Railway curve

“ A sharp curve leading into or out of a terminal station or main-line stopping-station does not so much affect the train running as a sharp curve at an intermediate point between stations where the train may be expected to run at its maximum speed. Wherever it is possible it is very desirable to avoid sharp curves on inclines, because there are times when descending trains may acquire a considerable velocity, and wheels tightly gripped by the brakes have not the same facility for following the curves as when they are running free. ”

“ The speed of the train regulates the amount of super-elevation to be given on any particular curve, and to ensure smooth and safe running this amount must be maintained uniform all round the curve. On curves of small radius, guard, or check, rails are frequently placed alongside the inner rail, as in Figs. 30 to 33, to check the tendency of the engine to leave the rails and run in a straight line. ”

“ This necessarily involves a gauge of rail of about 6 feet 101⁄2 inches to 6 feet 11 inches, but 7 feet allows of its being done easily; it allows, moreover, of a different arrangement of the body: it admits all sorts of carriages, stage-coaches, and carts to be carried between the wheels. And what are the limits in the case of the Great Western Railway, as compared to those on Irish railways? Gradients of one-fifth the inclination, very favourable curves, and probably the largest traffic in England. ”

“ On the London & North-Western there are more than sixty through down trains, taking no account of local trains, each day passing over the same line of tracks, among which are express trains which stop nowhere, way trains which stop everywhere, express-freight, way-freight, mineral trains and parcel trains. On the Midland road there are nearly twice as many similar trains on each track. On the Metropolitan railway the average interval is three and one-third minutes between trains. ”

“ But besides the above number of passengers, over one hundred and sixty-two million tons of minerals and merchandise were carried by railway in the United Kingdom in 1873, besides mails, cattle, parcels, and other traffic. The distance run by passenger and goods trains in the year was 162,561,304 miles; to accomplish which it is estimated that four miles of railway must have been covered by running trains during every second all the year round. ”

“ Block-Telegraph Signalling.—However complete the outdoor signals and interlocking at any station, they can only control the movement of trains within their range, and something more is requisite to ensure the safe working of the traffic over the long lengths of line between stations. For some years a time-interval was allowed for the working of trains following one another on the UP and DOWN lines of a double line railway, no train being allowed to leave a station sooner than a fixed number of minutes after a previous train had started in the same direction. ”

“ Besides the passenger trains there were, in 1865, 2,108,198 goods trains, heavily laden with merchandise and minerals, or at the rate of 6,060 trains on each week day, and half that number on Sundays, Christmas Day and Good Friday, making a total each day of 16,447. At the end of 1865 there were, as has been frequently stated in these pages, 13,289 miles of railway open for traffic; at present (October, 1867) the number of miles is fully 14,300, and there cannot be less than 13,000 passenger trains a day. The proportion of trains arriving late to trains arriving to time is not three per cent. ”

“ But gradually, as people began to return to their farms and sheep-runs, and the agricultural possibilities of the State again seemed worth considering, the numbers of railway-lines began to increase, and during the twenty years which followed 1874 no fewer than 2,498 miles of railway were constructed and opened for traffic, since which only 348 miles of line have been added, chiefly in the wheat-growing districts of the North-West. ”

“ On the Semmering a long train has to be divided into two or three portions, to enable it to surmount these steep slopes, which frequently are as rapid as one in forty, even on the viaducts and in the tunnels. The reader has only to notice the numbers on the gradient indicators by the side of an English railway, to be able to judge what an incline of one in forty is like.
But if one in forty seems steep, what shall be said of one in four, which is the gradient of a large part of the Rigi railway? ”

“ It may be considered, as a general rule, that there are on an average, twelve men employed on each mile of railway in the United Kingdom. Taking the present length of railways as 14,300 miles, [73] this would make the number about 172,000. Of course on many of the railways, especially on those opened in recent years, which are single lines, and run through districts where the population is sparse and the trains infrequent, there is nothing like that average number employed. ”

“ The time allowed for passenger trains is one hour and fifty minutes, being an average of fourteen miles an hour; for goods trains, two hours thirty minutes, or at the average rate of about ten miles an hour.
There was until just recently, a race running between the engineers at the Brenner and at the Mont Cenis, and it was, until the beginning of August, 1867, uncertain which of them would have the honour of being the second railway upon which the locomotive had crossed the Alps. ”

“ Yet such is not the case within the limits we are now treating of: a 7-feet rail requires no wider bridge or tunnel than a 5-feet; the breadth is governed by a maximum width allowed for a loaded waggon, or the largest load to be carried on the railway, and the clear space to be allowed on either side beyond this.
On the Manchester and Liverpool Railway this total breadth is only 9 feet 10 inches, and the bridge and viaducts need only have been twice this, or 19 feet 8 inches ”

“ It is not advisable to attempt to spring a 14 lb. rail round a sharper curve than five chains, or an 18 lb. rail beyond ten chains radius.
The result of attempting too much springing is that the rails, under the traffic and changes of temperature, work outwards at the joints and make “dog legs” more or less serious. Where the ballast is of a loose dry nature very little, if anything, can be done with springing. I have enlarged upon this subject of rail-laying because it is of prime importance to a good road, and a matter that, on narrow-gauge lines, does not receive the attention it requires. ”

