140 



BULLETIN 711, U. S. DEPARTMENT OF AGEICULTURE. 



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. 



Fig. 48. — Location of equipment and improvements, North Bend system 



Equip'inent. — 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 sj^stem. 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 j^arding 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 coul'd be so designed as to serve for 



