Forth The Forth Bridge, designed by Mr John Fowler and Mr Benjamin Bridge. Baker, is the largest and most remarkable railway bridge in the world. One of its spans is shown in elevation and plan in fig. 20. The bridge consists of 2 spans of 1700 feet each, 2 of 675 each, 15 of 168 each, and 5 of 25 each. Including the width of the piers, there is almost exactly 1 mile of main spans and half a mile of approaches by viaducts, making together about 1 miles of total length. The clear headway under the centre of the bridge is 150 feet above the level of high water, and the highest part of the bridge is 361 above the same level. Each of the three main piers consists of a group of four cylindrical piers of masonry and concrete, 49 feet in diameter at the top and from 60 to 70 in diameter at the bottom. The deepest pier is about 70 feet below low water, and the rise of the tide is 18 feet at ordinary spring tides. In the piers there are about 120,000 cubic yards of masonry and in the superstructure 44,500 tons of steel. The contract was let for the sum of £1,600,000, being at the rate of £645 per lineal yard. An impression of the magnitude of the bridge is derived from a comparison with the largest railway bridge in England, the Britannia Bridge, which has a span of 465 feet, the ratio of which to that of the Forth Bridge-1700 feet-is as 1 to 3.65. The site of the Forth Bridge is at Queensferry. At this place the Firth of Forth is divided by the island of Inchgarvie into two channels, which, being as much as 200 feet in depth, precluded the construction of intermediate piers. Hence the adoption of two large spans of 1700 feet each, between which the central pier is founded on the island midway across. The bridge is composed of three double lattice-work cantilevers, like scale-beams, 1360 feet in length, poised on three substructures, and connected at their extremities by ordinary girders 350 feet long, which complete the main spans. The bridge is taper in plan, varying from a width of 120 feet-the distance apart of the lower members of the cantilevers at the piers to a minimum of 31 at the ends, in order to confer a degree of stiffness laterally, for resisting irregular stresses, wind-pressure in particular. columns above the piers, forming the basis of the cantilevers, are 12 feet in diameter. The lower booms, as well as the struts of the cantilevers, being the members in compression, are circular in cross section, this form of section having been selected as the most The lower boom is at effective for resisting compressive stress. the piers 12 feet in diameter, constructed of plates 14 inches in thickness. The size is gradually reduced towards the ends, where the diameter is 5 feet, made of plates three-eighths of an inch in thickness. Correspondingly the upper member of each cantilever is a tapering box-lattice girder, rectangular in section, 12 feet deep by 10 wide at the piers, and 5 feet by 3 at the ends. The central girders are 32 feet apart. The wind-pressure is assumed for calculation at a maximum of 56 lb per superficial foot. It is calculated that the maximum possible stress on any member of the bridge is at the rate of 7 tons per square inch of section. The required ultimate strength of steel under compression is from 34 to 37 tons Between per square inch, and under tension from 30 to 33 tons.

The

the two main girders the double line of way is to be carried on an

internal viaduct (see smaller figure in fig. 20), supported by trestles and cross girders. The way will consist of heavy bridge rails, Brunel section, laid on longitudinal sleepers bedded in four steel troughs, into which the wheels will drop in case of derailment, and then run on the sleepers.

Railway Stations.-Railway stations are either "terminal" or Stations. "intermediate." A terminal station embraces (1) the passenger station; (2) the goods station; (3) the locomotive, carriage, and waggon depôts, where the engines and the carrying stock are kept, cleaned, examined, and repaired. At many intermediate stations the same arrangements, on a smaller scale, are made; in all of them there is at least accommodation for the passenger and the goods traffic. The stations for passengers and goods are generally in different and sometimes in distant positions, the place selected for each being that which is most convenient for the traffic. The passenger station abuts on the main line, or, at termini, forms the natural terminus, at a place as near as can conveniently be obtained to the centre of the population which constitutes the passenger traffic. The goods station is approached by a siding or fork set off from the main line at a point short of the passenger station. Terminal branches of the railways-where, for example, there is a sharp incline are sometimes worked by stationary engines and ropes to the point where the locomotive joins the train. The locomotive station is placed wherever the ground may most conveniently be obtained, at or near to the terminus; in some cases it is found at a distance of 3 or 4 miles. An abundant supply of good water and ample means of drainage are important at stations. There should be ample area of land to admit of the greatest possible extension of accommodation, and the erection of buildings on land adjacent to the station grounds should be discouraged. Companies have been compelled to repurchase at greatly advanced cost land originally disposed of by them as "surplus," and generally with a view to building operations. When this course is adopted prudent managers should take care to secure in the conveyance power to repurchase the freehold at original prices, with allowance for outlay in building or otherwise, by valuation.

