36 FOREST UTILIZATION 



The hauling capacity of an engine is : tractive 

 force divided by the sum of the fric- 

 tional and gravity resistance, both ex- 

 pressed in pounds, deducting the weight 

 of the locomotive from the quotient. 

 For example : 



Weight of locomotive on 4 driving wheels 

 = 20,000 pounds. Tractive force is 4,000 

 tons. 



First case Frictional resistance 8 pounds per 

 ton, grade level. Then the hauling ca- 

 pacity equals 4,000 tons over 8 (friction) 

 plus o (gravity) minus 10 = 490 tons. 



4000 



minus 10 = 490 tons. 



8+0 

 Second case Frictional resistance same as 



above, grade i%. 



4000 



minus 10 = 133 tons. 



8+20 



Third case Frictional resistance 8 pounds, 

 grade 2%. 



4000 



minus 10 = 73 tons. 



8+40 



The cost of hauling logs on a standard rail- 

 road, per carload of 40,000 pounds, 

 amounts to $5 for distances of one to 

 fifty miles, and to $6 for distances of 

 fifty to one hundred miles. 

 Porter's catalogue gives the cost of hauling 

 as ranging from 3Oc to 6oc per 1,000 

 b. ft. for a logging distance of from 

 five to ten miles. At Chicora, Ala., 

 two standard trains provide daily, to- 

 gether, 100,000 b. ft., coming from a 

 distance of about eight miles. 

 Small (narrow gauge) locomotives haul from 

 60,000 to 120,000 b. ft. per week over 

 distances of from five to ten miles. 

 Where grades are not excessive, a locomotive 

 should cover daily 60 to 80 miles, the 

 hauling distance varying from 2 to 10 

 miles. 

 G. Mono rail. 



The mono rail portable railway is a French invention 



(Caillet) and has been tried to a limited extent in India. 

 It consists of one rail only, resting on steel sole plates at 

 intervals of a few feet, and is laid down direct on the 

 surface of the ground. Rails are joined together by scab- 

 bard fish plates. The trucks have two low wheels, grooved 



