224 



LOGGING 



chokers to a traveling block that ran on the main cable. The 

 load descended by gravity, its speed being controlled by a f -inch 

 trip line which was wound on a drum on the engine and then ran 

 up the slope to the head of the tramway where it passed through 

 a pulley fastened to a tree. The line was then attached to the 

 rear of the traveling block. The trip line was held in position 

 by several blocks placed at suitable intervals on the slope. This 

 line also served to return the block to the head of the tramway. 

 In case of a break in the machinery or of the load becoming 

 unmanageable the main cable could be dropped to the ground 

 and the load stopped. 



Adapted from The Timberman. 

 Fig. 6o. — A Single-wire Tramway used in the Pacific Coast Forests. The details 

 of the trolley and the method of attaching logs to it are shown in the enlarged 

 cut. 



A system of this character may be used for distances of 3000 

 feet when there are no pronounced elevations between the two 

 ends of the tram. 



Logs containing from 5000 to 6000 feet, log scale, have been suc- 

 cessfully handled. The hourly capacity of this tramway was 

 12,000 feet, log scale, when the logs averaged from 300 to 500 

 feet, log scale. Three men were required to operate the tram. 



A single-wire gravity tramway used in the West is described 

 in The Timberman, April, 191 2. A i|-inch main cable 2100 

 feet long is suspended between a tree on the upper slope and one 



