II 



KAI1.WAV 



RAILWAY. 



tie 



Perdonnct' ' Traitc 1 ' already referred to. In settling the am. .nut .>i" 

 cutting to I* executed on a lino of railway, it U essential to boar in 

 niiinl that it should, ai nearly ai possible, balance the amount ..i tlio 

 embankment ao a* to avoid i>ith<T the n. , v-.-ity for purchasing ground 

 to receive the spoil or lurpliu earth, . .r to furnish the material t r the 



i of the Kuik from side-cutting. The Tring cutting on the 

 Binningham Railway, and the Gadelbach cutting on the Ulru and 

 Augsburg line, are amongst the largest works of thu description \.t 

 executed : the former contained nearly 1| millions of cubic y.t-'i ; the 

 Utter about 1,410,000 cubic yard*. 



The embankments are formed simultaneously with the cutting*, and 

 the materials obtained from the latter arc transported by barrows, 

 carts, or waggons, to the former, according to the distance ; barrow - 

 work ceasing to be economical when the distance to be traversed ex- 

 ceeds 100 yards, carts are then used ; and when the length of transport 

 attains a quarter of a mile it U decidedly cheaper to use waggons upon 

 temporary roadways, made in railway works of the metals, or rails, to 

 be afterwards used for the permanent way. As embankment M can thus 

 only be commenced from their two ends at a time, it follows that 

 when they are of considerable dimensions they may even regulate the 

 duration of the works upon a railway, because bridges or tunnels can 

 be commenced at once in several places. Time may occasionally be 

 aared by the use of temporary wooden staging, and by carrying on the 

 work in several layers or strata ; but if the length of lead (or the dis- 

 tance traversed) be great, it is very rarely indeed that more than from 

 2000 to 2500 yards cube cnu l>e tipped at one end of a bank in a day. 

 The earth in small banks ia often rammed to ensure its uniform com- 

 pression, and even in the very rough and ready manner in which railway 

 works are effected, especially in England, the precaution of punning 

 the earth at the back of culverts, or bridges, is generally adopted. For 

 large embankments it would be practically impossible to attempt to 

 secure this theoretical perfection, and the earth is in them simply cast, 

 or tipped, from a waggon, and ia allowed to settle by its own weight, 

 and by the effect of time. It is important, therefore, to observe that 

 the earth taken from a cutting will, in the beginning, occupy a space 

 about ^ greater in the bank than it did in its natural position ; and 

 that even after they have settled during three or four years the ma- 

 terials in a bank will still occupy a volume Jth greater than they did 

 originally. The subsidence of new-made banks is indeed a source of 

 danger and of expense on all railways, and it must be guarded against 

 in the most careful manner; allowance should be mode for such sub- 

 sidence, by keeping the crowns of the banks above the intended 

 finished level. 



In executing heavy embankments care must also be taken to ensure 

 that the ground upon which they ore to be founded should not be 

 exposed to lateral displacement, or to any serious amount of vertical 

 compression ; although the latter objection ultimately resolves itself 

 simply into a question of money. Accidents of this description fre- 

 quently occur upon the banks of rivers, or in alluvial districts ; and 

 the most efficient mode of dealing with them is to isolate the seat of 

 the bank from the surrounding ground, in such a manner as to cause 

 the whole compression to take place vertically. In marshy and boggy 

 grounds judicious drainage may do much good ; but the system 

 adopted in carrying the Liverpool and Manchester Railway over the 

 Chat Moss, of supporting the earth to be deposited upon a stratum of 

 hurdles, or the one used by the Dutch engineers of forming as it were 

 a floor of fascines, or of bundles of reeds, must in many instances be 

 resorted to in addition to the introduction of lateral drains. On the 

 Munich and Augsburg line an efficient method of carrying the rail- 

 way embankment over a peat-bog about 16 feet deep was used, which 

 it may perhaps be desirable to mention here ; it consisted in sinking a 

 aeries of square holes, " en echiquier," about 2 ft. 10 in. apart, and 

 measuring 1 ft. 9 in. square at the bottom, and 2 ft. 10 in. square at 

 the top ; these holes were then filled with impermeable earth, and the 

 embankment was laid on them; the seating of the bank was first 

 properly drained and a good outfall provided. Another class of posi- 

 tions in which it is necessary to take especial precautions in forming 

 embankments, is when their feet are exposed to the action of large 

 bodies of water, whether tidal, flowing, or comparatively still, as in 

 lakes. The materials used below the water-line should be of the 

 greatest possible specific gravity, the seat of the bank should be cleared, 

 by dredging, of all loose or compressible mud, and the sides exposed 

 to the wash of the water should be protected by beds of fascines, or by 

 stone pitching in ordinary cases ; in sea water, or in open bays, it may 

 even be necessary to carry the foot of the embankment upon solid 

 masonry walls. [EMBANKMENT ; Kivi:n; WEIH.] 



The earth-works upon most of the principal lines in England have 

 been very heavy, and they seem in some exceptional cases even to have 

 cost 20.000/. or 30,000f. per mile ; nor has it been by any means rare 

 for the average cubical quantity of earth so moved to overage from 

 100,000 to 150,000 yards per mile. In other countries this portion of 

 the cost of railways has been diminished ; first, by reason of the lower 

 prioe of labour ; but secondly and principally, by reason of the facili- 

 ties afforded by the steeper gradients now tolerated. 



