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Obtaining an Act of Parliament.—The number of crude and ill-judged speculations brought forward in the years 1835, 1836, and 1837, led to the making of new standing orders, by which the facility of obtaining railway acts is much reduced. Many think that these regulations are now too stringent; and the very limited number of new undertakings sanctioned since they came into operation, though partly to be accounted for by other circumstances, appears to confirm that opinion. The present standing orders of Parliament require the deposit of detailed plans and sections of a proposed line of railway, with certain specified officers in the counties through which it is proposed to carry the railway, in the Private Bill Office, accompanied by books of reference, showing the owner, lessee, and occupier of every house or piece of land likely to be interfered with, long before an application can be made for an act. These plans, &c., are to be deposited, and notices of the intention to apply for an act are to be published in newspapers, at various times in February, March, and April, of the year preceding that in which an act is to be applied for; so that a whole year is allowed for interested parties to consider the scheme, and prepare for opposing or advocating it when before Parliament. Notices must also be given, personally, to all the owners, lessees, or occupiers of property on the line, before a bill is introduced. Before 1837 a period of about six months was required, instead of twelve,—an arrangement far more favourable to railway companies than the present. These preliminary steps are often taken before the formation of a company to carry the project into execution. A company must, however, be formed before a bill can be introduced; and a sum equal to ten per cent. of the estimated cost must be deposited in government securities. After the second reading the bill is referred to a committee, in which the merits of the project, the stability of the shareholders, with other circumstances, undergo a searching investigation. If the bill be opposed in this stage counsel are engaged, and witnesses examined, on both sides, often at an enormous expense. Clauses are often inserted, during the progress of the bill, for the special protection of parties whose property is likely to be injuriously affected by the railway.
A railway act forms the shareholders into a corporate body, and invests them with the necessary powers for the construction of the line. They are authorised to subscribe the estimated amount in shares, and also, usually, to borrow an additional sum equal to one-third of the share-capital, if necessary. The numerous matters embraced in the act frequently extend it to one or two hundred folio pages; and the present arrangements occasion so great an expense when a bill is opposed, that the cost of obtaining an act is often several thousand pounds. The London and Birmingham Railway Company spent more than 72,000l. in obtaining theirs, and the Great Western upwards of 88,000l. The London and Brighton is, perhaps, the most expensive contest of the kind that has taken place,—four or five companies having engaged in it for two successive sessions: when in committee, the expense of counsel and witnesses in the latter case is stated to have amounted to 1000l. daily for about fifty days.
The act of Parliament being obtained, the land required for the railway is set out and purchased. Where exorbitant claims are made for the land, or for compensation for injury caused by the severance of estates, recourse is had to a jury, who generally award a sum far less than that claimed,—frequently less than a quarter.
Formation of the Road.—Under this head is included the execution of those works necessary for the construction of a road (independent of the rails and finishing works) of the required level and width. These works consist of tunnelling, excavation, embankment, and masonry for bridges, viaducts, and other erections. They are commonly divided into convenient portions, and let to contractors under agreement to complete them at a stipulated price and within a specified time.
Tunnels are, in general, the most formidable works, and the time and expense of forming them can be least accurately calculated. Trials of the nature of the ground are made by boring. Being objectionable also on other accounts, tunnels are avoided as much as possible in the more recently designed railways.
Cuttings or excavations of great depth and extent are of frequent occurrence where the railway passes through high ground. The depth of cuttings is frequently from fifty to seventy feet, and occasionally even greater. One very extensive excavation through the Cowran Hills, on the Newcastle and Carlisle Railway, is a hundred feet deep. The degree of slope necessary in the sides of cuttings varies greatly in different soils. Rock will stand when nearly vertical; chalk varies from nearly vertical to a slope of one horizontal to one vertical, or an angle of 45°; gravel stands usually at one and a half to one; London clay from one to one to three to one, having in some instances stood at the former and slipped at the latter slope. Some materials are insecure at even a greater slope; blue soapy shale having, according to Lecount, slipped at an inclination of four horizontal to one perpendicular. The unexpected slipping of the slopes sometimes occasions much trouble and expense. The great cutting at Blisworth, on the London and Birmingham Railway, is an example of a convenient and economical method of passing through earth in which strata of rock occur. The railway is at a depth of fifty or sixty feet, the upper portion of which is rock, and the lower consists of a less solid material. Instead of making an excavation of the slope required by the lower strata, which would have rendered the removal of the superincumbent rock indispensable, the sides were made nearly vertical, and the rock was supported by an undersetting of masonry. The great breadth of ground occupied by the slopes of cuttings is a serious objection when they are in the vicinity of towns, or pass through valuable property, in which cases the sides may be made nearly vertical, and supported by retaining walls, so curved as to enable them to sustain the pressure of the earth. The extension of the Birmingham Railway to the Euston station at London is a very bold and handsome example of this kind of work. In designing the works of a railway, the amount of excavation and embankment should be balanced as nearly as possible, so as to avoid the necessity of depositing earth from cuttings in spoil-banks, or having to purchase additional land to supply material for the embankments. Attention to this point will sometimes decide which is most expedient, a short tunnel or an open cutting.
