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devices. One type has a small drum placed on one end of the 
main drum shaft and a trip line from a yarding engine wrapped 
two or three times around it. When the main cable is to be 
wound up, the trip line is tightened by sheave pulleys, and, as it 
is wound in, the main drum is rotated. 
Another method is to use a donkey engine equipped with 
a large drum and l|-inch cable with the cars attached to the 
free end. The speed is controlled chiefly through the car brakes 
supplemented by friction brakes on the drum. Empties are 
brought to the head of the incline by winding in the main cable. 
Fig. 113. — A Hydraulic Snubbing Machine, a, side view, h, top view. 
Hydraulic machines,^ of the type shown in Fig. 113a and 6, 
have been used in the Northwest to control the speed of cars 
lowered on inclines. 
The water cylinders (K) are closed at both ends and are con- 
nected with the pipe (L) which has a plug valve (M) near the 
middle. When (M) is closed the water is confined and holds the 
pistons (H) rigidly in place. Opening the valve (M) allows 
the water to pass alternately from one end of the cylinder to the 
other, the speed being governed by the extent to which the valve 
1 See The Timberman, Portland, Oregon, October, 1909, p. 51. 
