The one and only HT-340, International Harvester paired a gas turbine engine with hydrostatic transmission. The turbine engine was similar to the turbo-prop engine used in some aircraft, but much smaller. The engine weighed only 60 lbs. It had a speed of 57,000 rpm and required much reduction gearing to drive the hydraulic pump. The pump, in turn, drove a hydraulic motor which propelled the tractor. The first public showing of this unit was at the Nebraska Power and Safety Day in Lincoln in 1961. The tractor now is on display at the Smithsonian Institution in Washington, DC.