BARRY ON THP] CITY TERMINUS EXTENSION OF THE CHARING CROSS RAILWAY. THE CITY TERMINÜS EXTENSION OF THE OHARING GROSS RAILWAY. BY JOHN WOLFE BAEEY, M. Inst. G.E. WITH AN ABSTKAOT OF THE DISCUSSION UPON THE PAPER. EDITED BY JAMES FOEREST, Assoc. Inst. C.E., SECRETARY. By permission of the Council. Excerpt Minutes of Proceedings of The Institution of Civil Engineers. Vol. xxvii. Session 1867-68. LONDON ; PRINTED BY WILLIAM CLOWES AND SONS, stamford street and charing cross. 1869. [The right of Publication and of Translation is reserved.] ADVEETISEMENT. The Institution is not, as a body, responsible for the facts and opinions advanced in the following pages. LIBRARY EAU OF RAILWAY ECOMOFîCf, VA3HltiGT0íí, O. C. ftfa 4 19]Î he 3o\e( f c f M 3 THE INSTITUTION OF CIVIL ENGINEERS. March 31, 1868. CHAELES HÜTTON GEEGOEY, President, in the Chair. No. 1,198.—" The City Terminus Extension of the Charing Cross Eailway." By John Wolfe Barry, M. Inst. C.E. This extension of the Charing Cross Eailway was projected with two objects in view; first, to give to the whole of the districts served by the South Eastern Eailway Company direct access to the heart of the City, and, secondly, to form a Metropolitan connecting Hnk bstween Charing Cross at the West End and Cannon Street at the East, accommodating by this means the important trafile con¬ stantly passing to and fro between these two central points. (Plate XV., Map.) The convenience afforded to the public may be gathered from the fact that, during the year ending the 1st of January, 1868, being the first year after the railway was opened to Cannon Street, about eight millions of passengers used the Cannon Street Station, of which number about three and a half millions were local passengers booked between Cannon Street and Charing Cross. At the present time about twenty-six thousand passengers use the station daily, and this number may be expected to increase, especially so far as regards the City and West End trafile. The works comprised under the above title were authorized by Act of Parliament, dated June 28th, 1861, and consist, in the order which this description will follow, of (1.) The Bridge over the Eiver Thames. (2.) The Cannon Street Station. (3.) The Viaducts south of the Eiver Thames, connecting the Thames Bridge with the main line of the Charing Cross Eailway. The whole of the works were designed by Mr. Hawkshaw (Past- President Inst. C.E.), the consulting Engineer to the South Eastern Eailway Company, and were carried out tinder his direction, the Author being the Resident Engineer for almost the whole period of construction. Mr. George Wythes (Assoc. Inst. C.E.) was the contractor for the whole work ; but the ironwork generally, together with the erection of the bridge over the Eiver Thames (excepting the abutments), was sublet by Mr. Wythes to Messrs. (Cochrane, Grove, and Co., of Dudley. Messrs. Cochrane's B 2 4 CHARING CROSS RAILWAY, CITY TERMINUS. works were directed by Mr. Joseph Phillips (Assoc. Inst. C.E.), and Mr. Wythes was represented by his agent, Mr. William Canning. The works were commenced in July, 1863, and the Eailway was opened for public traffic on the 1st of September, 1866. Consider¬ able difficulty, involving delay, was at first experienced in obtaining possession of the land, as is often the case in the Metropolis, and the works were further retarded by the requirements of the Thames Conservancy Board, who would not allow more than a certain number of the piers of the bridge over the river to be in progress at one time. THE BEIDGE OVEE THE EIVEE THAMES. (Plates 15 and 16.) The bridge has been constructed to carry five lines of way from the south abutment to the pier next to the Middlesex shore, at which point the five lines branch out on the part of the bridge which is termed the Fan, and are connected with the nine lines of way which are in the station. There are two footpaths, with ap¬ proaches and toll-houses, one on each side of the bridge, fenced off from the portion devoted to railway purposes. They were intended for the use of the public on payment of a small toll, and would no doubt relieve the crowded condition of London Bridge. They were completed at the same time as the railway, but have not yet been opened for traffic. The extreme length of the bridge between the abutments is 706 feet. This length is divided into five spans, measuring from centre to centre of the piers as under, the clear spans being also given:—(Eig. 1.) From centre of Pier to face of Abutment Clear space on on Centre Line. Centre Line. Two side openings . . 131 feet . . 125 feet. From centre to centre of Piers. Three centre openings . . 148 feet . . 136 feet. The width of the straight portion of the bridge outside the foot¬ way parapets is 80 feet, and the width of the railway portion be¬ tween the inside parapets is 61 feet 8 inches. (Fig. 2.) The Fan, which extends over the Middlesex opening, is widened out from an extreme width of 80 feet at the Middlesex pier to 202 feet at the north or Middlesex abutment, and accommodates, in addition to the fines of way, portions of two passeùger platforms, engine sidings, and foreman's offices, &c. The height of the soffit of the bridge above Trinity high-water level varies from 24 feet 8 inches at the abutments to 25 feet 4 inches in the centre span. The top of the pier next the shore on each side is 4 inches higher than the abut- charing crdss railway, city terminus. 5 ment, and the top of the two centre piers is again 4 inches higher than that of the side piers. The object of this arrangement was to prevent the bridge appearing depressed at the centre. The height of the rails above the soffit of the bridge is 9 feet 10 inches. The greatest depth of water at low water was about 13 feet 6 inches, and the difference between Trinity high water and low water is 18 féet. The Abutments. The southern abutment is advanced about 40 feet into the river beyond the general line of wharf frontage. The ground on which it was necessary to build is London clay, lying beneath a depth of about 15 feet of river mud and alluvial deposit. It was decided to build this abutment on cast-iron caissons. This arrangement had the advantage ' inter alia ' of rendering a coffer-dam unnecessary. The size of the caissons, which are square on plan, with rounded corners, is 12 feet by 12 feet. The total height of the caissons is 18 feet ; they are divided into three lengths, each length consisting of eight pieces, and being 6 feet high. The size of the large plates is 6 feet by 8 feet, and the thickness of the metal is l^^g inch. The caissons were sunk side by side without any great difficulty, partly by means of divers working in helmets, and partly by dredging inside the caissons with a bag and spoon dredger. The square form of the caissons is not, in the Author's opinion, desirable where cylinders can be conveniently employed. Considerably more difficulty w^as experienced in keeping the caissons vertical than was the case with the cylinders, and they are weaker, in proportion to the weight of metal employed, than a cylinder enclosing the same area. The caissons were sunk to a depth of 36 feet below Trinity high-water level, the tops being 18 feet below the same datum. York landings were placed on the caissons, and on these brickwork in Portland cement was built up to the level of the bed stones for the girders of the bridge, a height of 42 feet. The north abutment was built without either caissons or coffer-dam; lengths of ground about 30 feet long and 22 feet wide were excavated at low water ; a ' stank ' dam of clay was employed, and the length opened being short, the water which came into the excavation at flood tide was quickly pumped out by a steam pump as the tide ebbed, and a strong force of men was employed to continue the exca¬ vation, or get in the footings, before the tide returned. The depth of the bottom of the footings of this abutment below Trinity high-water is 21 feet 6 inches. The bottom is gravel of excellent quality ; the brickwork is built with Portland cement from the bottom to a height of 7 feet above Trinity high water, from which level it is built with ordinary grey lime mortar. The 6 charing cross railway, city terminus thickness of the south abutment is 12 feet, and of the north abut¬ ment 16 feet. The facing of both is red brick, and the plinth, quoin, arch, and string stones are of Bramley Fall. The Staging for the Bridge. The Conservators of the river would not allow more than two piers to be in progress, or more than two openings to be impeded by staging at one time, and stipulated that in each span a water way of 50 feet should be left in the staging for the passage of craft. These conditions naturally delayed the progress of the works consi¬ derably ; but the traffic at this narrow part of the Thames is so heavy, that any other arrangement would have greatly inconvenienced the public traffic of the river. The staging for the piers was first erected of a width only sufficient for a berth for a barge on each side of the cylinders, with platforms for unloading materials, and as the piers were finished, it was widened out on each side, so as to contract the opening to 50 feet. This was spanned by a timber truss, and a continuous platform was thus formed over each span for the erection of the girders. Great difficulty was experienced in erect¬ ing the staging aná keeping it in order ; and especially in driving the first few piles for each pier. The strength of the tide at this narrow part of the river is great, and the craft, which are very numerous, were continually swept up against the pile barge and the first few piles which had been driven, occasionally carrying away everything before them. în this way the staging for some of the piers was three times commenced, and as often swept away, before it could be made sufficiently strong to resist the attacks of the barges. The Piers. (Figs. 2 to 6.) The piers are each formed of four cast-iron cylinders, placed in a line at right angles to the longitudinal axis of the bridge, and con¬ nected by two wrought-iron transverse girders at the top. The cylinders are for the most part alike, except that the depth to which they are carried varies slightly. The description of one will there¬ fore suffice for all. The outside diameter of the cylinders is 18 feet below and 12 feet above the bottom of the river. A conical re¬ ducing ring is introduced, to efiect the junction between the two diameters. The cylinder plates are fiuted from 5 feet below Trinity high-water mark up to the level of the ornamental cap mouldings. The ordinary rings of the 18-feet cylinders are 9 feet high, and each ring consists of nine segments, which are 6*28 feet measured round the arc. The thickness of the metal generally is 1| inch. The flanges are from 3| inches to 5 inches wide, and 1¿ inch thick. charina cross railway, city terminus. 