A replacement option for the T-10 heavy tank, developed in the late 1950s. It was supposed to have enhanced armor and armament and be the first mass-produced tank with the new UTD-45 diesel engine. Eventually, the vehicle could have been armed with a 140 mm gun; however, after the costs for organizing production were assessed, the project was discontinued in favor of modernizing the T-10, as a result of which the T-10M was built.