Comparing: T1 Heavy Tank vs. BDR G1 B vs. KV-1

Development of the T1E2 started in the U.S.A. in May 1940. The vehicle was designed as a heavy tank. The distinctive features of the vehicle were a cast hull and hydromechanical transmission with a double-disc hydraulic converter. Later, the tank was designated M6. A total of 9 vehicles (1 of which was experimental) were produced. The tank never saw action.

The project of a new vehicle was suggested by engineers of the Baudet-Donon-Rousell company in June 1938. However, the design was never developed.

Development started at the end of 1938. A prototype was produced in August 1939. The vehicle first saw combat in December 1939 at the Mannerheim Line. The tank was mass-produced from March 1940 through August 1942, with a total of 2,769 vehicles manufactured.