In laying out the approaches and station-yard of passenger Arrangestations ample width and space should be provided, with well- ment of defined means of ingress and egress to facilitate the circulation of termini. vehicles, and the setting-down pavement should be as long as possible, to admit of several carriages discharging passengers and luggage at the same time. The pavement should be wide and sheltered from the weather by a roof, overhanging beyond the kerb, or spanning the roadway, but in all cases free from columns. The position of the main buildings relative to the direction of the lines of rails is the distinguishing feature in terminal stations. When space permits, the usual course is to place them on the departure side parallel to the platform, but they are frequently placed at the end of the station at right angles to the rails and platforms. Or these two systems are combined in a third arrangement, in which the offices are placed in a fork, between two or more series of lines and platforms. Of the metropolitan termini, the Great Northern

passenger station, the Great Western, and the South-Western stations are examples of the first class; the London Bridge, Cannon Street, Charing Cross, and Victoria stations (comprising the SouthEastern and the Brighton lines), and the Great Eastern and the Fenchurch Street stations (comprising the North London, Blackwall, North Woolwich, and Tilbury lines), are examples of the second class; and the London and North-Western station is an example of the third class. The first and usual class of stations commands the greatest length of setting-down pavement, ample space for booking and other offices, waiting-rooms, &c., and the shortest average distance for passengers and luggage from the offices to the outgoing trains. Nevertheless, where the traffic is various, involving the despatch of numerous trains to different points in quick succession, and necessarily with perfect regularity, the second system is the best. But where the frontage is limited, and where trains start at some distance from the entrance, there is inconvenience in the movement of luggage over a crowded platform. The third plan is probably the least commodious of the three; but it has the advantage of affording two arrival platforms, with carriage-roads alongside, the others having but one so situated. In all the classes, it may be observed, transverse lines are inserted with turn-tables, to place all the lines in compact communication for turning on or off spare carriages, loaded horse-boxes, or carriagetrucks. Independently of the turn-tables, the lines of rail are connected by switches or points converging towards the two main lines of rail, outgoing and incoming; and thus the assortment and marshalling of trains may be effected by horse or engine power independently of the turn-tables. Each plan of station comprises one or more large turn-tables for reversing the engine with its tender together.

The correct arrangement and appropriation of the several lines of railway in a terminal station materially affect the economical and efficient working of the traffic. It is essential that every traffic line, both in and out, should be provided with one or more spare sidings, in addition to those set apart for the break-vans, horse-boxes, and carriage-trucks, and for the locomotive department. All these lines should communicate with each other by means of points and crossings, to allow of shunting with engine-power, and to reduce to the lowest limits the number of turn-tables or their substitutes. Curves ought never to have a radius of less than 800 feet.

The practice with regard to the height of platforms above the rails has varied considerably, the tendency being to raise them much higher than was usual at first; 3 feet may be stated as the limit in this respect. Too much attention cannot be given to the necessity for obtaining the greatest possible width of platform. Where the platform is used on one side only, the width ought never to be less than 20 feet; and when both sides are required 30, or even 40, should be allowed. The best mode of constructing the platform is undoubtedly with stone slabs laid hollow upon longitudinal walls, so as to admit of carrying beneath it the water and gas pipes, telegraph or signal wires, and the general drainage, with free access to each. Cutting out for turn-tables and openings for cross lines of rails are frequently inevitable difficulties, which have given rise to various ingenious contrivances, as shifting-stages, drawbridges, &c. By far the best substitute for the turn-table yet introduced is the traverser. If well made and carefully worked and attended to, the shifting of carriages from line to line can be performed without extra manual labour or interference either with the rails or the platforms. The other objection is best met by the use of easy inclines, with crossings on the rail-level. Where the platforms do not exceed 2 feet in height and the surface is smooth, gradients of 1 in 10 are not too steep for luggage-barrows, nor are they dangerous in a crowd.