There are some minor work* usually included in the description of 

 the excavator's department in the construction of a railway, which are 

 of sufficient importance to require notice. These are the fencing in 

 of the land ; the formation of the cop mound, and of the ditch; the 



planting of the quickset hedge; and the soiling and planting of the 

 slope*, nit as these works may seem to be in themselves, 



much of the stvurity from accidents of the railw.iv .1, |., u,l - upon their 

 being well executed and well maintained ; am! it is es|>ccially on 

 account of habitual disregard the American engineer* display 

 safe enclosure of their lines, that the accidents from strayed animals 

 occur 10 frequently with them. Tin- planting of the slopes ol 

 bankments, it may also bo added, is an easy and profitable mode of 

 ' protecting tin m. 



Bridges are required on railways for the purpose of carrying them 

 across the various water-courses ; for maintaining the i 

 communications either above or below the level of the rails ; or for 

 carrying the roadway above the surface of the ground in deep 

 gorges when for local reasons it is found that the construetioii of 

 viaduct* is preferable to the execution of heavy embankment!. The 

 choice of the materials used for the construction of railway 1 

 must mainly be influenced by economical considerations, always bear- 

 ing in mind the fact that in unJtr- bridges the materials used uhould 

 be of a permanent description ; because the repairs of the substratum, 

 so to speak, of a roadway are always attended with dittiruliy ; for 

 unr bridges wood, brick, stone, or iron may be used as may be found 

 advisable. The reader is referred to the articles BKIM.I and Y 

 for a detailed notice of the principles of construction required to be 

 followed in this class of works, and under SKI;W Audi and TUHMXU 

 will bo found notices of peculiar forms of bridges freqin -ntly 

 employed on railways. It seems that upon the average there are about 

 2} over or under road bridges per mile forward of railway in Engl.ind, 

 i vi n when a considerable number of level crossings are allow 

 England there is at least one crossing per mile. As was before said, 

 the latter should be avoided as much as possible, for they are a fre- 

 quent source of accidents, and the cost of the guardian re 

 interest of a larger sum than an ordinary bridge would cost. It is not 

 often, in fact, that an ordinary over or under bridge costs more than 

 1000/. to 2000/. ; or perhaps, taking into account the approach roads, 

 the latter figure may be taken as an average ; this has to be set against 

 the cost of the cottage, gates, and crossing, and the keeper's way 

 cose a level crossing should be resorted to. It is usual to e.- 

 that the cost of culverts, surface, or underground drains of a railway 

 amounts to 20 per cent, of the cost of the under-bridges ; the cutting of 

 the lateral ditches being carried to the earthworks account. The 

 masonry for lining tunnels, or for retaining walls, forms port of those 

 special items in railway estimates. 



When the various works connected with the cuttings and embank- 

 ments are finished, and the bridges are ready to receive the l>all;,-i . the 

 railway is said to be brought toformniin,i la'il, and all that ivn.. 

 be done is to lay down the permanent way. The formation li 

 usually mode about 2 feet below the intended rails level ; the width 

 of its surface is about 30 feet, exclusive of fences and ditches ; and it 

 is made higher in the centre than at the sides, in order to throw off 

 the rain water. 



'"ting and tatjinif (he permanent way. In the earlier periods of 

 the history of railways very warm discussions were carried on with 

 respect to the form of rail, and the mode of attaching it to the sleepers 

 or blocks ; but at present there seems to be a very marked tendency 

 on the part of engineers to adopt uniformly the system of double- 

 headed rails, keyed to chairs spiked upon cross wooden sleepers, and 

 fish -jointed at the ends. As many useful lessons were learnt in the 

 course of the experiments by which the system now generally adopted 

 was arrived at, and the history of the superstructure of railways is in 

 itself very interesting, a slight notice of the various phases of the 

 discussions in question may be desirable. So much indeed of the 

 commercial success of a railway depends upon the perfection of its 

 permanent way, that it behoves every engineer, at least, to study 

 carefully the phenomena which might have been observed during 

 the respective trials; and it is even desirable that the directors of 

 railway companies should know something of the previously made 

 experiments in this matter so as to avoid a useless repetition of them 

 hereafter. 



When locomotive engines travelling at speeds of even nine miles an 

 hour had been introduced, it was soon found that cast-iron fish-bellied 

 rails were so liable to be displaced and fractured that their use was at 

 once abandoned ; parallel wrought-iron rails were substituted for them 

 universally. On the Liverpool and Manchester, and on nearly all the 

 railways executed by the Stephensons in the early periods of the 

 railway system, the rails were keyed to chairs, fastened to stone blocks 

 bedded in the ballast ; but it was soon found that- the blocks, which 

 were isolated from one another, were exposed to sink unequally, and 

 thus to deform the road ; and moreover that the unyielding nature of 

 the point of support (when it hod once found a bearing) made the 

 roadway very injurious to the carriages and rolling plant. Mr. Locke 

 seems to have been the first to have adopted on a large scale (as the 

 means of obviating these inconveniences) the use of .the old system of 

 wooden sleepers, passing beyond the two rails (as shown on Jig. 10) so 

 as to carry two chairs ; and at the present day this system has been 

 generally adopted wherever the rails are used with only ocen 

 supports. Many essays of cast-iron sleepers have been mode, without 

 success, it must bo added, for in the present state of iron metallurgy 

 cast-iron goods are too brittle to be employed for articles subjected to 



