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. 
