TRACTION ENGINES 453 



proper width of tires at the factory. But where an en- 

 gine is to be used for job threshing a part of the time 

 and for plowing a part of the time the wheels should be 

 made so an extra width of tire can be attached to support 

 the engine for plowing. 



592. Road rollers. For road rolling purposes traction 

 engines as a rule, especially the gearing and bearings, are 

 made much heavier. The tires are wider, and the front 

 truck instead of being made of two wheels is made into 

 one broad wheel. 



HANDLING A TRACTION ENGINE 



593. Moving an engine. When moving an engine it is 

 best to carry more water than when doing stationary 

 work. This is especially true in hilly fields or hilly 

 roads. The gauge glass and water cocks should be care- 

 fully watched. The steam pressure should be maintained 

 near the blow-off point. Upon approaching a hill judg- 

 ment should be exercised in regard to the fire and amount 

 of water and pressure. As much water should be car- 

 ried as is permissible without priming. If possible there 

 should be sufficient fire when starting up a hill to carry 

 the engine to the top. Judgment should also be exercised 

 in regard to the speed. Taking an engine up a hill too 

 fast is apt to cause priming. Also there is danger of 

 reducing the steam pressure so that a stop will have to 

 be made to raise it. When the summit of the hill has 

 been reached, the fire can be started up, more water put 

 in the boiler, and the engine allowed to travel faster. 

 As much and probably more care should be exercised 

 in descending a hill than in ascending. If possible the 

 engine should be taken from the top of the hill to the 

 foot without a stop. If this is not possible turn the en- 

 gine around so that it sits as near level as possible while 