The earlier terminal railway stations were designed either with intermediate columns supporting the roof or with brick walls, varying in number of spans from two to five or six. It often happens that in the course of a few years such stations have to be remodelled to meet the constantly increasing traffic; and great difficulties are Occasionally met with in the rearrangement of platforms which are wasted where lines of rails have been laid, whilst rails are wasted where platforms are placed, and where columns interfere. To allow engines and carriages to pass from one line of rails to another at the shortest possible intervals it becomes necessary to have diagonal crossings from one part of the station to another in many directions, while at the same time the free movements of passengers and luggage on the platforms must not be impeded. Thus there arose a system, originated, it is believed, in the great Continental termini, of constructing roofs in two spans, one covering the up lines of rails and the other the down lines. King's Cross passenger station is an example of this kind. The principle of wide spans for the roofs of railway stations, clear of intermediate walls or columns, was adopted in England probably for the first time in 1848-49, in covering Lime Street station, Liverpool, on the London and North-Western Railway, by one span of 1531 feet. The extreme length of the roof was 374 feet. The new Lime Street station, it may be added, is covered by a roof of one span of 212 feet. Tythebarn Street station, Liverpool, on the Lancashire and

Yorkshire Railway, is covered by a roof in one span of 136 feet; there, as the traffic increased, the lines and platforms were changed so as to admit of treble the quantity of traffic being conducted, which would have been impossible if the roof had been built with sectional spans and columns. It is averred that the railway company has been repaid the excessive cost of the single-span roof many times over in economy of working. The next single-span roof on a large scale appears to have been that of 212 feet covering the New Street station, Birmingham, in which five lines of way, belonging to different companies-the London and North-Western and others meet and concentrate passenger and goods traffic of every description. The roof was 840 feet in length, with trusses or principals placed at intervals of 24 feet. The principal consists of one arched plate-iron girder 15 inches deep, having a rise of 45 feet at the centre. The ends of the arch are tied by a round tiebar 4 inches in diameter, from which the arch is strutted at intervals. This is said to cover the largest area of any station in England. The Cannon Street station of the Charing Cross Railway is the Caunou terminus of the City extension of that line, giving direct access to Street the City of London for the South-Eastern Railway, and linking the station. Charing Cross station at the west end with the City. During the year 1867-the first year the extension was open for traffic-about 8 million passengers used the Cannon Street station, of which nearly one-half were local passengers booked between Cannon Street and Charing Cross. The length of ground between the river Thames and Cannon Street is 855 feet, of which the fore-court occupies 90, the booking-offices 85, and the shed or covered portion of the station reaching to the river 680. The station is 201 feet 8 inches wide outside the walls and 187 feet inside. The whole of the station is built on a substructure of brick piers and arches, excepting the booking-offices and the part which is over Upper Thames Street. The ordinary piers are 5 feet thick with footings 8 feet wide, resting on a bed of concrete 10 feet in thickness, and the whole of the under structure is made available for storage and other purposes. The rails and platforms are carried across Upper Thames Street on wrought-iron girders 2 feet deep to 37 feet of span. The floor of this bridge is of creasoted Baltic planking 8 inches thick. The walls of the station are of brick-work, 45 feet high above the level of the platform. They are built in piers 6 feet 4 inches thick and panels 2 feet 7 inches thick. The roof is of ono clear span of 190 feet 4 inches circular, having a rise or versed sine of 60 feet at the centre, composed of ribs constructed of plateiron and angle-iron, and, like ordinary girders, 21 inches deep, each foot of each rib being tied by a tie-bar of round wrought-iron 5 inches in diameter. The tie-bar rises 30 feet and the depth of the truss at the centre is 30 feet. One end or foot of the rib is fixed to the supporting wall and the other end is placed on rollers, by the aid of which the principal or truss is free to expand or to contract according to the variations of temperature. The trusses are placed at from 33 to 35 feet apart. The booking-offices, waiting-rooms, &c., are at the end of the station on the ground floor of the building, which above and below them forms the City Terminus Hotel. Parcels offices, stores, cellarage, &c., are provided in the basement, with hydraulic lifts worked by direct pressure from tanks in the towers at the south end. The used water is discharged into tanks about 9 feet above the level of the platform, whence it is again utilized for the general purposes of the station. There are nine lines of way in the station, of which eight run alongside five platforms, and one line is space for stock and for standing-room. The two outer platforms are employed for the short traffic to Greenwich and Mid-Kent and to Charing Cross, 13 feet wide by 522 and 486 feet long respectively. The general departure platform is 665 feet long and 19 wide; and the two general arrival platforms, one on each side of the cab road, are 721 feet long by 12 wide. On this system there are two lines of rail to each platform, reckoning the general arrival platforms as one; accommodation is thus found for 4788 lineal feet of trains. These nine lines of way converge and merge in five lines of way over the bridge for a length of about 600 feet, constituting the station-yard. The first line, on the western or up-stream side, is exclusively for trains proceeding from Cannon Street to Charing Cross; the second line is for trains approaching Cannon Street, whether from London Bridge, the country, or Charing Cross; the centre line is exclusively for trains from London Bridge or the country; the fourth is the main down line; the fifth, or east line, is for engines going to or from the engine depôt at the far end of the bridge, or for engines waiting for their trains. The movements of the trains are regulated from the signal-bridge, which crosses the converged lines of way at a distance of about 140 feet from the south end of the station, by means of about forty pairs of points, with twenty-four semaphore arms, eight of which are for trains outward and sixteen for trains inward. The signal-box on the bridge is 42 feet long and 9 wide, and contains sixty-seven levers, by thirty-seven of which signals on Saxby and Farmer's system are worked, and by thirty the points are worked. Several of the point-levers work the switches at both ends of cross-over lines. The signals lock the points and each other, so that no contradictory signals can be

