LOGGING IF THE DOUGLAS FIR REGION. 



137 



In 1911 a logging engine with four drums was built especially for 

 use with this system. The main drum is driven through a compound 

 train of gears by an internal gear, which revolves it in the same direc- 

 tion as the trip drum. The trip drum is a high-speed drum, which 

 insures the quick return of the carriage. In front of these two drums 

 are located the haul-in and straw-line drums. All the drums take 

 the lead of the line on top. 



The operating levers are conveniently located. The three princi- 

 pal drums are equipped with steam frictions, the throttles of which 

 are banked in front of the engineer's position, immediately below 

 the main throttle. The brake operating levers are mounted on the 

 frame, within easy reach of the engineer's left hand. 



The main and trip drums are each provided with powerful steam- 

 operated brakes. The enginer controls the pressure exerted by the 

 brake through the valve of the brake cylinder. The operating lever 

 is connected to both the valve stem and cross head. When the lever 

 is moved to any position opening the valve, the travel of the cross- 

 head automatically closes the valve when the desired tension is 

 reached. This forms a flexible control. The engine is mounted on a 

 sled. The cylinders are 11 by 13 inch. The boiler, which is of the 

 oblong fire-box type, is 66 inches in diameter. This engine costs about 

 $9,000 f. o. b. Portland: 



The length and diameter of the lines used with this system depend 

 on the distance between the main cable supports and the size of the 

 timber. As a rule the main cable ranges from 1^ to If inches in diam- 

 eter. The haul-in and haul-back cables are generally seven-eighths 

 of an inch in diameter. Wlien the main cable is 11 inches it generally 

 leads direct to the main cable drum on the engine. If one of larger 

 diameter is used it may be necessary to use a purchase line to in- 

 crease the power of the engine. Under such conditions a block is at- 

 tached to the main cable. The purchase line, leading from the main- 

 line drum, passes through this block and then down to a stump be- 

 tween the head tree and the engine, where it is fastened. 



One company hauling second-growth timber down a steep moun- 

 tain side used the following lines : 



Lines. 



Type of 

 construc- 

 tion. 



Diame- 

 ter. 



Length. 





6 by 19 

 6 by 19 

 6 by 19 

 6 by 19 

 8 by 19 

 8 by 19 



Inch. 

 U 



a 

 l| 

 H 



Fccf. 

 1,800 



Haul-in line 



2.000 



Haul-back Unc 



4,000 



Straw line . 



4,000 



CholTers 



20 to 30 





4,000 







1 Includes a set of gays for tho tr.il tree. 



Note.— The selUng price of wire rope is discussed under ''Ground Yarding." 