7 The 12-feet cylinder rings, which are each also 9 feet high, below the fluted portions, are formed in a similar way of six segments, each segment being as above, 6*28 feet measured round the arc. The thickness of the metal is 2 inches. The fluted rings con¬ sist also of six segments, which are considerably stronger and heavier than the others. The reducing ring is formed of nine segments, which are 9 feet high, measured vertically. The metal in the reducing rings is 2 inches thick throughout. The bottom ring of cylinder plates is only 4J feet high, and is of extra strength, with a sharp-cutting bottom edge ; the thickness of metal in this ring is 2J inches. Figs. 2 to 6 show further details of the cylinders. In order that the fluting should begin at the same level in all the cylinders, a special ring of plates was necessary for each cylinder, it being impossible to sink the cylinders with suflicient accuracy to keep the tops of all of them level with one another ; and the subsidence under the test load was not always uniform. This special length was cast after the testing was completed. Sinking the Cylinders. The cylinders were sunk as follows : The bed of the river was smoothed by dredging on the site which the cylinders were to occupy. The two bottom rings, making a height of 13^ feet, which was equivalent to the greatest depth of water, were built up and caulked over their destined position, resting on timbers and between strong timber guides. The cylinder was then raised by a travelling crane so as to permit of the removal of the supporting timbers, and was afterwards lowered into its position on the bottom of the river ; a third ring of plates was next added on the top of the other two rings, and a bag and spoon dredger was worked inside the cylinder. The ground lying over the London clay, consisting of mud and gravel, was by this means taken out and removed in barges, and additional rings of plates being bolted on as the cylinder descended, it was thus sunk through the superincumbent strata until the London clay was reached ; the water was then pumped out and the sinking continued by ordinary excavation until the final depth was attained, which was from 59 feet to 65J feet below Trinity high water. The sinking of some of the caissons and cyhnders through the mud and gravel was, when the works first commenced, carried on by divers working in helmets, but after a short time the dredging with the bag and spoon was adopted, and found to answer its purpose, in many ways, better than the divers. Concrete in Portland cement was put in on the London clay in layers of from 4 feet to 5 feet up to the level of the bottom of the reducing ring, and brickwork of pavior bricks laid in Portland cement was built on the concrete up to the level of 2 feet above low-water mark, 8 charina cross railway, city terminus. where the erection of the cylinders was stopped for testing. The testing, which will he described hereafter, having been finished, the building of the cylinder was continued in the same manner as below the testing line, excepting that fiuted plates were used instead of plain plates, to the underside of the stones which support the bed¬ plate girder. The brickwork was built with a ring of headers round the outside of each course, and the hearting was filled in with ordinary English bond, herringbone courses being occasionally introduced, and care being taken to fit the bricks as accurately as possible round the flanges of the cylinders. The bed-stoñes are fixed on the top of the brickwork ; they are of Bramley Fall, ex¬ cept in two instances, where they are of granite. Each bed stone is in two pieces, and is 24 inches thick. Weighting and Testing the Cylinders. Each of the cylinders was weighted at the testing line with 850 tons of iron. This weight was calculated to represent the dead weight of the structure above the testing line, a rolling-load of one ton per foot forward for each line of way supported by the cylinder, and a moving-load on the footpaths. The weight was appHed liy packing rails, kentledge, and pig iron, on the cylinder. Careful observations were taken before and during the loading. When the whole weight was resting on the cylinder, levels were taken every other day, until it was found that no subsidence had taken place for seven days. The order to remove the load was then given, and the dimensions having been taken for the making-up, or special ring of cylinder-plates, and the ring having been cast, the erection of the cylinder was proceeded with. The greatest subsi¬ dence under the full test-load was 2f inches, and the least ^ inch. The labour of testing in this way every cylinder was considerable, and delayed the progress of the works. The results, however, show the necessity of the precaution. Subsidence was almost invariably observed before, the total test-load had been placed on the cylinder. The heaviest weight on the London clay at the bottom of any of the cylinders is 5*84 tons per superficial foot, with a rolling- load as stated above ; and the heaviest weight on the brickwork in the cylinders is about 9 tons per superficial foot. The Bed-plate Girders. (Figs. 7 and 8.) On the top of the Bramley Fall stones, which form the top of the cylinders, the bed-plate girders are fixed transversely to the axis of the bridge. Each pier has two bed-plate girders, and all of them are alike, excepting that supporting the main girders of the charina cross railway, city terminus. 9 Fan, which is wider and stronger than the others. Thehed-plate girders are all box girders ; they are 4 feet wide on the top and bottom flanges, and 2 feet 4 inches high, except the one already specially mentioned, which is 5 feet wide. On the top of these girders on the Surrey piers and Middlesex piers are laid cast- iron roller paths planed, with wrought-iron turned rollers 4 inches in diameter. On the two centre piers there are no rollers, and the girders of the bridge there rest directly on the bed-plate girders. Cast-iron moulded caps, which conceal the bed-plate girders, are fixed on the tops of the cylinders. The Outside Main Girders. (Fig. ] 0.) The outside main girders of the bridge are box girders, 8 feet 6 inches high, and 3 feet 7 inches wide, with a sectional area varying with the different spans. The web-plates are f inch thick, increased to J inch thick for a length of 10 feet at each end of the girder. The transverse distance from centre to centre of the out¬ side girders is 63 feet 6 inches (Fig. 2). The Intermediate Main Girders. (Figs. 11, 12, 13, 14, 15, and 20.) The intermediate girders are single-web girders 8 feet 6 inches high, and 2 feet 2 inches wide. They are fixed 5 feet apart from centre to centre, the space between the outside girders and the next intermediate girder being 6 feet 9 inches from centre to centre. The girders for the two side openings are independent of the other spans, but those for the three centre spans are continuous over the three openings. The sectional area of the intermediate girders varies, of course, at different points, and also with the different spans, but it would occupy too much space to give in detail the different thick¬ nesses of the flanges, which are all calculated for 4 tons strain per square inch in compression, and 5 tons per square inch in tension. The web-plates are generally f inch thick, strengthened with addi¬ tional gusset-pieces and T irons at the ends. The Flooring. The flooring of the bridge is composed of wrought-iron flat plates, ^ an inch thick, riveted to the top flanges of the main girders, ex¬ tending from girder to girder, and strengthened with angle or T irons. On the Fan (Figs. 9 and 20), where the main girders are from 5 feet to 12 feet apart, cross girders are employed, in order to carry the roadway plates. These cross girders are about 1 foot 3 inches 10 charina cross railway, city terminus. deep, and are 3 feet apart from centre to centre. The floor of the bridge forms the Station Tard, and is occupied by cross roads as well as by the through lines. It was necessary, therefore, to adopt a cover¬ ing for the bridge which should be able to carry the rolling load in any direction. This purpose is fülñlled by the floor of wrought-iron flat plates ; while, at the same time, the strength of the bridge is much increased by them, both longitudinally and transversely. Upon the flooring plates asphalte, dressed to proper falls, is laid, and pipes are fixed to the cylinders to carry off the rain-water. At the piers, where rollers are employed, the flooring plates are not longitudinally connected, but are separated by an open space of about 10 inches; under this gap a cast-iron gutter for surface drainage is fixed, which is attached to the girders on one side only, and travels with them as they contract or expand. On the asphalte an average thickness of 5 inches of ashes is placed as ballast, and on this the ordinary permanent way is laid with cross sleepers. No special permanent way is thus required for the bridge, a point of considerable consequence in a position like this, where renewals are continually required, and where the number of points and crossings is unusually large. The Cross Strutting. Strutting is introduced transversely between the girders : there are three tiers of diagonal struts in each opening, and there are also tiers of horizontal struts, composed of T irons fixed between the bottom flanges. Great transverse strength is also given to the bridge by the ¿-inch wrought-iron flooring plates, which are, as has been already stated, riveted to the girders and extend completely across the bridge. The Footways, &c. (Fig. 2.) To the outside box girders ornamental cast-iron cantilevers are attached to carry the footpaths, which project from the girders and overhang the river. These castings are attached to the girders by bolts, which pass through the girders from side to side, with thimbles or distance pieces between the two webs. The footways are formed of creosoted Baltic planking 4 inches thick, upon which is laid a layer of felt, and on that asphalte. There are cast-iron parapets on each side of each footpath. That next the river is pierced, and that which separates the railway portion of the bridge from the footpaths is solid. Ornamental cast-iron pilasters are fixed over each pier, and rest on the ends of the outside girders. charing cross railway, city terminus. 