English: A Killen-Strait caterpillar tractor, probably at Woormwood Scrubs on 30 June 1915, where Thomas Gerard Hetherington demonstrated the vehicle's capabilities to Winston Churchill and David Lloyd George, a step in the adoption of tracks in the development of the tank.
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Captions
Demonstration of a Killen-Strait caterpillar tractor in 1915
Uploaded a work by Albert Gerald Stern from https://archive.org/details/tankslogbookofpi00ster/page/n53/mode/2up Tanks, 1914-1918; the log-book of a pioneer (1919): image opposite p. 33 with UploadWizard