MOTIVE POWER AND ROLLING STOCK 319 



The weight of the logs may be sufficient to hold them firmly on 

 the bunk without the use of chains; however, if the train is long 

 and the strain is severe, chains are used. Where the cars are 

 equipped with air brakes, extension air-brake hose is adjusted 

 under the log or logs between the two trucks, and is held in 

 place by chain or rope attachments placed around one of the 

 logs. 



Trucks weigh from 10,600 to 13,500 pounds each and have a 

 rated carrying capacity of from 50,000 to 75,000 pounds. 



Fig. 90. — A Log Truck of the Type used in the Pacific Coast Forests. 



In practice low trucks seldom carry more than 5000 feet and 

 high trucks 7500 feet, log scale. 



ROLLING STOCK AND MOTIVE POWER EQUIPMENT 



The number of logging cars required on a given operation is 

 dependent on 



(i) The amount of timber handled daily 



(2) Capacity of the individual cars. 



(3) The average number of cars hauled per train load. 



(4) Manner of loading and handling cars in the woods. When 

 loading is concentrated in one or a few places, fewer cars are 

 required than where loading is done at various points. 



(5) Manner of handling cars at the destination. If the train 

 crew unloads the cars on arrival at destination, the number of 

 cars required is less than where the cars are left to be unloaded 

 while the engine returns to the woods for another train load. 



(6) The distance that the cars must be hauled. On long 

 hauls a maximum number of cars are on the road to or from the 



