(under subclass 55) Power apparatus mounted on the frame connecting the axles.
SEE OR SEARCH THIS CLASS, SUBCLASS:
55, for frames carrying a motor or power-plant and mounted by means of springs on both axles or mounted pivotally on the front axle and by springs on the rear axle.
61, for frames carrying a motor or power-plant and mounted pivotally on the rear axle and by springs on the front axle.