RAILWAY CONSTRUCTION. 205 



bolt had to be turned a very little at a time, one after the other. 

 Independent bolts and nuts, either of iron or steel, are now 

 universally used ; plain holes, with sufficient allowance for work 

 and expansion, being punched or drilled in the rails and fish- 

 plates. 



For many years the depth of the fish-plates continued to be 

 made the same as the space between the upper and lower members 

 of the rail, as shown in Fig. 280 ; but with the heavier loads and 

 higher speeds of our modern railway working it has been found 

 necessary to strengthen the joints by providing deeper or stiffer 

 fish-plates, as shown in Figs. 283, 284, and 285. For bull-head 

 rails the fish-plates have been brought down underneath the 

 lower table, and in some cases extended down sufficiently far to 

 admit of a second set of fish-bolts under the rail. For flange 

 rails some fish-plates are used simply of the form of angle irons, 

 and others have the angle portion carried out beyond the end of 

 the flange, or foot of rail, and then turned down vertically to a 

 depth of an inch or more below the rail. The latter makes a 

 very strong fish-plate. 



Fish-plates, like rails, are now almost universally made of 

 steel. 



The efficiency and durability of a fish-plate depends materi- 

 ally upon its angle of contact with the under side of the head 

 of the rail, and the extent of its contact surface. It would be 

 an error to suppose there is little or no wearing away in fish- 

 plates, as in reality there is very considerable wear, and especially 

 in rails of lighter section. If the under side of the head of rail 

 has a curved outline, as in the rail in Fig. 287, there will be 

 some difficulty in ensuring a perfect fit in the fish-plates ; the 

 curve of the one may not quite correspond to the curve of the 

 other, and the contact surface will be very small. It is better to 

 make these contact surfaces in straight lines, and to a wide 

 angle rather than to an acute angle. In Fig. 288 the under side 

 of head and corresponding top of fish-plates are set at an acute 

 angle, and fish-plates to this pattern will soon wear up to the 

 vertical web of rail, and cause a loose noisy joint. 



In Fig. 284, showing a different type of rail, the contact 

 surfaces are set at a very much wider angle, and will allow much 

 more wear before the fish-plates can work close up to the web of 

 the rail. 



When once the fish-plates are close up to the web, the best 