given; nor can ingress to or egress from a platform be given until the points are set accordingly. There are in the locking frame thirty-two slides and about a thousand locks, and an idea of the duty that falls on this apparatus may be formed from the fact that 775 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 to it, the superseded engine being passed into a siding. In the course of thirty-five minutes one morning thirty-five trains were signalled and passed in or out of the station. The duty of signalling is performed by two men. The cost of the works of the Cannon Street station, with the cost for Charing Cross station for comparison, is shown in Table XXV. (below). The substructure is reckoned to the formationlevel, inclusive of the public footway under Charing Cross station and the public roadway under Cannon Street station, but exclusive of the river abutment of the bridge. The superstructure includes the fore-court, booking-offices, fittings, towers, roof, gas and water mains, &c., excluding the permanent way.

The total cost of the works of the whole Charing Cross Railway, from London Bridge station to Cannon Street and Charing Cross, with the terminal stations, was £1,160,118. The cost of the land for the whole railway, after deducting the value of surplus land, Hungerford Bridge, pier tolls, &c., was £1,900,000, making a total for land and works of over £3,000,000. For this sum there are 4 miles of railway for double line, the cost being at the rate of £680,000 per mile. The works include two large bridges over the river Thames, a number of expensive bridges over streets, viaducts, and two large metropolitan termini. The cost for land at Cannon Street station was at the rate of £3, 15s. 7d. per square foot, and that at Charing Cross station was £2, 18s. 5d.

