In 1935, even before the influence of the Spanish Civil War, the Red Army was looking to modernize its tank fleet. The objective of a fast moving convertible drive tank with a diesel engine was only achieved with the BT-7M tank in 1938.
"Based on the direction of work on improving existing fighting vehicles to create fast moving convertible drive operational tanks with diesel motors by the 4th years of the 2nd five year plan, the new T-26A convertible drive tank needs to be introduced to replace the T-26 and BT, instead of the PT-1 and T-28 tanks, a new convertible drive T-28-B tank with a powerful diesel motor. The rest of the tanks can be retained without major changes.
T-28-B tank:
- Mass: 20 tons
- Armour: 30 mm
- Armament: 1 76 mm gun and 3 super rapid fire machine guns
- Motor: special 500 hp diesel
- Speed: 70 kph on wheels, 50 kph on tracks
- Range: 200 km on tracks, 300 km on wheels
- Crew: 6
- Maximum trench crossing width: 3.3 m
- Maximum vertical obstacle crossing height: 0.85 m
- Maximum fording depth: 1 m"