58 BULLETIN 111, U. S. DEPARTMENT OF AGRICULTURE. 



The present ground logging engine consists of an upright boiler, 

 two horizontal engines, two main drums, and usually a third small 

 drum, mounted on a steel frame, all of which, in turn, are mounted 

 on a wooden sled. (Fig, 14.) The large drums may be placed tan- 

 dem, one carrying the hauling line and the other the return line. 

 The third drum carries the straw line, which is used to run out 

 the return or trip line, either when a new setting is being made or 

 when roads are being changed. The engines are classified as simple 

 and compound geared. They are further classified as yarding, swing- 

 ing, or roading engines. An engine having the gears compounded is 

 always classed as a yarding engine. One of the simple geared type 

 is known as a yarding, swinging, or roading engine. The roading 



Fig. 15. — Location of improvements and equipment in ground logging. 



engine has a larger drum capacity than the yarding or swinging 

 engine. In effect, the swinging engine, an intermediate type, is a 

 roading engine, except that it does not have such a large drum 

 capacity. 



The ground type of logging engine is brought to the site on a 

 flat car and unloaded by means of cables and blocks, power for the 

 latter step being furnished by the engine itself. High-lead and 

 overhead engines, as a rule, are mounted on cars instead of sleds, 

 and are transported from one setting to another by their own power 

 or by a locomotive. Where railroads are not used in connection with 



