3-inch Gun Motor Carriage T40 prototype. This 3-inch self-propelled gun was the rebuilt T24 by Baldwin Locomotive in 1941. The Japanese attack caused this model to be accepted for production, however, the project was terminated in April 1942. The Tank Destroyer Board felt that the vehicle was too slow and the M1918 gun was not available in quantity. T24 Gun Motor Carriage The U.S. Army expressed a need for a vehicle capable of stopping and destroying enemy tanks. The new vehicle, dubbed the "Tank Destroyer", would have the same armor protection and general mobility of a standard tank, but would be heavily armed with enough punch to decimate enemy armored formations. Up until 1941, the only vehicles available were modified trucks and half-tracks, which lacked greatly in the mobility, firepower and armor departments. During the summer of 1941, Baldwin Locomotive Works began development of a vehicle to fill the need for a true tank destroyer. They began with the chassis of...