11 The Signal Bridge, &c. (Figs. 1 and 2.) Over the Middlesex pier the signal bridge is fixed ; it is about 62 feet span, 11 feet 6 inches wide, and rests on four cast-iron pillars, connected together in pairs on each side by castings. One of the pillars on each side rests on the outside girder of the Fan span, and the other pillar rests on the girder of the adjoining span. As these girders rest on rollers, and are free to move with the expansion and contraction of the iron, rollers were also placed under one of the pillars supporting the signal bridge on each side. The girders of the signal bridge are wrought-iron lattice girders. They are firmly bolted to the pillars, and are strutted transversely : the cross girders are of wrought iron, and the fioor is of creosoted Baltic planking, 4 inches thick. The cast-iron parapets and pilasters of the bridge are all provided with compensation for expansion and contraction, as also are the water and gas mains. The Cost, &c., of the Bridge. The piers of the bridge, from the bottom of the cylinders to the bed-plate girder, contain in all about 2,500 tons of cast and wrought iron. The superstructure contains about 4,200 tons of wrought iron in girders, fioor plates, &c., and about 1,100 tons of ornamental castings in cantilevers, railings, and pillars, &c. The cost of the Cannon Street Bridge, including the abutments, signal bridge, and all things connected with the work, with the exception of the per¬ manent way, signals and signal apparatus, gas and water mains, amounted to £193,000. This sum gives £2 15s. as the cost per superficial foot, and £250 per lineal foot, or £50 per lineal foot per line of way including the Fan and the footpaths. The cost of the Charing Cross Bridge was estimated by Mr. Hayter (M. Inst. C.E.), in the Paper which was read before the In¬ stitution while the works were in progress, at about £180,000,^ or nearly £1 15s. per superficial foot, and £181 per lineal foot. In this estimate, however, some items of expense, such as the signal bridge, footway approaches, and additional ornamental work to the abutments and piers, were not included ; and, in order to institute a comparison between the two bridges, these must be added. If this be done, the cost of all the works at the Charing Cross Bridge, which in the parallel case of the Cannon Street Bridge are included in the above sum of £193,000, will have amounted to £202,000, or to £2 per superficial foot, and to £150 per lineal foot, or £37 lO^. per lineal foot per line of way, including the fan and the foot- ^ Vide Minutes of Proceedings Inst. C.E., vol. xxii. p. 525. 12 chaeing ckoss railway, city terminus. paths. The cost per superficial and lineal foot of the Cannon Street Bridge appears, therefore, to be considerably in excess of that of the Charing Cross Bridge ; but in the comparison it is to be remem¬ bered, first, that at Charing Cross the Company had the two brick piers of the Suspension Bridge, and part of one abutment already built ; secondly, that the floor of Charing Cross Bridge is of timber instead of wrought iron ; and, thirdly, that the weight per super¬ ficial foot on the London clay is less at the Cannon Street Bridge than at the Charing Cross Bridge. If all these circumstances be taken into account, it is believed that the comparative cost of the two bridges will not be found materially different. The great width of the Cannon Street Bridge rendered the use of cross girders unadvisable, unless a central longitudinal girder projecting above the roadway had been employed : this was clearly inadmissible, from the fact that the bridge had to be capable of carrying cross roads in all directions. The space between the necessary level of the rails, with regard to the Cannon Street Station, and the headway prescribed for the river traffic, would only admit of girders of the height above mentioned, which is about span, and therefore not of an economical height. This fact tended to increase the cost of the bridge, as compared with others, where the height of the girders is not limited by such considerations ; but nevertheless, and with these disadvantages, the cost will, it is believed, he found to com¬ pare favourably with that of other railway bridges in similar situations. THE CANNON STEEET STATION. (Plate 16.) The length of ground between the Eiver Thames and Cannon Street is 855 feet, which is occupied as follows :—the forecourt is 90 feet wide, the booking offices are 85 feet wide, and the length of the covered portion of the station south of the booking ofi&ces is 680 feet. Two of the platforms are prolonged beyond the covered portion, and extend nearly up to the signal bridge over the Middle¬ sex pier. The width of the station outside the walls is 201 feet 8 inches, and inside the walls, at the platform level, it is 187 feet. The station stands, to a great extent, on the site of the old Steel Yard ; it is almost entirely bounded, except on the ri^er side, by public thoroughfares, and is intersected by Upper Thames Street, which crosses underneath it at about half its length. The Substructure of the Station. (Figs. 16, 18, 19, and 21.) The whole of the station is built on a substructure of brick piers and arches, excepting the booking ofi&ces and the part which is over CHARING CROSS RAILWAY, CITY TERMINUS. 13 Upper Thames Street. At the crossing of this street it was neces¬ sary, in order to give the requisite headway for the street traffic,, to use wrought-iron girders, and therefore to stop the series of arches by heavy abutments. The axis of the station is not parallel to .the centre line of the bridge : this want of parallelism is made up in the pier next to the river abutment, the south face of it being at right angles to the bridge and the north face at right angles to the station. The thickness of the ordinary piers is 5 feet throughout, widened by footings at the base to 8 feet. The footings rest on concrete, the bottom of which is on the gravel overlying the Lon¬ don clay, or on the London clay itself, at depths varying from 16 feet to 30 feet below the surface of the ground. The piers are T shaped at the ends, walls being built under the ends of the main arches to relieve the weight of the station walls and roof. Openings 12 feet wide are left in the piers, so arranged as to allow tram^vays to be worked throughout the basement if necessary ; and provision has been made in the arches for an hydraulic lift to raise and lower the wagons. Excepting in the river abutment, the greatest thickness of the walls of the substructure is from 5 feet to 6 feet, open spaces or pockets being built in all the piers or abut¬ ments whose outside dimensions exceed 6 feet. The piers and abutments are almost entirely built with ordinary grey lime mortar. The span of the main arches is 28 feet 6 inches ; they are seg¬ mental, and the rise in the centre is 9 feet : those south of Upper Thames Street are built in grey lime mortar, and those north of that street, which are groined, are almost entirely built in Portland cement. The general thickness is 1 foot 10| inches, or five rings of bricks, and an additional ring is built under the station-wall, extend¬ ing inwards about 15 feet from the ends of the main arches. The 12-feet openings in the piers south of Upper Thames Street have semicircular arches 1 foot 6 inches thick, built in Portland cement below the springing of the main arch. The cross openings north of Upper Thames Street are mostly carried up through the spring¬ ing of the large arch, and are groined into it. The section of the smaller groined arch, covering the 12-feet cross opening, is a portion of an ellipse the major axis of which is vertical. By adopting this form of arch, the groin points are kept in straight lines from the centre of thé arch to the piers, which is important in brick-groining, and desirable in stone-groining (Fig. 19). The groining, which is 2 feet 3 inches thick, is built in Portland cement, and the keystone is of Bramley Fall. The groining was adopted north of Thames Street in consequence of the height of the ground, which prevented communication between the different main archways being possible by transverse arches below the springing of the large arch. With¬ out intercommunication the value of the vaults would be commer¬ cially much diminished, and they would not have been available as 14 charing cross railway, city terminus. they now are for parcels offices, stores, and railway purposes. The Author thinks that, in metropolitan works, the adapting to com¬ mercial uses those parts of railways which are only structurally necessary, and are not required to he occupied for railway purposes below the level of rails, should not be lost sight of ; and that very often a small judicious addition to the first cost will be amply re¬ paid by the increased yearly rental which, in consequence, will he commanded. In the present instance the increased cost of the groining was about £1,050, or £*042 per superficial foot ; a small sum as compared with the increased value which it has given to the basement. A series of arches sloping upwards from Upper Thames Street towards the river at an easy gradient, and then turning the reverse way with a gradient of 1 in 12, afibrds access for empty cabs to the level of the platforms at the south end of the station, in order that they may thus avoid meeting the stream of traffic passing out at the north end of the station. The whole of the arches of the substructure are covered with asphalte dressed to falls, and provided with cast-iron drain-pipes. The rails and platforms are carried across'Upper Thames Street on wrought-iron girders 2 feet 6 inches deep, the span being 37 feet : the girders are 4 feet 10 inches apart, and the width of the bridge is 202 feet. The floor of the bridge is of creosoted Baltic planking, 8 inches thick. The Station Walls. (Figs. 16, 17, and 21.) The walls are almost entirely of brickwork in mortar—the only exceptions being the arch over Upper Thames Street, and a few courses on the top of the wall, which are laid in cement. The height of the walls is 45 feet from the level of the platforms to the top of the bed-stones of the roof trusses; or about 51 feet from the top of the arches of the substructure. The ordinary piers of the walls are 18 feet 6 inches wide, and 6 feet 4J inches minimum thickness: the panels are 20 feet wide and 2 feet inches thick, these dimensions being exclusive of plinth and string-courses. The walls are carried over Upper Thames Street by a semi¬ circular arch, built in Portland cement, the span of which is 87 feet. It is built with eight 4J-inch rings of brickwork, and is 7 feet 6 inches wide. The trusses of the roof rest on Bramley Fall bed-stones 6 feet 6 inches by 5 feet, by 2 feet thick. The Eoof. (Plates 16 and 17.) The main trusses of the roof, which is somewhat similar in character to that of the Charing Cross Station, consist of segmental ribs with a tie-bar looped up. The clear span of the trusses is CHARINa CROSS RAILWAY, CITY TERMINUS. 