917 



RAILWAY. 



RAILWAY. 



918 



the peculiar actions to which sleepers are forcedly exposed ; but it is 

 still to be hoped that means may be discovered by which this objection 

 may be removed, and that this material, inattackable by insects and 

 comparatively indestructible by atmospheric influences, may be sub- 

 stituted for wood. The rapid decay of the wooden sleepers has, 



Fig. 10. 



indeed, been always the subject of anxiety to railway engineers ; and 

 many patents have been taken out for their preservation. Sleepers 

 have been soaked in solutions of zinc, copper, mercury, &c., with vari- 

 able success ; but at the present day it seems to be generally admitted 

 that creasote is the material which, when properly applied, contributes 

 the most valuable properties to wood so exposed; all these pro- 

 cesses are however but palliations of a serious evil inherent to the use 

 of wood, and it certainly would be preferable to employ a material 

 exempt from the conditions of decay above enumerated. However 

 this be, the cast-iron chairs used either for blocks or for sleepers are 

 spiked down with iron spikes, and some trifling modifications of the 

 patterns of the chairs are at times advantageously made in order to 

 avoid the splitting of the fibres of the wood. The rails are fastened 

 to the chairs by means of compressed wooden wedges, which naturally 

 expand again when exposed to the effects of moisture ; these wedges 

 are at the present day creasoted on the best lines of railway. Sleepers 

 are usually from 7 to 9 feet long, by 10 in. by 5 in. , and are usually placed 

 at distances of 3 feet from centre to centre, on the average ; especially 

 on the lines where heavy locomotives are used. 



The sleepers, as was said, are laid in ballast, which should as far as 

 possible consist of gravelly sand, sufficiently permeable by water to 

 allow the rain to pass rapidly into the surface, and to the side drains. 

 When, however, ballast of this description cannot be obtained, it may 

 be replaced by sand, by shingle, by broken stones of not more than 24 

 inches in diameter, by burnt clay, or by a mixture of chalk and flints ; 

 in mining districts forge ashes and broken slag are advantageously 

 used. The ballast is made (for double roads) 30 feet wide and 18 

 inches thick, on the average ; and its surface is dressed off so as to 

 form a series of water-courses. It requires about 8,800 yards cube of 

 ballast per mile forward of railways, or about 6 yards cube per yard 

 lineal. 



The form of rail used, and its weight, have passed through many 

 changes, but they have finally resolved themselves into two principal 

 varieties, known as the double-headed rail, and the bridge rail ; the 

 latter being employed on lines such as the Great Western, where 

 longitudinal bearings have been adopted instead of the 

 ordinary chairs and sleepers. The advantages and disadvantages of 

 the bridge rail will be discussed hereafter, and for the present, attention 

 will simply be called to the steps which have led to the adoption of 

 the double-headed rail most frequently employed. 



In figure 11, the illustration marked.a, represents the section of the 



Fig. 11. 



railway just mentioned by the form shown on k ; and at I is shown a 

 contrivance for keeping the rail hi its seat. The double-headed rail 

 may be considered to have been introduced by Mr. Locke, who used it 

 on the Grand Junction and the South Western lines in the form showu 

 at k ; and eventually, notwithstanding the other modifications of the 

 rail with intermediate supports as at m, Mr. Locke's form has been 

 generally adopted. At g, n, and o, are represented the manners of 

 'orming the end joints of the rails, either with a half lap, or with butt 

 ends, the system now prevalent ; and at I is shown a rail of a peculiar 

 section designed to fit more closely to the tires of the wheel. At the 

 present day, however, little attention is paid to this theoretical 

 perfection of the roadway, and the upper and lower surfaces of the rails 

 ire made identically the same. When firstly the double-headed rails 

 were introduced they were made in 15 or 16 feet lengths, of about 

 56 Ibs. weight per yard forward ; at the present day they are made nf 

 Torn 70 to 80 Ibs. per yard, and are often of 21 feet length. The cast- 

 iron chairs have also been increased in weight, and instead of weighing 

 'or the joint chairs 20 Ibs., and for the middle 15 Ibs. each, they now 

 weigh for the joint chairs 38 Ibs., and for the middles 21^ Ibs. each. 

