Holt tractor

US agricultural tractor using a ‘caterpillar’ track instead of wheels. Holt tractors were deployed in World War I to haul guns and other heavy loads and inspired the development of the tank.

The track system had been invented by the Hornsby company of Grantham, England, 1908, and in 1909 they submitted a tracked tractor to the British Army. It won a prize for its performance, but the Army did not purchase any. Finding no commercial demand for the idea in Britain, Hornsby sold the patents to the Holt Tractor Company of Stockton, California, which had considerable success with the design in the Midwest farming states of the USA. It was the sight of a Holt tractor which inspired Col Swinton to develop what eventually became the tank.