Railways. At the present time railways form in most countries of the world the chief means of internal communication. Their influence in stimulating industry and in creating new branches of trade since their introduction into England in the year 1825, and into other countries at slightly later periods, has been simply incalculable. The subject is such a wide one that it can be most conveniently dealt with under the following heads: -
(b) Railroad Location and Permanent Way.
(e) Locomotives, Carriages, and Waggons.
(f) Statistics of Traffic, Mileage, and Rolling Stock.
(a) History. In his fine work, Das Eisenbahn-Geleise, Haarman traces the history of permanent way back to the times of Strabo, Diodorus Siculus, and Herodotus. The history of the railway, however, is not the history of permanent way so much as the history of the locomotive. It was the motive-power in the form of the locomotive that first made railways possible, and for the first locomotives we must look back to the times of Cugnot (1769), Trevithick (1802), and Hedley (1815). But no advance was made in this means of internal communication until the opening of the Stockton and Darlington Railway in 1825, and the famous Rainhill trials, in which the Rocket came out victor and established the fame of George Stephenson. Even then considerable opposition from vested interests delayed the spread of railways, and it was not until after 1840, and during the speculative time of the Railway Mania, that lines were built rapidly. Since then progress has been steady and sure, and there is but little of importance to record. Other countries have had similar experiences, but in America, during the last thirty years railway construction has been surprisingly rapid. The history of railways in the future will probably not be much concerned with construction, as most civilised countries are now covered with complex networks of lines, but will deal with struggles between these wealthy corporations and the State, labour, and trade interests. We may ultimately, as in Germany to-day, see State purchase.
(b) Railroad Location and Permanent Way. It is necessary, before laying down the permanent way of a railway, that careful comparison of all the likely routes between the points to be connected by the line should be made. Definite rules have here only a limited application, as the circumstances vary so greatly in each case. It is wise, however, to avoid heavy grades and curves of small radius as far as possible. Heavy grades always limit the load that can be taken by the locomotive, and, if very severe, require double engine-power, this resulting in largely increased expenditure. In level countries, where there is a choice of routes, it is, as a rule, unwise to neglect any points of importance lying at short distances from a direct line drawn between the towns to be connected. By judicious deviations these points can always be served by the main line without greatly increasing its length between its extreme points; the result is, as a rule, large extra traffic. Having decided upon the route the line is to take, the earthworks and cuttings are formed and the bridges erected. The former are sloped according to the nature of the soil, and the latter are so constructed as to bear the heaviest loads that will travel over them. Tunnels, viaducts, and other large works receive special treatment, according to the conditions governing their establishment. Finally a bed of specially-prepared ballast is laid down, on which what is known as the permanent way is placed. Permanent way consists of sleepers, chairs, keys, fishplates, and rails. The sleepers are in most cases of wood (which is creosoted or otherwise treated to prevent decay), but of late steel sleepers have been rather largely used. In nearly all cases sleepers are placed crosswise, though on the Great Western Railway there are many miles of longitudinal sleeper road. This latter gives easier running but renders repairs to the road very difficult. Chairs, keys, and fishplates are fastenings used to connect the rails with the sleepers, or with one another. Rails are now generally made of steel, in sections about 30 feet long, weighing from 75 to 100 lbs. to the yard. In England the bull-headed type is used, but on the Continent and in America the broad-base Vignoles pattern, which dispenses with chairs and keys and is simply bolted or spiked to the sleeper, has found favour.
(c) Signals. In the early days of railways the methods adopted to warn the driver of danger on the line ahead were exceedingly primitive. As time went on and traffic increased, it was found necessary to devise some more certain means of protecting trains. This resulted in the adoption of the Time System, under which trains were not allowed to follow one another on the same metals until after a certain interval, generally five to ten minutes, had elapsed. Although working well on lines with a small traffic, it was soon found that a space interval was more efficient to prevent accidents than the time interval. This method, at present employed in the United Kingdom almost solely, and on the Continent of Europe and in the United States to a partial extent, is known as the Block System. A line worked on this plan is divided into sections of various lengths, each furnished with a signal cabin. The signalman, being advised of the approach of a train, asks, by means of special instruments, the man in the box ahead if the line is clear. On receiving an affirmative reply, he is enabled to lower his signals. It will thus be seen that two trains can never occupy one section at the same time, and herein lies the great merit of the Block System.
It is not sufficient, however, to protect trains in this manner, but it is also necessary to ensure that points at junctions should be set for the particular line about to be travelled over before the signal for that line is lowered, and that, when once a line is made for a train, all other signals giving access to points fouling this line should be locked at danger. This is effected by interlocking the levers working such points and signals by means of ingenious appliances known as locking frames, located in the signal-boxes. As in the case of the Block System, this country considerably leads all other's in the interlocking of its points and signals.
In the limited space at our disposal it is impossible even to mention the numerous clever mechanical devices that are in use on railway lines to provide for special cases and to meet emergencies. It will only be necessary to point out that the signal-posts should, as a rule, be high and have a clear sky background, so as to enable them to be plainly seen by the drivers of oncoming trains. Experience shows that semaphore arms are more easily distinguished than Circular discs, and that the most convenient colours for signal-lights are red for danger and green for clear.