15 190 feet inches. The rise of the rib at the centre is 60 feet, and the rise of the tie-bar is 30 feet. The truss, therefore, is 80 feet deep at the centre. The rib is 1 foot 9 inches deep, and is made like an ordinary riveted girder. The flanges are 14 inches wide and i inch thick ; the web is f inch thick, and the angle-irons are 8 inches by 8 inches by ¿ inch. The tie-bar, which is of uniform section throughout, is cylindrical, 5^^^ inches in diameter. The mode of attachment of one length of the bar to the next and to the verticals and diagonals is shown in Fig. 82. The verticals are made of two T irons bolted together back to back, with stiflening-plates to each T iron. The diagonals are plain bars 6 inches wide and J inch thick. The rib is widened out where it is seated on the walls ; an additional web-plate is riveted to the ordinary web, and the rib is, as it were, split into two parts, a casting being placed between them (Fig. 80) ; by this means the area of the end of the rib, where it rests on the wall, is increased to 4 feet by 2 feet. The principals are fixed on the eastern wall by holding-down bolts (Fig. 81) ; but on the western wall they are seated on wrought- iron collars with a peculiar saddle or bed-plate (Fig. 29). The ordinary distance from centre to centre- of the trusses is 88 feet 6 inches, being the same as the distance b^ween the centres of the piers of the substructure. In crossing Thames Street, however, the distance apart was increased to 85 feet 1J inch, in order to suit the abutments of the bridge over that street. The weight of a single truss is 4:7^ tons. The purlins are single web-girders 1 foot 8 inches deep ; their flanges are composed of two angle-irons 5 inches by 8 inches by J inch, with a f-inch web (Fig. 84). They extend from rib to rib, and rest between the flanges of the rib, to which they are attached by bolts, with holes slotted to provide for expansion and contraction. Light lattice strutting is fixed half way between the trusses, in order to prevent any sagging of the purlins. The sash- bars are of T iron, 8 inches by 8 inches by inch ; and the glass used is rough plate about J inch thick. The parts of the roof not glazed are covered partly with zinc and partly with slating. The zinc is laid with rolls on each side of the central lantern where the slope of the roof is flat, and where it is necessary for workmen employed in repairs to walk ; and again on a narrow width below the glazed portion, where a light wrought-iron and wood balcony is fixed from end to end of the roof for the use of men employed in repairs or painting. A lantern, 22 feet wide, extending nearly the whole length of the roof, is glazed on the top, and has the sides fitted with louvres, which afford means of ventilation. The gutters are of cast iron, connected together in lengths of about 67 feet, with a space between the different lengths to provide for expansion and contraction. Each length of gutter has two pipes 6 inches in diameter to carry off the rain. 16 charina cross railway, city terminus» The Gable Screen. (Plate 16, Fig. 16.) At the southern end of the roof, and resting on the two towers, is the gable screen. It consists of two wrought-iron trusses, seg¬ mental at the top, of the same radius as that of the ribs of the roof, and nearly horizontal at the bottom, the trusses being 59 feet deep in the centre. These two trusses are 11 feet apart from centre to centre, and they are connected together at numerous points, so as to form one large girder. A camber of 12 inches was given to the bottom of the trusses, in order to avoid the appear¬ ance of sagging, which is so noticeable in long horizontal lines. The glass is carried in the gable-screen in wooden frames made to fit between the iron struts and ties. The Staging for the Eoof. The timber staging for erecting the roof was movable. It ex¬ tended from wall to wall of the station, being 180 feet wide and 58 feet long in the direction of the length of the station. It con¬ tained about two hundred and fifty loads of timber, and was supported at seven points by wheels running on rails and sleepers, there being five wheels at each point. The wheels were 32 inches in diameter, and there would probably be, when the stage was^ being moved, about 7 tons on each wheel, assuming that the load was equally distributed. Two stages were used in erecting the roof, both of which were movable; the larger one, which is described above, was as high as the top of the segmental ribs, and was used for erecting the trusses : the smaller stage, being low enough to pass under the tie-bar, was used for painting, glazing, and finishing. These stagings were designed by Mr. Phillips (Assoc. Inst. C.E.), and answered their purpose admirably. The trussing of the larger stage did not commence for 28 feet above the rails ; by this means a certain amount of play, or absence of rigidity, was given to it, and the tendency which so large a staging would have, if bound together too firmly, to get jammed against the rails transversely, was counteracted. When the stage had to be moved, ropes and blocks were attached to the wheel carriages, and these were hauled in either all together or singly, as the foreman in charge directed. In addition to the two movable stages, fixed scafiblding was used for erecting the gable-screen. The Cost of the Eoof. The cost of the roof of the Cannon Street Station amounted to £49 10s. per square of 100 superficial feet of area covered, measured charina cross railway, city terminus. 17 between the walls. The cost of the roof of the Charing Cross Station was £40 per square (Plate XVII., Figs. 35 to 42). At the time the contract was taken for these roofs, iron was excep¬ tionally high, the contract price for the roofs fixed in place being £24 5s. In the above prices per square, all items of expense are included, and the adoption of this course, which is the only fair way of arriving at the cost of a completed roof, makes the price per square appear high, when compared with the prices given for other roofs, where the same mode of calculation is not followed. For instance, in the cost above given, of the two roofs under con¬ sideration, the prices of the gable principals and gable screens, the outside galleries, the repairing ladders, the expansion gear, the gutters and rain-water pipes, the roofs of the towers, and all the extra or day-work, are included. If these items of expense, which are all necessary adjuncts of a large roof, had not been included, the prices would have been reduced about £6 per square. More¬ over, it is to be borne in mind, in comparing these with other roofs, that all the materials are here of a most durable character, and that all the sash-bars are of T iron ; this latter item alone adding about £4 per square to the cost of the roof. The Arrangement of the Station. (Fig. 17.) The Cannon Street^ Station has the booking-offices, waiting- rooms, and refreshment-rooms, &c., at the north end ; the building containing them being at right angles to the lines of way. This arrangement, in the Author's opinion, is preferable, both for the public and for the railway officials, where there are a large number of platforms ; although, perhaps, the convenience of one or possibly two platforms may be better consulted by having the booking-offices at the side of the station. In the present instance, moreover, the posi¬ tion of the streets would have rendered any other plan objection¬ able. The booking and other offices are chiefiy situate on the ground- floor of the building which, above and below them, forms the City Terminus Hotel.^ Parcels offices, stores, and cellarage, &c., are provided in the basement of the station between Upper Thames Street and the basement of the hotel. Access from the rail-level to these basement offices, the floors of which are level with the adjoining streets, is given by stairs leading from the platform at the southern end of the station ; and hydraulic lifts are provided for raising and lowering the parcel-trollies. These lifts are worked by direct pressure from tanks in the towers at the southern end 1 The Hotel was erected by an independent Company, from the designs and under the superintendence of Mr. Edward M. Barry, A.R. A. 0 18 chabina cross railway, city terminus. of the station. The water, after having been used in the lifts, is discharged into tanks about 9 feet above the platform-level, and is again utilized for the water-closets and urinals, for washing car¬ riages, and for general station purposes. The Platforms, &c. There are nine lines of way in the station, of which eight lines are alongside platforms, one line being set apart for spare stock and standing room. The eastern platform is 522 feet long and 13 feet 6 inches wide at the centre. The general departure platform is 665 feet long and 19 feet wide ; the general arrival platforms are 721 feet long, and are 12 feet 6 inches wide opposite the cab road, and about 80 feet wide, on the average, beyond the cab road. The western platform is 486 feet long, and 18 feet 6 inches wide. The nature and extent of the traflSc required provision for a large number of trains being at the station at one time ; some of them carry¬ ing mails, and many a large quantity of passengers' luggage and parcels ; the duration of their stay in the station being consequently very dissimilar. In this respect the traffic differs very much from that of the Metropolitan and the Blackwall Eailways. Looking to these cir¬ cumstances, Mr. Hawkshaw determined to adopt the principle of having a line of railway on each side of the platform, instead of a plat¬ form on each side of a line. It is believed that this arrangement is the most economical in space, and, relatively to the space occupied, the most convenient in working. The side platforms, from which the heavy Greenwich, Mid-Kent, and Charing Cross, and part of the North Kent traffic is worked, are each 18 feet 6 inches wide. These two platforms accommodate satisfactorily the four lines of rails on which the above traffic is carried ; and it would not, the Author thinks, be possible to utilise the space so thoroughly by arranging the platforms on the opposite principle. Although, when a train arrives which has to leave again as soon as an engine can be attached, the passengers entering the train have to mix on the platform with those leaving it, yet it seldom or never happens that trains arrive at or depart from both sides of the same platform at one time; and the advantage, where the area of the station is limited, of throwing all the space available for platforms into two instead of into four platforms, more than compensates for the dis¬ advantage of the passengers having to pass each other. The area of the platforms which are alongside trains is 48,877 superficial feet, and the length of the trains accommodated is 4,778 lineal feet, giving about 9 superficial feet of the platform for each lineal foot of train. charing cross railway, city terminus 19 The Station-yard and Signals. The station-yard may be said to extend from the end of the platforms near the signal-bridge to the southern abutment of the bridge over the Eiver Thames, being about 600 feet in length. The five lines of way on the bridge are appropriated as follows :— That on the western side is exclusively for trains proceeding from Cannon Street to Charing Cross ; the next line is for trains ap¬ proaching Cannon Street, and is used in common by trains from London Bridge or the country, and by trains from Charing Cross ; the centre line is exclusively for trains arriving from London Bridge or the country ; the fourth line is the main down-line, and is used by trains going either to London Bridge or Charing Cross. The line on the eastern side is used for engines entering or leaving the engine depot, and for engines waiting for their trains. The short¬ ness of the station-yard, confined as it is between the ends of the platform and the sharp curves on the Surrey side, added consider¬ ably to the difiiculty of laying out the lines. The principle adopted is that every line should approach every platform without back shunting, excepting only that platform on the western side, which is to a great extent devoted to the short trafiic to and from Charing Cross. This principle has been carried out by means of about forty pairs of points, and it is probably the only arrangement which, as the trains are aU reversed here, would have allowed the trafiic to be satisfactorily worked. The signals are on Messrs. Saxby and Farmer's patent, and were erected by them under the supervision of the Engineer. The signal-box and the bridge is 42 