Abstract: A tractor having a pair of endless, segmented, high drive tracks includes a side boom and a side-mounted counterweight. Boom angle is controlled by a boom winch with a load winch provided for lifting a load. Both winches are hydraulically driven and provide positive drive in raising and lowering. A boom automatic stop arrangement detects full-up boom position and actuates a release valve for dumping hydraulic pressure and preventing further retraction of the boom. The counterweight is pivotally coupled to the tractor by means of a support frame which provides for outward and upward as well as downward and inward displacement of the counterweight over an arc-like path to compensate for boom inclination and the weight of a load.