FOREST UTILIZATION 31 



bination of upright and horizontal, concentrating weight on the 

 driving wheels and preventing water and fuel from dropping 

 back from the pipes on steep grades. Engines are said to be 

 able to climb 30% grades and to climb over logs, brush, stone 

 etc. Front wheel is for steering only, with front drum for 

 skidding logs by wire cable. 



Pole roads. A statistic of 1886 finds in the United States over 

 2,000 miles of pole roads, using over 400 locomotives and over 

 5,coo trucks. 



I. The rails are made of straight, preferably coniferous poles, 



sufficiently trimmed to fit the double flange of the truck 



wheels. On suitable soil no ties are required, the rail 



being gradually pressed into the ground. 



Saw-n rails, preferably consisting of several layers of 



boards, must be used in curves of the pole road and are 



still largely used near mills on steep and short grades. 



II. Trucks. The wheels should not turn with the axle. An 



oval concave rim said to be inferior to a flat rim with 



heavy flanges. 



Each wheel has about 2 inches room for side play. The 

 reach should turn like a swivel in hind and ffont 

 set, allowing all wheels to stay on the track. 

 III. All lumbermen now agree that pole roads are impracticable, 

 for locomotives. On sawn rails locomotives are still 

 used, however, when prices of steel are high, grade 

 steep, distance short and use intended for a short while 

 only. Sawn wooden rails do not allow of heavy loads 

 and, consequently, seem unadvisable just for logging 

 by steam engines. 

 Forest railroads. 



I. Portable forest railroads. 



In American lumbering portable railroads are little used. 

 The sections of which portable railroads consist are 

 necessarily light and, consequently, unfit for the heavy 

 traffic of American lumbering. In Europe the sections 

 are usually 6 l / 2 feet long, have 2^/2 feet gauge and 

 weigh 80 pounds. Steel ties are preferable at the ends 

 so as to have- the joints supported by ties. The sec- 

 tions are joined by a hook arrangement without being 

 bolted together. 



Usually the sections are merely laid on wood reads. Mo- 

 tive power is supplied by gravity, men or horses. Wheel 

 flanges usually on both sides of the rail. Rail sections 

 of trapeze form are sometimes used in building curves. 

 Bridge switches are preferable to split switches. 

 In the wood yard at Biltmore sections of wooden rails 

 were used, the ties being replaced by iron rods. The 