(d) Stations. Railway - stations are built at intervals along the line to serve the requirements of the neighbouring population. They may briefly be divided into passenger and goods stations. The smaller type of passenger station is generally furnished with tioket-office, waiting- and retiring-rooms concentrated together on one side of the line, and a small shelter on the other platform. The goods service is most conveniently performed when the loading and discharging shed is close to the main passenger buildings, and so under the surveillance of the station-master. Stations of a larger type, such as those for junctions and small towns, have in many cases waiting-rooms for each class, refreshment-rooms, and other conveniences. Overbridges on railways should be provided to enable passengers to cross from one platform to another. The goods station is frequently quite independent of the passenger in towns of moderate importance. It should be furnished with loading and discharging platforms, cranes, weighbridges, and storeroom. It should always, if possible, be built on the same side of the line as the large manufactories, etc.
Stations of the largest sort have, of course, more complete installations still, and the goods service is quite distinct. Examples of the largest passenger stations in this country are those at Birmingham, Carlisle, York, Perth, St. Pancras, Liverpool Street, etc., and abroad, at Paris, Frankfort, Cologne, Milan, etc. ; and in America at Philadelphia and Jersey City. In England it is always customary to provide a raised platform, nearly three feet high, but on the Continent, where passengers are confined to the waiting-rooms until a few minutes before the train starts, the platforms are rarely higher than six inches.
At the largest centres depots for housing, coaling, watering, and repairing of locomotives, etc., are established. They should adjoin the passenger and goods stations, but be kept quite distinct from them. Water-tanks, coal-shoots, ashpits, and turntables are also necessary. Difference of opinion seems to exist as to whether a rectangular or circular building is more economical. Some of the largest locomotive depots in this country are those at Crewe, Derby, and Swindon, and in America, at Altoona.
(e) Locomotives, Carriages, and Waggons. Since the days of George Stephenson's famous Rocket the locomotive has, of all the factors going to form a railway, undergone perhaps the least change. It consists now, as then, of a fire-box in which combustion takes place; of a boiler filled with water surrounding tubes through which the heated gases given off by combustion in the fire-box, flow, heating the water on their way and converting it into steam; of a pair of cylinders (or in compound engines three or perhaps four cylinders), to which the steam is conducted from the boiler by suitable pipes; of a piston-head, moving steam-tight in this cylinder, and attached to a piston-rod, which, connected by cranks to the axle of the driving-wheels, revolves these latter; and of eccentrics, which are so fixed to the axle and connected with the valve-motion that steam is admitted as desired to the cylinders. These are the main features of almost all locomotives; minor details, of course, vary in particular cases, but not to any great extent. There are, for instance, bar frames and plate-frames, Wootton and Belpaire fireboxes, etc.
But although there is great similarity in the main points of locomotive construction, there is considerable variation in size and weight. In the old days single-driver locomotives were largely used; but, as trains grew heavier and faster, it was found that adhesion was insufficient, and accordingly the load on the driving wheel was increased until it was as heavy as the permanent way would bear. Then, in order to distribute weight, four-coupled engines were introduced, and these are now, with driving wheels about 6-1/2 to 7 feet in diameter, used almost solely for passenger train working. For goods traffic six-coupled locomotives with wheels about five feet give the best results, and for heavy trains on severe grades eight and even ten coupled types are employed. Suburban traffic is generally worked by tank engines, which carry their water at the side of the boiler and their coal in a small bunker behind, and thus dispense with a tender. Main-line locomotives of recent years weigh in most cases more than 70 tons, including tender.
Carriages and waggons form a considerable part of the rolling stock of a railway. The former are constructed on the compartment system in this country and on the Continent generally; but in America, where there is virtually only one class, against three here, the vehicles are open throughout. Each method has its advantages, the balance being probably rather in favour of the American style. In the United States and our own country passenger carriages are much more comfortably upholstered than on the continent of Europe, internal dimensions are also larger, and there is more window space and greater cleanliness in the carriages of the lowest (or third) class. Some attention, however, remains to be paid to heating and lighting.
Besides the ordinary passenger rolling stock, special vehicles for dining, sleeping, etc., are provided at somewhat higher charges. These vehicles are generally mounted on bogie trucks, and are decorated and upholstered (especially in America) at considerable cost. In England dining cars for third-class passengers have lately been tried with some success, the only objection being that the dead weight of these carriages (over 30 tons) compares unfavourably with ordinary vehicles of similar capacity (12 to 14 tons).
Railway waggons should be constructed as strongly as possible, in order to resist shocks in shunting operations. They may be divided into covered waggons and open waggons, the former being generally used for valuable goods, meat, etc. Besides the ordinary types used for conveying merchandise and minerals, special vehicles have been constructed for the conveyance of fish, frozen meat, oils, tar, heavy guns, etc., which need not be described in detail here.
(f) Statistics of Traffic, Mileage, and Rolling Stock. The following table gives some idea of the importance of railway interests and railway traffic in six of the leading countries of the world. The figures are brought up to as late a date as possible: -
|Country||Length in Miles||Locomotives||Carriages||Waggons||Gross Receipts (?)|
|Great Britain and Ireland||21,174||15,552||35,021||499,904||85,922,702|