feet long by 9 feet wide ; there are four posts, with twenty-four sema¬ phore arms, eight arms being for out trains, and sixteen for in trains. The signal-box contains sixty-seven levers, of which thirty- seven work signals, and thirty work points ; several of the point- levers working the switches at both ends cross over roads. The signals lock the points and each other, so that no contradictory signals can be given, nor can the permission for ingress to or egress from any platform be given until the points are arranged in accordance with the signal for that particular platform. The diflâculty of arranging this apparatus so as to provide for safety without impeding the working of the station was considerable, as may be gathered from the fact that there are in the locking-frame thirty-two slides and about one thousand locks. An idea may be formed of the duty which falls on this apparatus from the fact, that seven hundred and seventy-five trains have passed under the signal- bridge in a single working day (Whit-Monday), and that each train being reversed here, a fresh engine has to be attached, the engine which brought the train in having to be passed into a siding. The Author requested that the trains might be counted and timed for c 2 20 chabing oeoss eailway, city tebminus half an hour one morning, and it was found that thirty-five trains were signalled and passed in or out of the station in thirty-five minutes. Mr. Walker's electric telegraph apparatus, which works a miniature semaphore distance-signal in each box, is used for signalling the trains on the block-system between the different signalling stations. Two men are employed in the Cannon Street signal-box to work the levers, and a clerk for the telegraph instru¬ ment ; they work eight hours a day. The Cost op the Station. The cost of the works of the Cannon Street Station is given in the following Table, the cost of the Charing Cross Station (Fig. 22) being given in parallel columns for the purpose of comparison :— Cannon Street Station, Charing Cross Station, ■ Area 152,632 Superficial Feet, Area 103,672 Superficial Feet. exclusive of Fore-court. exclusive of Fore-court. Gross Cost. Cost per Gross Cost. Cost per Substructure to formution £. Superficial Foot. £. Superficial Foot. level, excluding only the north abutment of the bridge over the Eiver Thames 74,962 •491 41,422 •400 say 98. lOd. say 8s. Superstructure, including fore-court, booking-ofiBces, fittings, towers, roof, gas and water mains, &c. &c. ; excluding only the per¬ 157,262 manent way .... 1-029 111,604 1-077 say 20s. Id. say 21s. 6d. Total . • 232,224 1-520 153,026 1-477 say 30s. 5d. say 29s. 6d. about 2*92 pence about 3*37 pence per cubic foot. per cubic foot. The additional cost per superficial foot of the Cannon Street Station substructure is accounted for by the expense of crossing over Upper Thames Street. The Metropolitan District Railway passes in a tunnel under¬ neath the forecourt at Cannon Street, at a depth of about 28 feet below the surface. In order to avoid inconvenience, this short length of tunnel was built simultaneously with the works of the station, and was completed prior to the opening of the City Ter¬ minus Extension Railway, charina cross railway, city terminus. 21 THE VIADUCTS, ETC., SOUTH OF THE THAMES. Of the five lines of way on the bridge over the Eiver Thames, one, the eastern, turns off at the south abutment to the engine depot, and the remaining four lines are carried on a viaduct 48 feet wide, and about 43 feet above the foundations as far as Stoney Street signals, where a junction is formed between the three lines bending eastward to London Bridge, and three lines bending west¬ ward to Charing Cross. The viaducts are of brickwork, except where the Borough Market, York Street, and Park Street are crossed. The ordinary spans of the brickwork arches are 25 feet and 30 feet ; the minimum thickness of the piers is 4 feet, and the thickness of the arches generally is 1 foot 10 J inches. Park Street is crossed by means of wrought-iron girders 32 feet span and 3 feet 3 inches deep, covered with 7-inch creosoted planking. The Borough Market and York Street are crossed on a viaduct of five spans, consisting of wrought-iron girders from 40 feet to 50 feet average span, and 4 feet deep, resting on cast-iron hollow columns 2 feet in diameter. The columns are 24 feet high, and rest on foundations of brickwork and stone landings. The cost of the whole of the viaducts south of the Eiver Thames, exclusive of the per¬ manent way, was £32,000. The cost of the Borough Market and York Street viaduct, including abutments, was £8,775, or about £107 per yard forward for a treble line. The cost of the ordinary brickwork viaduct for three lines, 38 feet wide, and about 37 feet high from the foundations, was £39 per yard forward ; and the cost of all the viaducts, including the Borough Market and girder- bridges, was at the rate of £66 per yard of treble fine. The Engine Depot. An engine house, engine turn-table, water-tank, and coking- stages, &c., are provided on the south side of the river. The ground which was appropriated for the depot was of an awkward shape, and confined by the streets adjacent. In consequence, engines are obliged to go on to the turn-table in order to get in or out of the engine shed. The depot is carried on a basement of brick piers and arches, and the cost of the whole of the depot works, exclusive of permanent way and the turn-table, was £26,000. The Permanent Way. The permanent way consists of wrought-iron rails, weighing 75 lbs. to the yard, in cast-iron chairs weighing 34 lbs. each. The sleepers are of rectangular Baltic timber, creosoted, 9 feet long by 22 charina ckoss railway, city terminus. 10 inches by 5 inches. Eight sleepers are laid to a 20-foot rail, excepting in the station, where seven only are nsed. Check-rails are laid round the curves on the south side of the river, which are about 8 chains radius, the check-rail being raised ^ inch above the running rail. The switches and crossings are of steel throughout. The traffic on the railway imposes a severe duty on the permanent way. Taking the gross traffic, and assuming it to be equally distributed over four lines of way, it is found that about 6J millions of tons per annum pass over each line of way, of which weight about one- third consists of locomotives. The grinding action of the wheels on the curves increases the wear and tear, so that wrought-iron rails cannot be expected to last very long. Looking to the heavy traffic expected, and the difficulty of repairing the road during working hours, Mr. Hawkshaw wished to lay steel rails ; the Directors, how¬ ever, were doubtful of the expediency of so doing, and did not adopt his recommendation. The Total Cost. The total cost of the works of the City Terminus Extension Eailway was £505,336, and the cost of the works of the whole Charing Cross Eailway, including the City Terminus Extension, has been £1,160,118. The cost of the land for the whole railway, after deducting the value of surplus land, Hungerford Bridge, and pier tolls, &c., &c., was £1,900,000, making a total for land and works slightly in excess of three millions. In this sum, it is to be remembered, are included about 4J miles of railway for double line, two large bridges over the Eiver Thames, a considerable number of expensive street bridges of large spans, and two of the largest Metropolitan Termini. The cost to the South Eastern Eailway Company of the Charing Cross Eailway is no doubt a heavy burden; but, on the other hand, it must be conceded that the Company have not spent the money on any useless or valueless project. The works are all of a most durable character ; the free¬ hold property belonging to the Company under the arches of the two stations and of the viaduct, is alone of great value ; the two stations yield to none in point of situation, and the value of the traffic, which at present is not fully developed, is proved by the facfc that at the present time about fifteen millions of passengers . are annually carried on the railway. Conclusion. The Author feels, in submitting this Paper to the Institution, and in bespeaking the forbearance of the members for its defects, that he is bringing before them a subject which involves no new charina cross railway, city terminus. 23 principles of theory or practice. He trusts, however, that the de¬ scription and statistics of a work with which most of those present are more or less, as members of the public, acquainted, will not be devoid of interest, and may possibly give rise to a discussion which may redeem any shortcomings on his part. The Paper is illustrated by a series of diagrams, from which Plates 15, 16, and 17, have been compiled.^ ^ The Author has added to tlie plates whicli illustrate this Paper a plan of the Charing Cross Station Fig. 22) and the details of the Charing Cross Station Eoof (Figs. 31 to 42), in order that this Paper, when taken in conjunction with that by Mr. Hayter* (M. Inst. C.E.), may form a complete record of the whole of the Charing Cross Railway. * Vide Minutes of Proceedings, Inst. C.E., vol. xxii., p. 525. [Mr. J. W. Baeey 24 CHAßlNa CEOSS EAILWAY, OITY TEEMINUS. Mr. J. W. Baery said, that in the Paper he had given the cost of the land of the Oharing Cross Eailway, including the City Terminus Extension, at £1,900,000, and the cost of the works at £1,200,000, making together £3,100,000. The price of the land was arrived at by Mr. Eyde, the Surveyor to the Company, after deducting the sums paid by the Company for the tolls of the Hungeribrd Bridge and of the Hungerford steamboat pier, which together amounted to £140,000, as well as the price of the shares held by the South Eastern Eailway Company in the City Terminus and the Charing Cross Hotels, which together amounted to a further sum of £130,000, and after also taking credit for the surplus lands. He was anxious not to be understood as having given the total capital cost at which the Charing Cross Eailway stood in the South Eastern Eailway Company's books ; because there were other miscellaneous items of expense, such as the loss of interest during construction, rates and taxes during construction, and legal and parliamentary expenses, amounting in all to about £600,000, which would have to be added if the real cost was to be given. Adding the value of the surplus lands, the price of the tolls, the price of the shares in the two hotels, and the miscellaneous expenses, the total capital cost of the Charing Cross Eailway, including the City Terminus Hotel, amounted to £4,070,000. It was, however, fair to remark, that the tolls were still in existence, and produced a revenue ; that the Charing Cross Hotel paid a dividend of from 10 to 12 per cent. ; and that the surplus land was of value distinct from railway purposes. The freehold land possessed by the Company under the arches of the railway was also of great value, totally irrespective of the trafi&c, and was scarcely as yet developed. Mr. Eyde believed that the letting value of the land under the arches, capitalised at twenty years' purchase, would go a long way towards paying the cost of the viaduct, excluding, of course, the bridges over the roads ; and the rent of the vaults under the station would, if similarly capitalised at twenty years' purchase, probably pay the cost of the station up to the formation level. Mr. W. H. Barlow said as an idea prevailed in some quarters, that the roof of the Midland Eailway station at St. Paneras, had been more costly than other roofs of large span, he would take this opportunity of placing on record a few particulars with regard to that structure ; and alongside the figures so given he would add, for the purpose of comparison, similar details as to the roof of the Cannon Street station. Owing to the roof of the St. Paneras station springing from the ground level, instead of from the top of the walls, the weight of the roof was not borne on the walls, and, therefore, the walls were made thinner. CHARING CROSS RAILWAY, CITY TERMINUS. 