216 RAILWAY CONSTRUCTION. 



the rails. This arrangement was the same as was then in use 

 on the ordinary wood-sleeper road, where an extra large chair 

 was placed at the rail-joints, and was the most approved method 

 for many years before fish-plates were introduced. The inter- 

 mediate sleepers were shorter, and had only two chairs. 



Fig. 308 represents a long, flat, cast-iron sleeper made in two 

 halves, bolted together just below the under side of rail at each 

 of the three chair-seats. The rail was gripped and held in 

 position without the use of wooden keys. This being a joint 

 sleeper, three chairs were used, as in Fig. 307. Only two chairs 

 were used on the intermediate sleepers. 



Figs. 309 and 310 are somewhat similar, but the circular one 

 is higher and more cup- shaped than the other of oval form. 

 The oval pattern has two small recesses for holding two s nail 

 hard-wood cushions. The circular holes shown in the sides of 

 the sleepers were intended to facilitate the packing, or tamping, 

 of the light sandy ballast. 



Fig. 311 represents a rectangular cast-iron sleeper, as used 

 for the flange rail. The rail rests on cast-iron cross-ribs, bevelled 

 to give the proper cant, and is held in position by the tie-bar 

 bolt and clip-piece, as shown. The small projecting lug, formed 

 on the under side of sleeper, fits into a corresponding notch in 

 the tie-bar, and keeps the sleepers to gauge. The tie-bar passes 

 through the loop end of the same bolt which secures the rail, 

 and is held up tight against the under side of sleeper. 



Figs. 312 and 313, both the same in principle, possessed 

 features which appeared to give great promise. They were 

 simple in construction ; the rail was kept well down, and did 

 not come in contact with the cast-iron at any point. The long 

 wooden wedges, which fitted into the rough or serrated sides of 

 the casting, acted as a cushion to the rail, and were intended 

 to sink deeper into the recess as the super-imposed weight 

 increased, or the wood became thinner from shrinkage. In 

 practice, however, it was found that these sleepers were not the 

 success that was anticipated. 



It was soon observed that sand and fine particles of gravel 

 from the ballast worked their way into the lower part of the 

 recess, and became so compact as to prevent the wooden wedges 

 working further down to increase their grip on the rail. Even 

 when the recess was kept free and clear of sand, the enormous 

 pressure exerted by the wooden wedges broke the iron at A, 



