Railway tunnel

“ Trains coming through the tunnel from France were to emerge into the daylight and the ordinary open air of England either from a four-mile-long access tunnel connected to the South-Eastern's railway line at Abbots Cliff or—this was a favored alternative plan of Sir Edward's—at Shakespeare Cliff via a station to be constructed in a great square excavated a hundred and sixty feet deep in the ground, which would be covered over with glass, lighted by electric light, and equipped "with large waiting rooms and refreshment rooms." ”

“ It is hardly necessary to say that the great rival to the Mont Cenis or Summit Railway is the railway that is to be laid through the tunnel, which, in the official documents of both France and Italy is denominated “The Great Tunnel of the Alps.” But before we enter upon the description of this tunnel, an account of subterraneous construction from the earliest period we have been able to trace tunnels, may not be uninteresting.
Tunnelling through hills and mountains is not exactly “as old as the hills,” but the practice, nevertheless, is of great antiquity. ”

“ This tunnel is for wagons and other heavy carriages; and as the engines which are to draw the trains along the railroad do not enter these tunnels, there is a large building at this entrance which is to be inhabited by steam engines of a stationary turn of mind, and different constitution from the travelling ones, which are to propel the trains through the tunnels to the terminus in the town, without going out of their houses themselves. ”

“ Besides developing plans for a bored tunnel—the projected double-rail tunnel, interconnected at intervals by cross-passages, is essentially a modern version of William Low's plan of the 1860s, with an extra small service tunnel being added between the main tunnels—the Study Group's engineering consultants developed in detail schemes for a Channel bridge, an immersed railway tube, an immersed road tube, a combined immersed tube with two railway tracks, and a four-way road system on two levels. ”

“ This, Adams said, was to reinforce the tunnel at the point where it passed underneath the railway line. We went on again, this time walking on a dirt floor, and then we came to a timbered junction, from which the tunnel branched off again to the right in the north-east direction that was originally intended to bring it into line with the gallery at Shakespeare Cliff, while to the left there was a low-roofed chamber that probably once housed a siding and a maintenance workshop for the Beaumont boring machine. ”

“ When a railway line is to be carried across a range of mountains or hills, the first question which arises is whether it is better to construct a tunnel or to make such a détour as will enable the obstruction to be passed with ordinary surface construction. The answer to this question depends upon the comparative cost of construction and maintenance, and upon the relative commercial and structural advantages and disadvantages of the two methods. In favor of the open road there are its smaller cost and the decreased time required in its construction. ”

“ We knew as a fact that, during the early construction of railways in England, our engineers resorted to tunnels to avoid gradients and curves (especially the former) that would almost be considered favourable at the present day. As experience increased and the power of the locomotive was developed, so did the amount of tunnel [371] work diminish. Hence it is that if the three estimates just stated be correct, the proportion of tunnel to railway on the 1st of January, 1856, was one mile to every 115; on 1st of January, 1863, one to every 144 miles; on 1st of January, 1867, one to every 154. ”

“ Two steam locomotives which were being stored at Weehawken (part of the plant from another contract) , were used for hauling the cars in place of the electric ones used with the 2-ft. gauge railway.
Tunnel Transport.—The track used in the tunnel was of 2-ft. gauge, laid with the 20-lb. rails previously used in driving the iron-lined tunnels. The mining cars (previously mentioned in describing the driving of the iron-lined tunnels) were used for transporting the invert concrete, although, for most of the work, dumping buckets carried on flat cars were used. ”

“ Tunnel No. 2, being left as a heading, is driven on that side nearest to No. 1, to minimize the length of the cross-headings, and measures 10 ft. 2 ins. wide by 6 ft. 7 ins. high. Masonry is used only where necessary, and in that case is so built as to form part of the lining of the tunnel when eventually completed. Concrete is put in to form a foundation for the side wall, and a water channel. The cross-headings, connecting the two parallel headings, occur every 220 yds., and are placed at an angle of 56° to the axis of the tunnel, to avoid sharp curves in the contractors’ railway lines. ”

“ No attempt should be made to carry a tunnel through material which has been disturbed or at all affected by any natural slip or cleavage, as although the strata may be hard and compact in themselves, they have really no solid or fixed foundation. The sliding away, once initiated, is certain to continue, and, accelerated by the tunnelling operations, will most likely, sooner or later, crush in the tunnel and sweep away every vestige of the work. ”

“ Taking into account such economic advantages, the great boon to tourism that they believe a tunnel would represent, and the intangible psychological impetus that they claim a fixed link between France and Britain would give to the dream of a politically as well as economically united Europe, the pro-tunnelers believe that the construction of their railway under the Channel would be just about the greatest thing to happen to Britain in this century. ”

“ The first man to perceive and seize upon the benefits to be gained by combining the two systems was, most fittingly, Greathead. Although he had projected the technique earlier, in driving the underground City and South London Railway in 1886, he brought together for the first time the three fundamental elements essential for the practical tunneling of soft, water-bearing ground: compressed-air support of the work during construction, the movable shield, and cast-iron, permanent lining. ”

“ The original construction of many American railway tunnels with a timber lining to reduce the cost and hasten the work has made it necessary to reline them, as time has passed, with some more permanent material. In most cases the work of removing the old lining and replacing it with the new masonry has had to be done without interfering with the running of trains, and a number of ingenious methods have been developed by engineers for accomplishing this task. ”

