58 
BULLETIN 711, IT. 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 
