TRACTION ENGINES 



445 



main axle upon which the drive wheels operate. Although 

 made of a square bar, it is round at the bearing B, and 

 revolves in it. Although the brackets for this type of 

 mounting are attached to the boiler, the boiler itself, 

 being round, is probably strong enough so that the ex- 

 cessive strain will cause very little trouble. This type of 

 mounting very seldom contains springs. 



585. Frame mounting. To remove as much of the 

 strain as possible from the boiler, some engines are now 

 coming upon the market with a frame which supports 

 engine, transmission gears, and boiler. Or else the frame, 

 supports the boiler and the boiler supports the engine. 



FIG. 327 FRAME-MOUNTED VERTICAL TRACTION ENGINE 



Fig. 326 shows the frame for this type of engine with the 

 boiler and transmission gears removed. Fig. 327 shows 



