200 LOGGING 



which is supported on two sets of trucks, each of which is pivoted. 

 The machine is moved from one set-up to another by means of 

 a locomotive. On arrival at the location where it is to be used, 

 the frame is elevated above the rails by hydrauHc jacks, the 

 trucks turned in a quarter circle, and a short span of track placed 

 under each truck. The machine is then lowered and shunted 

 ofif to one side of the railroad by the side of the head spar tree, 

 where it is blocked up and remains until the next move is made. 

 This leaves the main railroad track clear for the operation of 

 logging trains. 



The steel spar machine operates from the main track and may 

 be either moved about under its own power or hauled on a car 

 by a locomotive. In the first case the skidder is mounted on a 

 steel frame supported on heavy trucks to which power is trans- 

 mitted by a drive chain. In the second case the skidder is 

 mounted on a steel frame which is carried on a set of specially 

 designed flat cars. During operation the machine is elevated 

 above the cars by means of hydraulic jacks, and supported at 

 the corners by blocks. These cars are then pushed to the rear 

 of the machine so that empty log cars can be brought under 

 the forward part of the skidder for loading. 



The three main drums on the skidder are arranged in a row in 

 front of the boiler. The forward drum handles the slack pulling 

 cable, the middle one the outhaul cable and the rear one the 

 skidding line. 



In operation the outhaul and skidding drums are interlocked, 

 and when the outhaul cable is wound on its drum, the trolley is 

 drawn out towards the tail tree, carrying with it the skidding 

 line and the slack pulling line. When the trolley reaches the 

 point at which logs are to be secured the drums are stopped and 

 the interlocking device freed. When the slack pulling line is 

 wound on its drum it operates the slack puller which runs out 

 the slack for the skidding line. The latter is then carried to a log, 

 or logs, which are attached to it by tongs or chokers. Logs can 

 be drawn in a distance of from 60 to 75 feet on either side of the 

 main cable by the attachment of short extensions to the main 

 skidding line. When the logs have been pulled in near the main 