 Latterly when the rails have been fish-jointed, or made with fish plates 

 weighing about 28 Ibs. per pair bolted on the respective sides of the 

 rail, the middle chairs only are employed, and the sleepers at the end 

 of each rail are brought as closely to the fish joint as possible. 



When Mr. Brunei attempted to introduce the broad gauge he also 

 attempted to introduce the American system of placing the rail with 

 a continuous bearing, and thus was led to adopt the form o rails 

 represented by p, j, r, and on fy. 12, partly with the hope 



Fig. 12. 



fish-bellied rail used on the Manchester and Liverpool line ; 1 is the 

 same rail fixed in its chair ; c and d are representations of a rail of the 

 same form used on the Newcastle and Carlisle railway; these rails 

 were all fastened with iron keys. On the London and Birmingham 

 railway Robert Stephenson introduced a moditication of this system 

 represented by c and /; this rail was partially replaced on the line of 



of being able to diminish the weight of iron. He began to use 

 rails weighing about 45 to 47 Ibs. per yard, and they were bolted or 

 spoked to the longitudinal baulks at distances of about 18 inches ; but 

 the continually increasing weight of the locomotives, and the increased 

 rate of travelling, have forced the parties who have used the bridge 

 rail to follow the example of the advocates of the double-headed one ; 

 so that at the present day the bridge rails are often made of even 90 Ibs. 

 weight per yard forward. The great objection to their use lies, however, 

 in the necessity they involve for a very expensive timber substructure, 

 which is liable to rapid decay, and to frequent deformations by the 

 warping of the wood, or by the expansion of the rails. Practically, 

 theu, although the system of continuous bearings produces a road of a 

 very pleasant description for the traveller, so long at least as it is in 

 order, it is found to be of so costly a maintenance that it is rarely 

 used in England, unless when the roadway has to be carried over 

 viaducts, bridges, or other works, where the percussion upon the 

 intermediate bearings might become injurious. 



It may be 'as well here to observe, that in laying rails, the allowance 

 for the elongation produced by summer heat must be very carefully 

 made. In a 15 feet rail, the difference of length for an increase of 76 

 Fahr. will be about T \th of an inch ; but at the same time that pro- 

 vision must be made for the free expansion of the rails, they must not 

 be laid with so open a joint as to give rise to concussions. It is usual, 

 also, to give a slight inclination to the upper surface of the rails, 

 inclining inward about 1 in 30, for the purpose of giving a better 

 bearing to the conical surfaces of the wheels ; and in curves, the outer 

 rail is elevated above the inner one, by a height regulated by the maxi- 

 mum velocity attained upon the curve, and by its radius. Upon level 

 crossings, very sharp curves, viaducts, or bridges, it is usual to fasten 

 counter-rails ; but they have so often proved sources of danger, through 

 their independent movements, that these counter-rails are never placed 

 unless under very exceptional circumstances. On level crossings they 

 are necessary in order to protect the rails from the shocks of passing 

 waggons. A very common elevation of the outer rails, on curves of 

 1000 yards radius (and this seems to be the minimum radius which 

 should be allowed in railways upon which ordinary express speeds are 

 attained) is about 2 inches ; and in curves near stations, of 600 yards 

 radius, the elevation becomes about 2$ inches. Fractures of the rails 

 occur on changes of temperature, and chairs are frequently broken 

 when wedged up too tightly. Great care is therefore required in the 

 inspection of the rails at these seasons ; and it is worthy of remark, 

 that there is a marked tendency of the rails to displace themselves in 

 the direction of the movement of the trains, especially on inclines and 

 near the stations. In some cases, every 10th or 20th rail is notched 

 upon it* chairs, in order to resist the tendency to this kind of 

 displacement. 



The battle of the gauges, which raged so f uiiously a few years since, 

 has now been practically solved by the adoption of the mixed gauge on 

 the Great Western line itself ; and indeed the advantages of a uniformity 

 of gauge are so much greater than those which can be secured even by 

 a more logical arrangement than the one adopted originally by Mr. 

 Stephenson, that it is almost idle to discuss the question at present. 

 For all useful purposes, it is ascertained that the i feet 84 mclics 



