; third, sand lever opened. Track was level, in best possible condition, and all circumstances favorable. 338 Air-Brake Catechism From the record of tests the following valuable informa- tion was derived: First. Best stops are made with braking power not quite strong enough to skid wheels. Second. Length of stop is the same in reversing the engine whether cylinder cocks are open or closed. Third. The wheels did not lock rigidly when the engine was reversed without the brakes being used. Fourth. The tests demonstrated that the brakes used alone are better than with the engine being reversed. The stop is quicker, and there are no flat spots obtained. Fifth. Enough sand is much better than too much. Sixth. Sand should be used before wheels start skidding, as its use will not start the wheels revolving when once skidding; it will simply increase the flat spots. Seventh. Sand being used on a straight track, the drivers did not lock when the engine was reversed, but on a curve they would. On a curve the engine rocks, and sand is not so likely to strike the rail. Eighth. In expected emergencies, the drivers did not lock when sand was used before brakes were applied and engine reversed, but it took so long to get the sand running first that, in the end, the stop was not made as quickly as with un- expected emergencies where the engine was not reversed. Ninth. The unexpected emergencies are the ones that bear the most weight, as expected emergencies are practically un- heard of. The table on page 339 will be of interest, as it shows how old and new air-brake trains can be stopped when fitted with air-brake trains can be stopped when fitted with the old and new Westinghouse quick-action freight brake. The train consisted of eighty Southern Pacific oil-tank cars. Brake-pipe .Reduction 5 lbs. 5 lbs. 10 lbs. 10 lbs. 15 lbs. 15 lbs. 20 lbs. 20 lbs. 2/375 4,140 875 1,700 S90 1,890 595 1,090 860 1525 580 1,040 940 1,725 580 1,060 ined during the South Train Handling 339 COMPARISON OF THE NEW (TYPE Iv) WITH THE OLD (TYPE H) EEEIGHT BRAKE EQUIP- MENTS IN ORDINARY SERVICE OPERATION ON 80-CAR TRAIN, Triple Valve Approximate Lenghtof Stop in ft. from speed oft Used 10 M. P.H. 20M.P.H. 30M.P.H. H 860 K 330 H 325 K 215 H 295 K 220 H 365 K 215 Note: The above results were obtained during ern Pacific Brake Tests at Bassett, Cal., in July, 1908, with an 80-car train of empty oil-tank cars, having 10-inch freight equipment and an average standing piston travel of 6.78 inches; brake-pipe pressure 80 pounds. Road bed practical^ level. The results are only comparative and must not be taken to cover all conditions. It will be noted that in some cases the stops are slightly longer for 20-pound reductions than for 10 or 15-pound. This is due to the fact that in some cases the train came to a stop before the reduction was completed. PIPING. Q. What should be done in preparing pipe for use? A. After bending the pipe it should be blown out with steam to get rid of scale and dirt. If there is no steam at hand, air should be used. Under no consideration should pipe be used without first being cleaned. All fins should be care- fully removed to prevent their working loose and clogging strainers. 340 Air-Brake Catechism •sxoas xvijj = S- O - - •» z - - - = * ; s s : : "O tc "0 a! 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