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قراءة كتاب Motor Truck Logging Methods Engineering Experiment Station Series, Bulletin No. 12
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Motor Truck Logging Methods Engineering Experiment Station Series, Bulletin No. 12
3000 feet, B. M., of Douglas fir, depending upon the locality. In such cases, it is an advantage to have a lighter truck, say one of 31⁄2 tons capacity. By adding additional leaves to the rear springs of a truck of this capacity it may be made to carry a larger load than it would be possible to put on a 5-ton truck and still comply with the law. The pulling power of the 31⁄2-ton truck and the 5-ton truck is practically the same so that the difference in dead weight between the two may be carried in a profitable manner by adding four or five hundred feet B. M. of logs. Another advantage of the lighter weight truck is speed. The 31⁄2-ton truck is geared to make from 14 to 16 miles an hour, while the 5-ton truck is usually limited to from 10 to 12 miles an hour.
Whenever the legal weight limit does not enter into the problem, as in operating over a pole or plank road for the entire distance, it is, of course, advantageous to carry the largest loads possible. In such cases a 5-ton truck with an 81⁄2-ton trailer is the most profitable investment. This allows a much larger load to be carried in proportion to the overhead charges. The disadvantage of the 5-ton truck is that it is very heavy and unless the roads are good, it will easily sink into the ground and cause trouble. A common fault of the 5-ton truck today is the overweight of the front end, which is too heavy for the width of tire on the front wheels. This can be very easily overcome by the use of wider tires.
LIFE AND DEPRECIATION
The life of a truck is directly proportional to the care that it receives, hence, a good driver is a most important consideration. If the right man can be secured his wages should be a secondary consideration.
The charge to be made for the depreciation of a truck is an uncertain question. Some loggers figure on the basis of four and a half years, others on as much as seven years. The depreciation charge on a truck used in the logging industry should depend largely upon the type of road over which it is operated. Loggers in general over-rate the life of their equipment because they do not fully realize the severity of the work. Over a fore and aft plank road or a cement road, where the jar and vibration are reduced to a minimum, the wear and tear on the equipment is very much less than where the truck is operated over a cross-plank road or an unpaved public road. The matter of depreciation, then, will depend largely upon the type of road over which the truck is to operate. In general a four-year depreciation charge less 25% sale value at the end of that time should be used as a basis for figuring costs unless the hauling conditions are very favorable. Only under very rare circumstances should more than four years be allowed. It should be remembered that the depreciation on a truck is very heavy during the first year, and the sale value at the end of a year is only half the original price. Many truck operators now hauling over good roads who are depreciating on the basis of five years say that a four-year depreciation would be more nearly correct. Another factor in favor of a four-year depreciation charge is that methods of logging are changing constantly and that trucks in that time may be improved upon to such an extent that the use of the old equipment would be unprofitable and inefficient.

