Work on a replacement for the T-54 began at the Nizhniy Tagil tank plant in the early 1950s. The tank, designated Object 140, was very similar to the T-54 in overall design but improved in almost every detail. The new main armament was the D-54TS gun, much more powerful than the D-10T seen on the T-54. Armor was strengthened by increasing the upper front plate angle and installing a more rounded turret. Roadwheels became smaller in diameter and made of aluminium to improve driving smoothness; the main gearbox was changed to an epicyclic type to enhance driver ergonomics. Overall mass was kept the same by using bent side armor and installing the engine at an angled position. By 1958, two test tanks were produced, but it was soon recognised that the Object 140 had serious design flaws which made the engine and transmission much more difficult to repair than the T-54's due to their cramped position. As a result, lead designer L.N. Kartsev decided to close the project. One Object 140 is now displayed at the tank museum in Nizhniy Tagil.

Introduced in Update "Firebirds", the Object 140's D-54TS gun can penetrate any opponent frontally with its APHE shell at close range and allows it to function as a sniper alongside its optical rangefinder. The loader has a KPVT machine gun, excellent for knocking out light armored vehicles. However, the low depression angles of all weaponry make the Object 140 uncomfortable to use on hilly terrain. Its armor is strong enough only to stop APHE shells; any HEAT or APDS round will have no trouble penetrating it. Though the four-man crew allows survival after penetration, bringing only the first-stage ammo rack is strongly advised, as otherwise, rounds will be located throughout the crew compartment. The mobility of Object 140 is sufficient to position it at the tip of the attack or perform flanking maneuvers; however, the 8 km/h reverse speed should be kept in mind.