In February of 1933, the first ten serial produced T-28 tanks were delivered. The standard production model (m/1934) used the same main and sub-turrets as the T-35 heavy tank. About 600 units were manufactured from 1934 to 1940. The were used in 1939-40 in the Winter War in Finland where they suffered heavily, as they were found to be clumsy, slow and bad armoured.
A project started for up-armoring and many 1938 models were provided with thicker hull. At the German attack in 1941 there were still 232 in army-service for limited use. Several prototypes were based on the T-28 but none was accepted for production.