appeared in the mid-1930s to plow highways on a more frequent basis. To combat this a new concept of a single machine able to switch from truck to tractor with the push of a lever appeared in 1938, known as the C5 or later trademarked term "CATRUK", but management and war priorities limited its development and it was abandoned after World War II. This machine was built in a cab-over configuration, front wheel drive, and a hydraulically lowered dual-wheeled tag-axle that would push the tracks up off the ground. "HAFTRAK" is another Linn trademark. References External links The Linn Tractor History of Linn Manufacturing Corp Tractors Half-tracks