140 BULLETIN 111, U. S. DEPARTMENT OF AGRICULTURE. 
is always used when the engine makes it possible. To relieve the 
engine of as much of the load as possible, a block purchase is used 
in tightening the line. The standing cable, as suggested by its name, 
is not raised or lowered when the system is in operation. Obviously, 
however, this could be done if conditions warranted. The haul-in 
line is attached to the carriage. In the bight of this line, between 
the carriage and head tree, a butt chain lead block is hung. To this 
block the load is attached. The haul-back line is run out along the 
strip from 100 to 150 feet from the standing line, in the same man- 
ner as in ground yarding, and attached to the carriage. This line is 
used, in connection with a properly located lead block, to draw to any 
desired point the block to which the load is to be attached. The 
layout is shown in figure 48. 
^TkffEE Shea ve 7>ee J a vr 
K 2¥^t/-AuT0-LUBRlCATfNG5Kr-L/HE BLOCK 
t^N.AuTQjMBRICATING SKT-UNE BZCCX 
Fig. 48. — Location of equipment and improvements, North Bend system. 
Equipment. — The equipment is practically the same as that used 
in the MacFarlane sky-line system. 
An ordinary two-drum yarding engine may be used to furnish the 
power for this system. Mr. Vinnedge used a standard 11 by 13 inch 
compound-geared yarding engine with the first installation, securing 
very satisfactory results. To get the best results, however, an en- 
gine differing somewhat from the standard ground yarding engine 
should be used. An engine designed especially for use with the Mac- 
Farlane system fulfills the requirements nicely. 
One operator, after convincing himself that this system would log 
parts of his holdings cheaper than a ground machine, decided that 
the best results would be secured with a special engine. He thought, 
however, that this special engine could be so designed as to serve for 