“ Occasionally favourable opportunities present themselves for making horizontal shafts. For a portion of its length the tunnel may be located at no very great distance from the precipitous sides of some deep mountain ravine, or run near to the cliffs on the sea-coast, and advantage can be taken to drive a lateral heading or gallery through which the material from the tunnel excavation may be conveyed and thrown out into the gorge or seashore below. ”

“ Of the Sapperton tunnel on the Birmingham and Gloucester section of the Midland railway, 1,760 yards long, [140] Mr. Storrow says, “the grade is very steep, 1 in 70, or 751⁄2 feet to the mile. Hence, in running up the tunnel a great deal of power is required, and an assistant locomotive is kept constantly in use. This, of course, creates a large additional development of smoke and steam, so that after the passage of a single heavy freight train up, the smoke would fill the tunnel for hours, and be quite offensive. ”

“ Taking it as a whole, I don't think there is another such a piece of work in the world. It is the greatest work that has yet been done of this kind, and there has been less repairing than is usual—though an engineer might well be beaten in his calculations, for he can not beforehand see into those little fractured parts of the earth he may meet with." As Stephenson had promised, the invert was put in, and the tunnel was made perfectly safe.
(Map of Midland Railway)
The construction of this subterranean road employed the labor of above a thousand men for nearly four years. ”

“ There are altogether eighteen tunnels along the 151⁄2 miles of picturesque line of railway between Liege and Verviers; they are all short, none exceeding 400 metres in length; their cost was exactly £50 a metre forward. There is only one long tunnel in Switzerland, that of Hauenstein near Olten, on the railway between Basle and Berne, its length is 2,731 yards, and, notwithstanding the numerous difficulties which attended its construction, its cost was only £80 per yard. It might be expected that in an undulating country like Switzerland there would be a great many tunnels on its railways ”

“ The feasibility of combination rail-and-highway tunnels to eliminate the costs of snow removal or protection and to reduce grades over some western mountain passes, should be carefully investigated. It will be desirable to study at numerous points the possibilities of providing in a single structure, whether bridge or tunnel, for the crossing of rivers and other bodies of water by interregional routes and main railway lines. ”

“ A few years ago people could think or speak of nothing else for the Alps but tunnels; there was to be a tunnel railway through the Simplon, one through the St. Gothard, and as immediately to the eastward of the Great St. Gothard range, there is a rapid diminution of elevation of the Alpine mountain, no less than three passes were named as suitable for tunnels, the special advantage of each being that they could be constructed by means both of shaft and of adit. ”

“ The time for passenger trains through it is six minutes, or at the rate of 30 miles an hour; the time for goods trains is nine minutes, or at the rate of 20 miles an hour. The deepest portion of the tunnel is 600 feet below the upper surface of the mountain.
On the 3rd September, 1867, we came through the Shepherd’s Well Tunnel of the London, Chatham and Dover Railway, 2,376 yards long, against the gradient, which is 1 in 100, or 53 feet in the mile for two-thirds of its length, and the remainder nearly level, in two minutes fifteen seconds ”

“ Tunnels cannot always be delayed until the heading is cut through for the entire length. In many cases the heading, the full-size excavation, and the permanent lining have all to be carried on at the same time, but as the work of the heading is smaller in extent, that portion of the operations can usually be kept well in advance of the others. The critical moment arrives when the headings from opposite directions meet, as any deviation or want of coincidence must be adjusted in the portion of the tunnel still remaining to be opened out to full size. ”

“ The bridges over the open cutting were commenced, and the cutting itself lowered to the right Progress of the work—1883. level from its eastern end for a length of rather more than a quarter of a mile, when two steam-navvies were brought upon the works, and started to take out the excavation. A shaft was sunk at a point rather more than a quarter of a mile east from the eastern tunnel face, where a public road and one of the main drains of the level crossed the railway. ”

“ It was a sombre snowy afternoon, and the gas-lamps were lit in the big reverberating station. As he paced the platform, waiting for the Washington express, he remembered that there were people who thought there would one day be a tunnel under the Hudson through which the trains of the Pennsylvania railway would run straight into New York. ”

“ Instead of climbing far up and then coming down in long, slow curves, the train can run quickly straight through.
Tunnels are hard to dig. They often have to be blasted out of solid rock. So the builders don’t make them any bigger than they have to. Of course, there’s not room for a man to stand up on top of a freight car{61} as it goes through a tunnel. To protect brakemen who might forget, there is a device called a tell-tale close to the mouth of a tunnel. It is simply a fringe of cords hanging down from a tall bar across the track. ”

“ They never quite removed the machine from the heading when they were finished, but it was maintained right up to the outbreak of the Second World War, when it became derelict."
Adams and I walked back to the car. As we did so, he revealed himself as being pro-tunnel. "It's a tragic thing, this tunnel business, I think. If the tunnel had been built forty or fifty years ago, just think of what an asset to Europe it would have been," he said. We packed ourselves in, and Burgess drove us down a very rough, narrow road to the level of the railroad line. ”

“ To penetrate them by tunnels, except in very rare cases and short distances, is inexpedient; for the travelling steam-engine generally used on railroads cannot be used in a tunnel, owing to the air being rendered unfit for breathing by the effect of the fire. Besides the resistance that the air in the tunnel will give to the carriage passing through it, even were tunnels practicable, the great original expense of construction forms a strong objection. ”

“ There are two important secondary techniques for opening subterranean and subaqueous ways, neither a method truly of tunneling. One of these, of ancient origin, used mainly in the construction of shallow subways and utility ways, is the “cut and cover” system, whereby an open trench is excavated and then roofed over. The result is, in effect, a tunnel. The concept of the other method was propounded in the early 19th century but only used practically in recent years. ”