LOGGING IN THE DOUGLAS FIR REGION. 



83 



On tandem-drum engines the most convenient location is on an exten- 

 sion of the main drum shaft. It is a narrow drum of relatively large 

 diameter, which, having its own friction and brake, can be operated 

 independently of the main drum. The cost of equipping an engine 

 with this device amounts to about $150. 



Oil-burner equipment. — The approximate cost of full equipment 

 for burning crude oil on yarding and roading engines and skidders 

 is about $450 for each machine; on loading engines, about $375. 

 These prices include the tank on the sled, which is used for the 

 storage of both oil and water. The cost of maintenance of this 

 equipment is about $25 per year. 



The oil is hauled from the storage tank to the tank on the rear end 

 of the sled in tank cars, which have a capacity of about 7,000 gallons, 

 and cost about $1,000. 



A large steel storage tank is erected at a convenient point on the 

 logging railroad to receive oil in bulk. The 

 cost of a 200,000-gallon steel storage tank, 

 together with an 8-inch pipe and valves 

 for filling, amounts to about $4,000. 



Electric signals. — Until very recently 

 signals were universally given by means of 

 a light wire attached to the whistle lever, 

 the wire, either solid or twisted, being- 

 strung taut along the outer edge of the run 

 from the engine to the rear of the chance. 

 A solid signal wire costs about $3 ; a twisted 

 one, about $10. 



A large number of operators now use an 

 electrical device which is connected with the 

 lever of the whistle. The current is carried 

 to the woods' end through insulated wires, which can be laid upon 

 the ground or carried upon supports, as desired. Relays of push 

 buttons along the line make it possible to give the signals at any 

 point. Power to operate the whistle is furnished by from 6 to 12 dry 

 batteries. The signal itself is the same as with the old method, and 

 can be heard by the yarding crew, who thus know that the proper 

 signal has been given to the engineer. The device eliminates the 

 trouble of keeping a taut signal wire. It is claimed that the signals 

 are transmitted more promptly than by the old method. One man- 

 ager who is using the electric signal and who has a reputation for 

 conservatism considers the device a " safety-first " appliance. Un- 

 doubtedly it will be universally used in the near future. The device 

 complete for a yarding engine costs about $100. 



Blocks. — Figures 19, 20, 22, 27, and 33 indicate the types of blocks 

 used in general yarding. A number of companies manufacture 



Fig. 33. — Moving block. 



