The trailer is coupled to the truck by a reach which is passed through guides secured to the hounds of the trailer. The latter may slide upon the reach and is held in the desired position with reference to the truck by means of clamps. The hounds are located fore and aft of the axle and are connected to it by steel plates. The square reach is more favored generally by loggers than the round type for the reason that it can be more easily adjusted, particularly the round reach that is cut in the woods, which is irregular and has to be clamped very tightly in order to make it stay in place. Holes bored through the square reach makes the adjustment easy. Combination steel and wood reaches, the sides being of channel iron and the center of wood, are favored by some operators. The twin bunks of the trailer carry the load in balance upon the axle independent of the reach, thereby relieving the reach of all vertical stress. (See illustration below). The rear bunk is just an ordinary wooden affair designed only to help support the weight of the logs. The front bunk is of the same construction as the one on the truck (described above) and serves to hold the load in place. [Illustration: Type of trailer adapted for heavy Pacific coast logging.] The trailer is guided through the reach directly to the axles, thus relieving the springs and frame from side stresses. The springs and their suspension from the frame permit a limited movement of the frame and the load independent of the wheels and axles and vice versa. This enables the wheels to pass over an obstruction or drop into a hole without subjecting the trailer to shocks that would otherwise ensue. Other types of trailers are used to a limited extent. The trailer described above was evolved by local engineers and is in almost universal use in motor truck logging operations.