“ And I believe also that, considering the absence of most of the causes of accidents, there will even be less liability of interruption and less delay in the average resulting from accidents than in the ordinary double locomotive railway.
By the modification of the gradients and by reducing the curves to 1,000 feet radius where any great advantage can be gained by so doing, and by constructing the cuttings, embankments, tunnels, and viaducts for a single line, a considerable saving may be effected in the first cost. ”

“ And thus, when a train starts on a journey of it may be hundreds of miles, it is signaled on from station to station, and "lives along the line," until at length it reaches its destination, and the last signal of "train in" is given. By this means an immense number of trains can be worked with regularity and safety. On the Southeastern Railway, where the system has been brought to a state of high efficiency, it is no unusual thing during Easter week to send 570,000 passengers through the London Bridge Station alone; and on some days as many as 1200 trains a day. ”

“ The permanent way should be made a thoroughly sound job, as it will then cost but little for repairs. Particulars of what is recommended will be found in Sections III. and IV. I am no advocate of portable railways, which may be well enough for hand trains, or even for horse traction, but a locomotive requires a solid and clean road if it is to work to advantage.
It is often possible to carry a narrow gauge railway by the roadside or, as at Eaton, over pasture lands without the necessity of fencing the line in. ”

“ Where there are only two lines of rails to serve for the UP and DOWN service of a heavy passenger and goods traffic, it is imperative to restrict those lines as much as possible to the actual transit of trains, and not to block them by unnecessary occupation for shunting purposes. A goods train running a long distance collects waggons from many roadside stations, and at some of them several waggons will be taken on, to be forwarded to various and widely distant destinations. ”

“ These scattered bits of road here and there were, in after years, as the possibilities of railroad development began to dawn upon the minds of far-seeing men, united by connecting links and reorganized into roads of much greater length. In fact some of the most difficult features of the railroad problem of the present day grew out of the failure of projectors of railroads{435} in the early days to grasp the meaning of the system which they were instituting. France, Germany, Belgium and other European cities have had no serious railway problem. ”

“ In others the curves may be made of easy radius, at a comparative moderate extra outlay, if the character of the line and description of traffic to be accommodated will warrant the expenditure. For main through lines, with heavy, high-speed traffic, it is advisable to have the curves of large radius, so as to avoid the necessity of reducing speed when passing round them. ”

“ The balance is built and operated on private right of way, and goes around, rather than through, the cities. The tracks are standard gauge and of standard railroad construction, were, at the time they were laid, of higher class than those of the Southern Railway Company in the same territory, were intended for handling substantial interchange freight traffic in connection with steam railroads, have the same ruling grades as the latter in the same territory, and are of 80-pound rail. ”

“ The atmospheric system of working railways found favour for a time, and was tried on the West London Railway, on the South Devon system, and in other parts of Great Britain, also in France, but nowhere was it permanently successful. ”

“ There is not an article of commerce that the railway cannot move—does not move; there is not an article of commerce that the railway does not move at speed never less than eight and generally ten times as great as it was [153] by canal, until competition stimulated the pace of the latter. To what extent? From the once normal rate of two to that of three miles an hour—no more. ”

“ It is probable that a traffic of 5,000 tons annually over a mile of line is the smallest amount that would repay the construction of a narrow gauge railway, for the estimate has been based upon the narrowest line which can profitably be employed. ”

“ As passenger carriages pass from one company’s line to another’s, it is essential for the public safety that, although the widths of the carriages on the different lines may differ from each other, the widths across the carriages from the outside of the continuous footboard on one side, to the outside of the continuous footboard on the opposite side, should be identical for the carriages of all railway companies, so that the lines of rails may be laid at the proper distance from the edges of the passenger platforms. ”

“ No station to be constructed, and no siding to join a passenger line, on a steeper gradient than 1 in 260, except where it is unavoidable. When the line is double, and the gradient at a station or siding-junction is necessarily steeper than 1 in 260, and when danger is to be apprehended from vehicles running back, a catch-siding with points weighted for the siding, or a throw-off switch, to be provided to intercept runaway vehicles at a distance outside the home-signal for the ascending line, greater than the length of the longest train running upon the line. ”

“ Circumstances vary on the different roads, but it is safe to say that eight to ten per cent. of all rails in the track must be renewed every year. This brings the average life of the steel rails down to about twelve years, under ordinary conditions. On some divisions, however, where the traffic is frequent, and in yards where a good deal of switching is done, and the rails are under pressure constantly, the average is, of course, very much less—even as low as two or three years. ”

“ Every one of the heavy works on a line, whether lofty bridges, long viaducts, or costly tunnels, not only enormously increase the original expenditure of the undertaking, but also entail large annual outlay in the necessary constant supervision and maintenance.
Each particular scheme will have to be discussed on its own individual merits. The heavy, high-speed passenger traffic line will suggest light gradients and easy curves, while on secondary lines and in thinly populated districts it may be prudent, for the sake of economy, to introduce sharper curves and heavier gradients. ”

“ To see waggons with flat wheels drawn over cast-iron rails one yard long by a horse, cannot fail to interest those who watch the workings of railways, and it most clearly shows the great improvements made and the perseverance which has been required to develop the present gigantic railway system out of such small beginnings. ”

“ The extent to which the average speed of trains is affected by the mode of construction of a railway is strikingly illustrated by the following table, which gives particulars of the curves and gradients, and the speed of the trains, upon the main line of the London and North-Western Railway from London to Carlisle, upon the Buxton Branch, the Central Wales line, and the Merthyr, Tredegar, and Abergavenny Branch. ”