The

St Pancras passenger station of the Midland Railway is the most recently constructed metropolitan terminus. The approach to the land on which the station is built was crossed by the Regent's Canal, and in order to secure good gradients and suitable levels for metropolitan suburban stations the main passenger line is carried over the canal; and, as a result, the level of St Pancras station is from 12 to 17 feet higher than that of the adjoining roads. St Pancras branch, on the contrary, for effecting a junction with the Metropolitan Railway, leaving the main line some distance from the terminus, descends through a tunnel beneath the Regent's Canal and the passenger station, as well as under a considerable length of the main line. The height of the rails above the groundlevel admitted of the construction of a lower floor with direct access to the streets, built and arranged for Burton beer traffic. The floor of the station is supported on girders and columns extending from side to side and acting as a tie for the roof girders, which start from the ground-level and form the roof as a single arch. The ribs or girders forming the roof are laid to a clear span of 240 feet; the walls built between the ribs are 245 feet apart. The clear height of the ribs above the level of the platforms is 96 feet at the centre. The length of the station is 689 feet 4 inches. The lower floor contains 720 cast-iron columns set on brick piers, and 49 rows of principal girders across the station, with 15 rows longitudinally. Upon these intermediate girders are carried, and the whole is covered in with Mallett's buckled plates. The cost of the ironwork of the floor was £57,000, being at the rate of £3, 0s. 6d. per square yard. The roof girders, twenty-five in number, are placed at intervals of 29 feet 4 inches, except at the outer end, where the last two girders are only 14 feet 8 inches apart. The cost of the roof, including covering, with two gables and screens, amounted to £69,365, being at the rate of £40, 18s. per square of 100 square feet or 10 feet If there had not been any floor-girders to act as roof-ties, square. the extra cost for ties at the level of the floor would have been about £1 per square.

Table XXVI. gives the spans and areas covered by the roofs of some of the principal London passenger termini :—

The

The goods and mineral station at King's Cross may be selected as King's an example of such stations. It comprises coal depôts and wharves, Cross potato-stores, engine-sheds, repairing sheds, stores, stables, and all goods the necessary offices, buildings, and appliances required for the station. goods and mineral traffic of the company. Twelve lines of rail run into the goods-shed, with a platform at each side for the receipt and despatch of goods. On the outer side of the rails, within the building, space is reserved for the vans engaged in collecting and distributing the goods. The outer line of rails at the east side of the platform is used for unloading the waggons with the inward goods, and that on the west side for loading the outward goods. The inner lines nearest to these are used for the arrival of goods trains, for empty waggons, and for making up trains for departure. The waggons, after being unloaded, are taken by means of turntables and cross-roads to the departure side of the station, where the business of loading and despatching them is carried on. platforms have each two rows of hydraulic cranes, of 1 and 2 tons lifting power alternately. The receiving offices are on the platforms, but the general offices are adjacent to the main building. The stables are under the platform; the granary is at the south end of the goods-shed, through which it is approached by two lines running through the middle of the shed,-two other lines, one on each side of them, being reserved for full waggons. When emptied, the waggons are removed by two lines which run one on each outer side of the goods-shed. The shed and the granary are supplied with water communication through tunnels under the roads to a basin on the south, and thence to the Regent's Canal; and lighters can receive or discharge their freights directly under the buildings. On the west of the goods-shed are the coal depôts and staiths. The coal arriving at the station is discharged in some cases directly from the waggons into carts alongside; in other cases it is discharged through hoppers on to weighing machines at a lower level, and thence filled into sacks. For this operation there is a frontage of 343 yards; and there is in addition a coal depôt in Cambridge Street, adjoining the goods-yard, with a frontage of 196 yards. There is a coal and stone dock or basin connected with the Regent's Canal, where barges are loaded directly from the coal-waggons, either through doorways in the bottom of the waggons or by discharging the coal from the sides of the waggons into hoppers. There is also a hopper at the Cambridge Street depôt for the purpose of loading barges on the canal. Adjoining the canal basin there are numerous private wharves for bricks and other merchandise. To the north are the locomotive and carriage sheds for repairing the stock, also two engine-running sheds, one round and the other rectangular. The goods, mineral, and locomotive stations cover an area of about 70 acres, and the total area covered by the goods and passenger stations and the running lines to Copenhagen tunnel is upwards of 90 acres. The principal goods-shed and granary is 300 feet long and 175 wide, and the area occupied by the goods-warehouses, potato-market, coal-offices, and other buildings amounts to 83 acres. In addition, 1 acre is covered by open sheds and 1 acres by the stables and the engineers' shops. The enginesheds can hold eighty-four engines and tenders, and they, with the workshops, tanks, carriage-repairing shops, and sundry premises, cover 2 acres. There are in the goods, mineral, and engine yards 28 miles of single line of way and more than 250 sets of switches, 200 turn-tables for waggons, and one for engines and tenders; of that length of line 11 miles of sidings are used for coal-waggons.