25 COMPAKATIVE STATEMENT. St. Paneras Cannon St. Station. Station. ft. in. ft. in. Height of the walls above the rail-level 40 0 48 6 Average thickness of the walls above the rail-level . . 3 6 5 0 Span of the roof 240 0 188 6 Weight of principal, including spandril frame and wrought- iron foot, to the level of the floor-girders 52 tons. Weight of truss, commencing at the top of the walls . . .. 47 tons. Distance from centre to centre of principals 29 ft. 4 in. 34 ft. Area supported by one principal, measured on plan . . 7,040 sq.ft. 6,426 sq.ft. Cost of each principal £962 £1,128 Height.from the rail-level to the upper side of principal . 105 ft. 108 ft. 6 in. The reason why in one case 50 tons were procured for the same cost as 40 tons in the other was, that, in the cheaper structure, the whole of the work was of common riveted bridge-iron, and did not involve screw cutting and boring. He had not given the price per square, because that included the cost of covering, which differed in the two cases. One part of Cannon Street station was covered with Muntz's metal, and the other part with glass. In the St. Paneras station there was a tie below the level of the rails, altogether irre¬ spective of the roof, and in that way great depth had been obtained for, what he might call, the roof girder. That was an advantage which did not obtain when the roof sprang from the top of the walls. He had not included the weight of the tie, as it formed no part of the roof. When the station was decided upon, its level, being governed by circumstances over which there was no control, turned out to be 16 feet above the level of the road. The Directors and the General Manager then determined, that this space should be utilised for special purposes, and accordingly the substructure was composed of columns and girders. The result was a ready-made tie, and this was taken advantage of in designing the , roof. He believed this was the first large roof of that construction. Mr. J. T. Habrison stated that the design he sent in for the building for the Exhibition of 1851 was similar in principle. Mr. Hawkshaw,—Past President,—remarked, that a roof was now standing in Bradford, which he constructed nearly twenty years ago, springing from the platform level ; and he thought one had been erected on the Preston and Wyre Railway before that. With regard to the cost of roofs, comparisons could not be use¬ fully made, unless every particular was included. For instance, it appeared that in the roof of the St. Paneras station wooden sash- bars were to be used ; whereas in the Cannon Street station roof the sash-bars were all of iron. No doubt in that way a large roof would be obtained at a moderate cost for its size, and he thought it would be a fine work. Again, the tie-bars across the whole width of the St. Paneras station served another and useful purpose. 26 chaeing cross railway, city terminus. In respect to the cost of the Charing Cross Eailway, the Author had done what engineers were liable to do; he had denuded the capital account of several extraneous items. The cost of the work was known exactly ; it was under £1,200,000 ; and Mr. Eyde, the surveyor, by deducting the items that had been mentioned, had cut down the cost of property, which, from his point of view, might he right. Still, having to deal with what stood in the hooks of the company, Mr. Hawkshaw did not think it would be proper to let it go forth that the Charing Cross Eailway, including the Cannon Street extension, had been made for £3,000,000. It, in fact, in round numbers had cost £4,000,000. That sum, no doubt, provided for the items mentioned, and a good deal of surplus land ; indeed on some portions of the line there was room for three, and in others for four lines of way. He would not pretend to value that surplus land ; but he thought it right to state that the whole of the property, including the spare land, the pier and bridge tolls, &c., cost about £4,000,000. That exceeded the Parliamentary estimate, but that estimate was for a work of less magnitude ; in the first place, it was for two lines of way, while three had been laid, and four pro¬ vided for. The Charing Cross Bridge had been widened from two to four lines, and the Cannon Street Bridge from two to five lines of way, and the stations were twice as large as originally intended. Mr. Hood said the question was whether, in the cases both of the Cannon Street and of the St. Paneras roofs, an unnecessary outlay was not incurred to secure the advantage of one large span over the entire area. What was wanted in a station roof was good ventilation, plenty of light, and freedom from obstruction. He thought that a good roof could practically be constructed in stations of this character, which would secure the great points of simplicity, durability, and freedom from obstruction, at a much more mo¬ derate cost. He had seen nothing which led him to doubt, that the principle he had adopted in the construction of the Brighton Company's Victoria station was the correct one. There, a breadth of 240 feet was divided into two spans of 120 feet each, and the columns were put in the cab road, out of thë way of danger from the chance of a train running off the line. The roof of that station was carried by transverse trussed girders, each 120 feet span, and placed 50 feet apart, so that the cross girders were each 50 feet span. The framing was entirely of iron, covered with boarding, 1^ inch in thickness and iron*tongued, and slated, the slates being laid with a 4-inch lap ; and iron sash-bars were used throughout. By adopting the principle of trussed girders, it did not matter where the columns were placed, because the girders could always be made uniform in appearance across the lines of railway, every part of such a structure was accessible, and could be renewed at pleasure, without interfering with any other part. ohaelna cross railway, city terminus. 27 Moreover, such a station could he enlarged without pulling any¬ thing down, by additions to the sides, and the columns could be moved by strengthening the girders. The roof of the Victoria station, where there was no thrust upon the walls, which were very light, had cost, over an area exceeding 3 acres, £17 per square of 100 feet measured on plan, as compared with nearly £50 for the roof of the Cannon Street station. To that £17 per square must be added about two guineas per lineal foot, for the longitudinal columns and girders, which would bring the total average cost to something under £20 per square of 100 feet. Although the lowest tender was accepted, everything was of the best description ; the workmanship and materials were excellent, and the cost was increased by a certain amount of ornament in the details. He did not see how, with large spans, such as those at Cannon Street or at Charing Cross, the station could be widened without affecting the whole of the existing structures. He thought the Cannon Street station-roof might have been constructed at half the stated cost, if it had been divided into two spaces, and if the columns had been placed in the cab road, or on one of the platforms. He believed the arched roof belonging to the London, Chatham, and Dover Eailway Company at the Victoria station cost a little more than that of the Brighton Company's station ; although it must be borne in mind, that it was covered with zinc, that the rafters were of wood, and that it was nothing like so durable as a roof covered with boarding and slating. Mr. J. A. Longridge thought the Author of the Paper was quite right in giving the cost as an engineering work, although Mr. Hawkshaw might also be right in wishing to explain that £3,000,000 did not represent the real cost to the Company. The line had cost £3,000,000; with the other £1,000,000 engineers had nothing at all to do. Mr. E. P. Brereton remarked, that the question of the size of roofs for stations had become one of grandeur and magnificence of appearance ; but there was no actual necessity for the large spans which had recently come into fashion. Paddington station, which was spme sixteen years old, was one of the first in which large and lofty spans of iron roofs without any ties had been intro¬ duced. There the centre span was 102 feet, and there were two side roofs with spans of about 70 feet each ; and no inconvenience resulted from the supporting columns in the middle of the inter¬ mediate platforms. The Great Northern station at King's Cross had one of these roofs without a tie. It was found substantial so long as there was something more than a bare side wall to spring from; and in the case of the St, Paneras station there was, fortunately, not only a side wall, but about 20 feet of solid brick wall opposite to each rib, and he believed these 28 charma cross railway, city terminus were what would have to be principally relied upon for sup¬ port. The ties would probably not be required for any great service, and if they should ever become hot, they might rather assist in pushing out the roof. It was desirable that shareholders should not suppose that these grand and magnificent structures were altogether hopeless outlays. According to the Paper, about one- half of the. passengers using the stations under discussion were local passengers, and the receipts from them would amount to about 2^ per cent, upon the outlay. If that were so, after the first year there need not be complaints of extravagance and of money being thrown away. About thirteen thousand local passengers used those lines daily, and at four pence each, which was an average fare, this would yield 2J per cent, on the outlay. Mr. Hemans thought it would be desirable to put on record the comparative cost per square of the roofs of the stations at Cannon Street, Charing Cross, St. Paneras, Victoria, Lime Street, Liverpool,^ and New Street, Birmingham.