A typical incline is successfully operated by the Meickeljohn, Brown Logging Company near Monroe, Washington. It is fifteen hundred feet long and the steepest grade is twenty-eight per cent. An 11-in. × 14-in. roader donkey located at the top of the incline snubs the loads down and hauls up the empty trucks. A one and one-eighth inch wire cable is thrown around the logs and made fast by means of a clevis. This holds the truck and prevents the logs from slipping forward and injuring the driver. On all inclines, the line should be choked around the logs rather than simply attached to the truck to prevent them from slipping ahead.
The snubbing device consists of an ordinary donkey engine fitted with a hand brake of extra large size and special air valves so that air is sucked into the cylinders and let out of the exhaust when the engine is being pulled backwards by the weight of the load. The load is controlled by the amount of air let out of the valves. The braking action is very positive and the load can be stopped in a few revolutions of the crank shaft.
The average time to lower the load down the incline is three and a half minutes. At the bottom of the incline, the cable is released and the truck goes on its way. The cable is attached to the waiting truck by means of a ring fastened to the frame and the donkey pulls the empty truck to the top. The time taken to raise the trucks is three minutes.
On grades too steep to operate a truck safely with the ordinary brakes and yet not steep enough to warrant the expense of the donkey snubber, the difficulty is overcome by means of a friction snubber. This consists simply of a cable which is hooked to the truck and extends through a system of three or four pulleys and thence on down the track. The friction of this line dragging on the ground and passing through the pulleys is enough to hold the load so that the truck engine must exert power to pull the load down the grade. The line is made long enough so that as the load reaches the bottom of the grade, the free end of the cable has been pulled up to the system of pulleys and is ready to be attached to the next load. This system is efficient for small grades, is inexpensive to install, and requires no further attention.
By the use of the incline with the donkey engine snubber, very heavy grades can be taken. The construction of the incline is the same as the rest of the road and is only slightly more expensive to build because of the inconvenience of laying it on such a steep slope. The use of the incline will not slow up the operation to any great extent as from fifty to seventy thousand feet of logs (which is about the average yarding and loading capacity of one motor-truck side), can be taken over it in a day. This method of hauling down steep grades is used in several operations and has been found to be entirely successful.
YARDING
A variety of methods are used by motor truck loggers to get the logs to the landing to be loaded. The larger operations invariably use the high-lead method of yarding as the logs come in quicker and with fewer hang-ups. In a few places the old ground method of yarding with a bull block is still used. The horse team and skid road is used in a small timber where poles and piling are being marketed. The latter is a slow method but will keep one truck busy and is still used in some places where small stands are located along the highway or in other readily accessible places.