2i8 RAILWAY CONSTRUCTION. 



During the last few years very many types of wrought-iron 

 and steel sleepers have been introduced, and nearly all of them 

 of the transverse-sleeper pattern, formed out of rolled plates; 

 the sides, and in some cases the ends also, are bent, or turned 

 down to obtain a hold in the ballast. Where bull-head or double- 

 head rails are used, cast-iron chairs, or wrought-iron bracket 

 chairs, are bolted, or otherwise secured to the upper surface of 

 the sleeper, a layer of felt, tarred paper, or other soft material 

 being placed between the two metal surfaces. Where flange 

 rails are used, they are fastened to the sleepers either by bolts, 

 clamps, or clips raised up out of the iron sleeper, and bent over 

 to hold tightening keys. Rolled transverse sleepers can readily 

 be bent, or set in the centre to give the proper cant at the rail- 

 seat ; and in some types the sleepers are pressed in the machines, 

 so as to be narrower towards the centre, and with a deeper turn- 

 over, to obtain increased stiffness. 



In Figs. 314 to 319 are shown some of the patterns which 

 have been brought out, laid down in actual practice, and in use 

 at the present time. 



From the fact that wrought-iron and steel sleepers have been 

 laid down in so many places where cast-iron sleepers were 

 discarded or refused a trial, it is evident that the former are 

 considered to have qualities which the latter did not possess. 

 Rolled iron or steel sleepers are coming more and more into 

 use, especially on foreign or colonial railways. So long, how- 

 ever, as good, well-creosoted timber sleepers can be obtained for 

 our home railways at prices from 3s. 8d. to 4s. 8d. each, and last 

 from fourteen to twenty years, there is little probability that 

 they will be supplanted by iron sleepers at double the cost. 

 But abroad the circumstances of cost and durability are different, 

 and there the rolled iron or steel sleepers, which will outlive 

 two or three sets of wooden ones, must claim advantages which 

 cannot be overlooked. The difficulty will be in the fastenings, 

 the mode of attaching the rails to the sleepers. The constant 

 hammering of metal upon metal, resulting from the vibrations 

 of every passing load, will quickly wear or loosen bolts, rivets, 

 or wedges, and the fastenings which will prove the most efficient 

 will be those that are the simplest and most readily adjusted. 



Fastenings. Figs. 320 to 335 illustrate some types of the 

 principal fastenings used in connection with the chair road, and 

 with flat-bottomed or flange rails. 