Embankments are the artificial ridges of earth formed to support the railway on a higher level than the natural surface of the ground. Their dimensions are often fully commensurate with those of cuttings, from which their materials are mostly procured. In the ordinary mode of proceeding, an embankment is formed simultaneously with a cutting, the earth-waggons proceeding filled from the excavation along a {72} temporary railway to the embankment, where they are tipped up to discharge their contents. A heavy embankment often forms the key, as it were, to the time of completing a railway. Tunnelling and excavation may be proceeded with at many different points, but an embankment, under ordinary circumstances, can be carried on only at the ends. Where the excavations do not afford sufficient material, embankments are partially formed of earth dug from trenches along their sides, and thrown up into the centre. This is called side-cutting, and, being an expensive proceeding, should be resorted to as little as possible. An important element in the cost of embankments is the length of the lead, or distance to be traversed by the earth-waggons between the points of filling and emptying. The sides of embankments, like those of cuttings, require a considerable slope, especially when the material is of an unfavourable nature. The earth should be deposited in layers of two or three feet thick, slightly concave on the upper surface; and, if time permit, it is well to allow one layer to settle before another is spread over it. The subsidence of newly-made embankments is a source of great expense, and sometimes of danger. It is usual to lay the rails in such a manner as to diminish the risk of accident from this cause, and to travel slowly over parts where a tendency to slip is observable, especially in wet weather; yet casualties will sometimes occur until these great earthworks are thoroughly consolidated. Allowance should be made for subsidence by making the embankments rather higher than they are intended to be finally. Great difficulties are experienced in embanking across marshy or boggy soils, which frequently sink under the weight of the earth deposited, and the ground at the sides bulges up. Judicious drainage may do much in such cases, and the insertion of a frame-work of timber to bind the earth together, and thereby check the unequal settlement of the embankment, has been tried with apparent success by Mr. Braithwaite on the Eastern Counties Railway. To prevent carriages which escape from the rails falling over the sides of an embankment, mounds of earth are sometimes raised along them. Embankments have been made across Chat Moss, on the line of the Liverpool and Manchester Railway, and in similar places. The difficulties arising from the yielding nature of the material are greatly obviated by drainage, for, when dry, the moss itself becomes a fit substance for embanking, and stands well at a slope of less than 45°. The railway is sustained on part of Chat Moss by a platform of timber and hurdles, covered with earth and broken stone. A peculiar kind of embankment required in hilly districts and along coasts, consists of a road on the side of a steep elevation, one side being supported by a sustaining or revêtement wall. An important work of this kind is being executed along the face of part of the Dover Cliffs, for the South-Eastern Railway, in which the revêtement wall is exposed to the sea. Similar constructions have been introduced on the Dublin and Kingstown Railway, where there is also a remarkable embankment across the strand at Blackrock, that, at high water, has the appearance of a mole stretching into the sea, which is allowed to pass through it by culverts. On the Preston and Wyre Railway is an extensive embankment in a similar situation, but, when completed, it is intended to exclude the sea. On the Stockton and Hartlepool line a sea-embankment of clay has been recently completed, the side being puddled and formed into such a curve as to bear the dashing of the waves. Retaining walls are occasionally used to diminish the space occupied by embankments. The Dublin and Kingstown Railway commences in this manner, arches being introduced at the intersection of streets and roads.
The earth-works on most of the great lines of railway in England are very extensive, in many cases averaging from 100,000 to 150,000 cubic yards per mile. On the London and Birmingham line alone the quantity of earth and stone removed was about 16,000,000 cubic yards. When completed, it is advisable to sow the slopes of cuttings and embankments with grass-seed, as their appearance is thereby improved, while the roots give cohesion to the surface.
The amount of masonry and brickwork required in the various erections of a railway is very great. The lining of tunnels, where the ground penetrated is of such a nature as to require support, forms a peculiar kind of work. Arching of almost every kind is more or less required in viaducts, bridges, culverts, and drains; and simpler work in the retaining walls, station buildings, and other necessary erections. Viaducts of great magnitude are often executed for the purpose of crossing valleys at an elevation greater than could be conveniently obtained by embankment, and also for entering or passing through towns. They are usually of stone or brick, but sometimes of wood or iron.
Bridges are required occasionally for crossing rivers, and very frequently at the intersection of roads, and as communications between severed property. From a statement by Lecount, in the ‘Encyclopædia Britannica,’ it appears that, taking the mean of nearly a hundred railways, the number of bridges averages about two and a quarter per mile. Besides ordinary arches of brick and stone, bridges consisting of cast-iron girders laid from one abutment to the other, and supporting a platform of flag-stones, iron plates, or planks of wood, are very common. When the railway itself passes over such a bridge, six ribs are used, the distances of which are so adjusted that four of them sustain the rails and the other two the parapets, leaving nothing necessary between the ribs or girders except a flooring of iron plates. By this arrangement great strength is ensured, and the depth or thickness of the bridge is reduced to a minimum, no ballast or road material being necessary. Wooden bridges of similar character are occasionally used.
Skew-bridges are introduced when the railway intersects any existing communication at an oblique angle. Such arches were built before the introduction of railways called them into general use; but as, in an ordinary road or a canal, a deviation from the straight line is of little consequence, it was seldom thought necessary to apply them, and it was customary to build the arch of the ordinary form, on the square, and accommodate the direction of the road or canal to it by curved approaches. But on a railway straightness is of great importance, and it frequently becomes necessary, in crossing other roads, to adopt a skew-bridge, in which the communications over and under the bridge form unequal angles with each other.
When the various works described are completed, with the requisite drains and fences, the road is ready for receiving those finishing works which entitle it to the distinctive name of railroad. The level of the earth-works, when completed, is called the formation-level, and is usually about two feet below the intended surface of the rails. The width of this surface is about thirty feet, exclusive of the side-drains and fences, and it is made a few inches higher in the middle than at the sides, in order to throw off water.