[Illustration: Fig. 28. Log Train, Humboldt County, California.]
In loading, the machine is located so that the empty car will be directly in front of it, and then the logs are lifted up and placed on the car by the derrick. When the car is loaded the machine can either move on to the next car, or pull it under itself into place. With the help of four men it can load from 125,000 to 150,000 feet of timber in a day. By means of the cable it can make up a train, and then by lowering the truck and raising the legs out of the way, it is converted into a locomotive and hauls the train away to the mill or railway station at the rate of three or four miles at hour.
As forests are cut away along the water courses, railways have to be resorted to more and more, Fig. 28. This has had a stimulative effect on the logging business, for now the logger is independent of the snow. On account of the steep grades and sharp curves often necessary in logging railways, a geared locomotive is sometimes used, Fig. 29. It can haul a train of twenty loaded cars up a twelve per cent grade. The geared engine has also been used as a substitute for cable power, in "yarding" operations. The "turns" of logs are drawn over the ground between the rails, being fastened to the rear of the engine by hook and cable. This has proved to be a very economical use of power and plant.
[Illustration: Fig. 29. Donkey Engine Yarding.]
[Illustration: Fig. 30. Giant Raft. In the background is a completed raft; in the foreground a cradle in which a raft is being built.]
Another method of traction where the woodland is open enough is with a traction engine. The ones employed have sixty to one hundred horse power. The great logs may be placed on wood rollers, as a house is when moved, or the logs may be hauled in on a low truck with broad wheels. The "tractor" hauls the log direct to the railway if the distance is not too great.
[Illustration: Fig. 31. Snow Locomotive. Takes the place of 12 teamsters and 12 horses. Minnesota.]
In Northern Michigan a "snow locomotive," Fig. 31, is coming into use, which has tremendous tractive power, hauling one hundred to one hundred fifty tons of lumber over snow or ice. It moves on runners, but there is between them a large cylinder armed with teeth. This cylinder can be raised or lowered by the operator as it moves over the surface of the ground. The teeth catch in the snow or ice, and since the cylinder is heated by the exhaust steam, it melts and packs the snow for the trucks following it. The drum is six feet in diameter, with walls an inch and a half thick, and it weighs seven tons. It is used in all sorts of places where horses cannot go, as in swamps, and by substituting wheels for runners it has even been used on sand.