^ Mr. J. H. Porter thought that the Birmingham station roof had cost about £30 per square. He entirely agreed that roofs of such enormous span were unnecessary, as the cost was evidently much greater as compared with that of roofs of less span. For all pur¬ poses of accommodation, and for the avoidance of all possible risks, he thought 120 feet spans ample ; and it should be considered that the weight of the principals must be taken as very nearly the squares of their spans. He had built a roof for a structure in St. Petersburg of 140 feet span, the principals of which were at in¬ tervals of 14 feet, and weighed 9 tons each. This roof was designed abroad, and he compared its weight with the weights of other structures, and amongst others the Birmingham station roof, of which the weight of the principal of 212 feet span was about 24 tons. Taking the weight of the 120 feet span at one-fourth that of the 240 feet span, it was obvious that such great spans were extravagant. A similar covering would require deeper longitudinal framing for those very great spans, which, of course, was all in favour of the lesser span. The large roofs that had been spoken of were : First, thai^f the City Terminus extension of the Charing Cross Eailway, in which the principals were of 190 feet clear span, and spaced at intervals of 331 feet. Secondly, that of the Birmingham station, in which the principals were of 212 feet span, placed at distances of 24 feet from centre to centre. And, thirdly, that of the St. Paneras station of 1 For a Description of the Iron Roof over the Railway Station, Lime Street, Liverpool," by R. Turner, vide Minutes'of Proceedings Inst. C.E., vol ix. p. 204. 2 For a " Description of the Iron Roof, in one Span, over the Joint Railway Station, New Street, Birmingham," by J. Phillips, vide Ibid., vol. xiv. p. 251. CHARINa CROSS RAILWAY, CITY TERMINUS. 29 the Midland Eailway, where the arches or ribs (not trusses) were of 240 feet span, the distance from centre to centre of the principals being 29 feet 4 inches, or say, 30 feet. As the two first- named were similar in the character of the trussing, and not very different in span, he proposed to compare the weights of their principals, and to apply the mean of those weights to a comparison with the St. Paneras roof. For this purpose they must be reduced to a common spacing and a common span. Let the spacing be that of the St. Paneras roof, or 80 feet ; and let the span be one-half that of the St. Paneras roof, or 120 feet. In the first place j^jth must be deducted from the 83J feet of the Cannon Street principal, and Jth added to the 24 feet of the Birmingham principal. In like manner a similar deduction must be made from the 47^ tons of the one, and an addition made to the 25 tons of the other. The result would be 42 • 59 tons in the one case, and 81 * 25 tons in the other ; and it would be noticed that the lighter weight was for the larger span, and mee versa. To reduce them to a common span of 120 feet— Cannon Street 190^ : 42*59 : : 120^ : 17 tons. Birmingham . 212^ : 81 * 25 : : 120^ : 10 tons. The mean of these was thus 18J tons; and that accorded very nearly with what he had found, from his own calculations and practice, to be due to a principal of that span, if spaced at 80 feet, but he would prefer principals spaced at 15 feet, and of course weighing one-half, or 6f tons. Spaced at 15 feet there would be greater stiffness in the structure generally, with great reduction in the scantling and weight of the longitudinal framing connecting the principals. The weight of the rib or arch of the St. Paneras roof was 50 tons for the span of 240 feet. Now if two spans of 120 feet had been adopted, it would have been necessary to provide one column and one girder for each bay of 80 feet, as intermediate supports, the weights of which he estimated as follows :— A column 30 feet high would weigh, say ; tons. A lattice girder 5 feet deep, of suitable stiffness, and adapted to carry the weight of 15-feet bays 3 „ Four principals, at 6f tons 27 ,, 33^ „ SO that in every bay of 80 feet there would have been a saving in weight of 16 J tons, while the saving in the weight of the longitu¬ dinal framing would have been in nearly the same proportion. Al¬ though the arches of the St. Paneras roof were continued down to the ground, there was abundance of brickwork for the support of the roofs of 120 feet span, at a height of 80 feet. Of course this argument applied with greater effect to roofs beyond 200 feet than to those within that span ; and while he ohaeing cross railway, city terminus. considered spans of 120 feet ample for all purposes of accom¬ modation, lie recognised, for example, tliat it might be more desirable to construct one span of 150 feet than two spans of 75 feet. Mr. J. W. Grover remarked that the price of the Birmingham roof was £16 per square, and that the span varied from 191 feet to 212 feet. Every principal was different throughout, which in ordi¬ nary cases would have increased the cost ; but, by a carefully-con¬ structed table, each part was varied proportionately in such a manner as to cause very little trouble. With regard to the weight to be put upon roofs, he had known instances where engineers had required a maximum of 80 lbs. to the square foot, which approached the requirements of a bridge, and 60 lbs. was common enough. He thought generally principals and covering gave a weight of about 20 lbs. to the superficial foot. The effect of wind was often much exaggerated; for if it produced a steady uniform pressure of anything like 30 lbs. or 40 lbs. to the square foot, as registered at particular spots by anemo¬ meters, the Crystal Palace ought to have been blown down long ago. The roof over the North Court of the Science and Art Department, at Kensington, covered 112 feet, both ways, without intermediate supports ; four 112-feet girders intersecting each other were used. It was a complicated roof, being constructed to meet certain archi¬ tectural features, without any ties at all, and that ran up the cost very materially. It was covered with Hartley's thick glass, a valuable covering, but one which weighed a great deal, and was costly : that roof had cost about £40 a square, and weighed 22 lbs. per superficial foot. He had found that the French engineers had gone carefully into the question of weight in connection with the first French Exhibition, and they allowed as httle as 22 lbs. per square foot for the arched roof measured on the surface, with wind and snow combined. No tie-rods were used, because, as in the St. Paneras roof, the ribs practically abutted on the ground at both ends. It was well, however, to remember, that the French engineers seldom exposed the sections to high strains. In the building in question a maximum compressive strain of 2f tons per square inch seemed to have been adopted for the wrought-iron members. He believed that in the Birmingham station-roof the principals cost about the same as the covering, £8 a square being put down for the principals, and £8 for the covering. He had been told that the roof of the station at Worcester, where the spans were 80 feet, only cost about £12 a square; and there had been many roofs constructed of 60 feet span, which he believed was the cheapest form, for £10 or £12 a square. Mr. Hood said that, when constructing the Victoria Station roof, he had been informed by the Engineer of the Great Western Bail- charma cross railway, city terminus 31 way, that the cost of the Paddington roof was £19 a square, exclu¬ sive of columns and girders. Mr. E. Kyde stated that the actual money paid for land for the Charing Cross main line and station was about £1,862,000 ; that was to say, a sum of £560,000 was paid for land in Middlesex, and £802,000 for land in Surrey ; but the former amount included the purchase money of the Charing Cross foot-bridge, which thé Company were compelled to buy, although they did not want it. The bridge, which was earning upwards of £4,000 a year, was acquired at twenty years' purchase. During the construction of the station the tolls were not continued the same ; but in future the bridge would pro¬ bably earn 5 per cent, upon its cost. That, therefore, was a distinct property, and the two properties should not be confused with each other. It was a question whether railways in London would or would not pay, and to ascertain this, that which belonged to the railway must be separated from that which did not. The same observation applied to the Charing Cross pier dues, which were stiU received by the Company, except in so far as the Metropolitan Board of Works had interfered with them, and in that instance the Board had paid compensation. The £65,000 put down for shares in the Charing Cross Hotel, which shares Lord Kedesdale compelled the Company to hold, represented an expenditure for land which would not have been required for the railway, including that occu¬ pied exclusively by the Hotel Company in Yilliers Street. All these separate items of expenditure being deducted, left the cost of the land for the Charing Cross line proper and the Charing Cross station at £1,000,000, including land for a fourth line of way, and for a station at Waterloo, which the Company were shortly going to build. On the question of St. Thomas's Hospital, he only took credit for £150,000, which was the sum in cash for which the Company sold the surplus land ; but they had a second mortgage on that pro¬ perty for an additional sum of £20,000. In regard to Cannon Street, the cost had been correctly stated. One feature of railways in London was the comparative advantage and cost of underground and overground railways. He could demonstrate that railways above ground were the cheapest, pro¬ vided the arches were built so that they might be advantageously let ; and the Author was quite right in saying, that the arches would pay 5 per cent, on the cost of construction, assuming the cost of railway arches to have been correctly stated. The arches under Cannon Street station would not, in his judgment, realise the rents that had been anticipated, but they would realise sufficient to pay interest on the cost of construction, as those along the line of railway had done already ; that was a result which could not be obtained from underground railways. Mr. J. W. Bazalgette thought that the statement that the 32 chaeina ceoss eailway, city teeminus arches of railways would pay 5 per cent, upon the outlay was too general and somewhat doubtful. This statement, he believed, could have reference to a few exceptional cases only, for he had found that the bulk of the arches carrying overground Metropolitan railways were not occupied : therefore the argument in favour of Metropolitan overground railways as against underground rail¬ ways, based upon such an assumption, .was hardly satisfactory. Perhaps that opinion could be supported by a more definite statement of the facts, which would tend to justify such a con¬ clusion. The comparison of the advantages and cost of the overground and underground railways within the Metropolis was so important a subject, that such information would have a pro¬ minent bearing in the designing of future Metropolitan railways ; and certainly without a large return, in the shape of rent, for the arches, to meet the cost of the purchase of property required for overground railways, it would be found that in London those con¬ structed underground were much less costly than those constructed on ' arches, although the works involved in the former were fi:e- quently of a difficult and costly character. Mr. T. E. Haeeison, Vice-President, thought that in comparing a large span with two small ones, the cost of the columns and the cross-girders ought to be included. In the North of England, where Directors looked not a little to the pounds, shillings, and pence, if it were proposed to make a span of 240 feet the inquiry would at once be made. Was there a necessity for that, and what would be the cost as compared with two spans or even three spans ? He had been governed entirely by considerations of cost in the cases in which he had introduced smaller spans ; and he knew from experience that roofs varying in span, from 80 feet up to 120 feet, with the columns, cost from £18 to £20 a square as a maximum. He had never found any difficulty in arranging a station with a divided roof. Where Directors looked upon the question of cost as an im¬ portant element, he, as their Engineer, had been so governed in making his designs. Mr. Phipps observed that the area of foundation-bearing surface was so much greater in the Cannon Street Bridge than in the Charing Cross Bridge, as to give a pressure of 6 tons on the square foot only in the former case, while in the latter it came up to 8 tons. Mr. Hawkshaw said the difference of construction rendered more columns necessary in the Cannon Street Bridge, as the longi¬ tudinal girders required to be supported across the whole breadth of the bridge. At Charing Cross side girders carrying transverse girders were used, and two- columns were sufficient. At the Cannon Street Bridge the whole of the main girders ran longitudinally to the bridge. Eoofs could be erected at various prices, even when of. charim cross railway, city terminus. 