It is unnecessary to dwell at length on the arrangement of small terminal stations for branch lines. Where the line is single a single platform suffices, the trains being light and moving only in one direction at one time,

In fixing intermediate stations the first step should be to get a Intergood map of all the places within the scope of the railway, and to mediate mark upon it the population of each place from the last parlia- stations. mentary census. The greater the number of stations, the more the travelling increases; for quick and cheap transit creates traffic. Stations, especially important ones, should be on the surface rather than on an embankment or a viaduct or in a cutting. Facilities of access in all directions from the surrounding districts, with good roads in the case of passenger traffic, and good water and railway communication for goods depôts, are obviously indispensable. For safety and regularity there should be an uninterrupted view along the line of railway-no sharp curves or complication of over-bridges -in the vicinity of a large station. Intermediate and junction stations should be situated on dead levels, since, when a good length of level can be had, with gradients falling from it both ways, there is the greatest possible facility for working the traffic. Falling gradients towards a station are objectionable, but cannot in all cases be avoided. When the station is situated midway between towns of such extent as to cause an equal flow of traffic in each direction, offices may be requisite on both sides of the line; but, where the bulk of the traffic tends one way only, it will be desirable to concentrate it on that side which involves the larger number of passengers and the greater extent of waiting space. 1 The headquarters of the locomotive and carriage department are at Doncaster station.

This rule, again, will be modified by the position of the town or the district whence the traffic is to be derived, especially if the railway lies on the natural surface and adjoins a public road, whether crossing on the level or otherwise. This last condition is the most frequent one; and, as some portion at least of the traffic must be expected to depart from the platform opposite to the offices, provision must be made for crossing with the least amount of danger to the public. When the passengers are numerous in both directions, over-bridges, as before stated, are objectionable; and in a surface-station an archway under the line is frequently impracticable. Some good authorities have adopted the plan of making the trains take up and set down the passengers at one platform only, when the platform may be made rather more than double the length of a single train, having crossings in the centre to communicate with both lines of rails, thus placing the trains when standing on the platform upon a loop-siding distinct from those lines. This system offers great convenience to the public when there is much first-class traffic and a large quantity of baggage; and it is especially applicable when the station partakes of the character of a terminus, or is used as a receiver from branch or neighbouring lines, offering, as it does, great facilities for making up and receiving trains which may run over a portion only of the main lines, as well as for attaching and detaching the carriages intended or used for branch traffic.

Junction The buildings and yards in junction stations may be placed in stations. the fork between the two double lines of railway forming the junction, or beyond the point of junction.

The

Midland Locomotive stations comprise two departments,-the running building and the constructing and repairing of engines and tenders. works. chief locomotive station of the Midland Railway at Derby may be taken as an example. It is contiguous to the passenger station, and is in communication with the main line by a number of sidings branching off at the north end of that station, near the bridge over the Derby Canal. The area of ground enclosed is about 80 acres, of which 12 are covered by buildings. The walls of the erecting shops are 28 feet high; those of the fitting and other shops are 20. The tools are 693 in number. The number of locomotives housed at Derby station (1885) is 289. There is room in the erecting shops for seventy-one locomotives. The workshops are capable of turning out 120 engines per year-say, thirty new engines with tenders, and ninety engines with new boilers, cylinders, and other working parts.

The carriage and waggon works of the Midland Railway at Derby are situated about half a mile south of the passenger station, with which they are connected by a double line of way branching out from the south end of the station. The works were built in 1875-76, on an enclosed piece of land 67 acres in extent, of which 19 are covered by buildings. There are 15 miles of single way within the enclosure. The workshops are built in blocks, separated by open spaces of at least 70 feet in width. They consist principally of seven large shops, of red brick, the walls being of a uniform height of 21 feet; four on the west side are devoted to the preparation of timber and the building and painting of carriages and waggons, and three on the east side to the manipulation of various metals, comprising the foundry and iron stores, the smithy and the machine and fitting shop. Each block of building is entirely surrounded by a 7-inch water-main continually charged with water at a pressure sufficient to throw a jet over the ridge of the roof of any of these buildings. Vehicular communication is carried on between the shops on the cast and the west side of the works by means of traversing tables, the rails for which are laid the entire distance across the shops from north to south, and intersect the nine principal lines of sidings flanking the shops. Both steam-power and horse-power are used for moving the traversers.

