TM 9-721 Heavy Tanks; M6 and M6A1 Operations and Maintenance (Manufactured by Baldwin Locomotive Works) Heavy Tanks M6 and M6A1; Armored, full track laying vehicles, each powered by an aviation-type; radial, 9-cylinder, air-cooled gasoline engine. On 14 December 1944 the M6 was declared obsolete. Only forty units were produced and they never left US soil. Several toured the United States for propaganda purposes, where they gave performance displays (such as car crushing) at War Bond drives and the like. All were eventually scrapped except for a single T1E1 which is on display at the United States Army Ordnance Museum, Aberdeen, Maryland (?) Variants T1 - Cast hull, hydramatic transmission. Never built. T1E1 - Cast hull, electric transmission. Often unofficially referred to as M6A2. 20 units built. T1E2 / M6 - Cast hull, torque converter transmission. 8 units built. T1E3 / M6A1 - Welded hull, torque converter transmission. 12 units built. T1E4 - Welded hull, hydramatic transmission. Never built. M6A2E1 - Uparmored T1E1 with a new turret armed with a T5E1 105 mm gun. Never built. 1943