33 the same span ; but they might he constructed of such light or undurable materials, that in a short time they would be oxidized and rotted away, as had been the case in some roofs. There was no doubt, also, that the smaller the span the cheaper would be the roof : but he totally dissented from the opinion, that there was no use in getting rid of columns, for he believed that the value of having no columns might far exceed the additional cost of the roof. Take the Tithe Barn station at Liverpool, which was one of the earliest of the large stations he constructed ; no columns were used there, but the whole width of the station was roofed over in one span, and as the traffic increased, the lines and platforms were moved and modified, so as to enable treble the amount of traffic to be carried on. That would have been impossible if the'roof had been built with columns ; and he had no hesitation in saying, that the Company had been repaid the increased cost of making the roof of that station in one span many times over. The question had been fully considered in reference to the Charing Cross and the Cannon Street stations, and he came to the conclusion that intermediate columns ought not to be used. He believed the value of those stations would have been greatly di¬ minished, if they had been divided into bays with columns, for the sake of reducing the price of the roof. He had generally allowed, in addition to the weight of the trusses, 40 lbs. a square foot for the covering and pressure of the wind. Mr. J. W. Barry, in reply upon the discussion, said that he entirely concurred in the observations as to the inadvisability of employing columns between the platforms or lines. He thought any one who, after considering the great value of the space enclosed within the walls of those two stations and the enormous cost of the land, looked at the plans, would see at once, from the way in which the platforms were necessarily disposed, the great difficulty there would be in putting columns in positions which would not be objectionable. It was difficult to come to a sound conclusion regarding the prices of roofs, square for square, because the mode of construction, and consequently the cost, varied considerably in different positions and under different circumstances. For instance, in the St. Paneras roof, wooden sash- bars were employed, while at Cannon. Street and Charing Cross the sash-bars were of iron. Any one who had been present at the recent fire at Charing Cross station must have owned that the. iron sash-bars were preferable ; and certainly, in this instance at least, the iron sash-bars might be taken to have well repaid the cost of their adoption. At Charing Cross and Cannon Street stations the position of the streets prevented the employment of any side abutments to sustain the thrust of the roofs, which there¬ fore had to be self-contained. The price of iron was comparatively high at the time the roofs were made ; and moreover, as was ex- D 34 chakina cross railway, city terminus pressly stated in the Paper, the cost given was the actual cost of the work as executed, and included every possible item of charge. He thought the proper object of Engineers was to make useful and commodious structures, taking advantage to the utmost of the land at their disposal, which, in situations similar to those under dis¬ cussion, had been acquired at such great cost. So far as Cannon Street and Charing Cross were concerned, these objects, he thought, had been carried out. It only remained to say, that when Mr. Eyde estimated that the rent of the arches, capitalised at twenty years' purchase, would pay for the cost of the viaduct, his remarks applied to railways which passed through crowded neighbourhoods, and not to railways like the Greenwich Eailway, which for a long distance traversed fields and market gardens. Mr. Greoory—President—observed that any engineer who had inspected the Charing Cross Eailway and the City Terminus Exten¬ sion of that line must have been struck with the admirable execu¬ tion of the works. Undertakings of such magnitude and such character ought to remain on record ; and he much wished that engineers generally would emulate Mr. Hawkshaw and his assist¬ ants, by giving Papers descriptive of the other Metropolitan lines. Accounts of the works of the underground railways of London, from their Past President, Mr. Fowler, or some of the gentlemen connected with him, would be especially appreciated. Upon such Papers there would be an opportunity of discussing the question suggested by Mr, Eyde, as to the comparative merits and cost of underground and overground railways. A good deal might be said on both sides. It had often been urged, with a certain amount of primâ facie good reason, that by making them to ^ great extent under roads, underground railways were much cheaper ; hut it was one of those subjects which ought to be ex¬ hausted not merely by speculation, but by practical illustration. He was glad that the Author had adopted the suggestion to give the exact cost, and not the analysed and reduced cost; because all matters which were part and parcel of the cost of a railway ought to be considered by the engineer, particularly looking to the important element of the profit of a work. He had been pleased to hear that the local traffic alone between Charing Cross and Cannon Street produced 2J per cent, profit on the outlay ; but he was afraid, if all the extension railways running into the Metro¬ polis were looked at, they would not be found generally to have been so successful. One of the questions which engineers were hound to consider was the financial results of their various opera¬ tions. It had been observed, in reference to a statement as to the cheap cost of the Birmingham roof, that at the time that roof was CHARING CROSS RAILWAY, CITY TERMINUS. 35 made, the price of iron was very low, and it had been stated that the price now was still lower ; but it should be remembered that when the Cannon Street and the Charing Cross stations were built the price of iron was high. The price of ironwork was given in the Paper as £25 a ton when the Cannon Street roof was constructed ; and, in making comparisons of roofs of different styles of construc¬ tion, the important element of the cost of the raw material ought not to be forgotten. LONDON: PRÜNTED BY WILLIAM CLOWES AND SONS, STAMFORD STREKT AND CHARING CROSS. lofyíRRINCOOi M STATION ^C/RCH LEABl /CANNON' ^'^TATIO "^TACKFRIAffS ST< ftFAl-C STAT."/ BLACKFRIAR5 STATION^ /TWATERLOW y STATION^ LONDON BRfOCE STATION CHARLflirTE& ul y SOUTH/y^ESTERI^ WATER LO(»/CTAT10N_^^ i-ktOR" BOROr ROAD STATION —B^SS^ fELEPHANt^ 'AND CASTLE STATION. RI CK LATER; V ARMS / PEfflTEN MAP OF CHARING CROSS RAILWAY & CANNON STREET EXTENSION. q_ Jg ijî -t» 7jJñ'¿e. CANNON STREET EXTENSION SIGNAL BOX ai i:®M tcai^ÉTtoii Trinity Miffhy IVa^ier' Iri^iéy JjQ-w '[Vbcier ELEVATION OF BRIDGE WITH SECTIONS OF CYUNDERS ■ AND BED OF RIVER. j£ 1 I I I ^ 1 3 1 1 tAngOtlron 3^ 3V/z ^Jron 4"x4-'k^/8 .AI. CO vers 3'/z-x3','z A/s [ro7^ J 4»" •ys liai e SECTION OF BED PLATE GIRDER rig: 8. 5',£" Diaphragrrc Plate QP' QAixtjijc.Iron.ß'x3''xi^"^ Ulcsc. letter-,'^ i^cIer" to S act I Ol 1.9 of Cyh'ji dAi" J?la tA9. SECTION OF BED PLATE GIRDER, MIDDLESEX PIER .1 covcm 3,'/s">:3/z'x^/^" ^AngtelrojL 6"x 3"X^/3 CROSS GIRDERS OF FAN 2¿.2J' INSIDE GIRDER; J25 feet Spoil. 3:. 73 OUTSIDE GIRDER /95 fceP SpoLn. CONTINUOUS GIRDER OVER THREE CENTRE OPENINGS. S Si wins- of J3t> fccr crich > MAIN GIRDER OF FAN iro/ S; > n.ii SECTIONS OF CYLINDER PLATES QUARTER PLAN OF CYLINDERS SECTION OF TAPER RINi PLATE 15. Teil vit- !>S^ Low Ulalcr ^ ^ Ci"- .* o o » -»'S-Vo -CRAVELí LONDON CLAY. 't/'lf If'!/ WW CROSS SECTION OF BRIDCE- ( g ^ 32 IE .-^oFeet. J. W. BARKY, REL^ of The HhstitattoiL of Ciwl Exi^meers: Vol XXKIL. Session 1867-68. KELL, BRO? LTTH?s CASTLE ST HOLBOKN". FLATE m © l}il Ä IK i IM © ©^©SS I^AllLWAY. CANNON STREET EXTENSION. J.W. BARRY, DEW HALF ELEVATION AND HALF SECtiON, CANNON Scalen: 30FeeJ:y=lIrhch. Y........4^ y F ᣠ1 L STREET STATION. looFe^t'. Minu1'3S o£ Froceedin^s et The Institution o£ P-, .'mi Enéineers. Vol XXV Ii, )ñsBior\ ±867_68, KELL, BRD? LITH*? CASTLE ST HOLE.OBIT P*ncEi.s oe CLOAH ROOM HORSES, CARRtAceS HORS ra, CARRIAGES CHARtNC CROSS PLATFORM PLAN, sh^ywùicf a^r'Oi^-gejnerfL' of Gi-rdcrs of mirL- oii^ ordin oLOA' Span oí' Caj^tnon Streot Bn-dflO. 'h WauUe*' GENERAL PLAN OF CANNON STREET STATION, AT RAIL LEVEL ■ ' ■ • C R A VFi ' OR LÖ ROON LONGITUDINAL SECTION, CANNON STREET STATION GROINING Sea] o,. iOFeet- STAIRS TO FOOTWAY OF BRIOr.c Scjcú>e<; 30 Feet _ J InrJt GREENWICH A CANNON S7 .BOOFiKO orrii L*CARRIAGE D. I SECOND I CLASS WAIT? AO« UDIESl VâlTIAG i ROO«. î GARRI« PLAN OF BASEMENT, CANNON STREET STATION APPROACH TO FOOTSRIDCE GENERAL PLAN OF CHARING CROSS STATION, AT RAIL LEVEL £i wFeet ñMLWAY, CANNON STREET EXTENSION ^wwww^ -)"rivntf ^^^CONNECTION OF GLAZING TO ZINC. RIDCE RAIL TOP OF LOUVRE STANDARD PiL flirt. Pllflill SYz X 3\Vz SYÜ X 3>/2X 3^" %^4-Y xYx i/s' OF MAIN RIB. COUPLING táZ//////////, LOUVRE RAIL Y CONNECTION OF SLATING TO CLAZIN Elevation SECTION OF MAIN RIB (ion with Yurliiix aV lowin Elevation f. If)" ^ Klevjil ion YY//////JS'/Simm SADDLE FOR FREE END IVfjé Wo il. SECTION OF MAIN RIB, showing jzuLCtiotr ivit.h FurLins á Plan. COUPLING OF TIE-ROD FOOT OF PRINCIPAL END VIEW OF PRINCIPAL .Jitylipfj- Ëmm West Wn.i Lrfw rfn FIXED END OF PRINCIPAL ROLLER END OF PRINCIPAL END VIEW OF PRINCIPAL Fin'oil, End., \'LY' ^ 'I Si ci.iih)p^ Plan. CHARING CROSS STATION ROOF. Plan. CANNON STREET STATION ROOF. Scale SrrlY^f 29. 30, 31, 32, 33, 37, 38. 39, K). I LP J.W. BAB.RY, PELT Minutes of Proceedings cf Phe Institution oí' Civil Enéineers. CLLTI. Ses gion L867_68. wer., 3R( IJTHV? rvoriv: fi W V3Í. 3 5556 042 158642