In

The saw-mill is 320 feet long and 200 wide. In the cellar underneath all the main shafting, pulleys, and belting are placed. About a hundred loads of oak logs are converted into plank or Scantling weekly. There are in all about a hundred machines for sawing and working wood. Outside the saw-mill are large crosscutting saw-benches, with circular saws 6 feet in diameter, by which logs of deal are cut to the required length before being taken into the mill. The waggon-shop is 320 feet long and 200 wide. The carriage building and finishing shop is 384 by 200 feet wide. the panel-shed fitted with louvre ventilators, mahogany panel boards, maple boards, &c., are stored for about two years, to be thoroughly dried and seasoned before being used in vehicles. The painting and trimming shop is 384 by 300 feet. It has seventeen lines of rails, each capable of holding ten ordinary vehicles. From the commencement to the finish, twenty-five distinct operations— pruning, filling up, rubbing down, painting, varnishing-are performed on a passenger carriage. Young girls and women-t -the children and widows of the company's servants who have lost their lives by accident in the service are employed on the light work of sewing, stuffing of cushions and backs of carriages, french-polishing, Washing and dyeing, cleaning and lacquering light brass-work and gilding.

The foundries, iron and brass, are 200 feet long by 90 wide. Two thousand tons of iron castings are turned out annually. There are the bar-iron stores 200 by 45 feet, the general stores 150 by 90 feet, and the mess-room 45 by 70 feet, providing accommodation for 500 workmen ; also two smiths' shops, one of them 225 by 200 feet, the other 140 by 200 feet; the machine and fitting shop, 400 by 225 feet; and the coal-waggon repairing shop, 350 by 300 feet. The carriage and waggon works just noticed are capable of turning out seven new carriages and eighty new waggons weekly. All the building of railway carriages for the Midland Railway is done at their works, and 80 per cent. of the new waggons are built here. Eighty per cent. of the carriages and 20 per cent. of the waggons are repaired here. The machinery of all kinds laid down for carrying on the business of the carriage and waggon works comprises 500 machine tools, 9 steam-engines, 1 gas-engine, 15 stationary boilers, 4 warming boilers, 3 steam traversers, 2 steam cranes, 2 steam travelling cranes, with a number of hydraulic cranes and overhead cranes.

One of the engine houses or sheds for engines on duty, at Gorton Enginestation, on the Manchester, Sheffield, and Lincolnshire railway, is sheds. shown in fig. 21. It is a rotunda of 150 feet in diameter inside,

FIG. 21.-Rotunda at Gorton locomotive station, to house the working engines. and is capable of holding seventeen engines with their tenders, leaving the entrance and exit lines clear. The advantage of this arrangement over the ordinary polygonal engine-house is in the absence of pillars for supporting the roof, of which there are twelve for a twelve-sided polygon; in this building there is but one column, at the centre. To the left of the entrance is a furnace for holding live fuel, from which the engines are lighted; and there are two lines of rail across the central turn-table, on one of which the engines enter and on the other depart. Between the rails of each radiating line a pit is constructed to afford access below the engines for inspection. The roof is of wrought-iron, surmounted by a louvre for ventilation, which is glazed to admit light freely." In the engine-shed of the North-Eastern Railway at Newcastle five ordinary engine-house rotundas have been replaced by a single rectangular building 450 by 280 feet with five turn-tables. shed has berths for ninety engines, and the extra space enclosed by the rectangular building as against separate rotundas is used for executing minor repairs.

This

Station Fittings.-The use of switches and crossings is to form Switches. a link of communication between one line of rails and another. They are either constructed with ordinary rails or with rails specially rolled, and are carried in cast-iron chairs spiked down to sleepers. The switch-rails are movable, and when worked independently are moved by rods to which heavy weights are attached, the function of the weights being to retain the points in one their normal position after they have been shifted for the passage position, and to act as a self-acting adjustment in restoring them to of a vehicle or a train. When only one of the terminal rails is movable it is called a single switch and is used only on sidings or branch lines of rail. The double switches, being more perfect in