Covered freight car No. 704 349

During the period of the New Economic Policy (1921–1928) and the beginning of industrialisation, freight traffic in the USSR increased significantly. The need for the industry to adopt and mass produce high-capacity freight cars, which had already shown their advantages over two-axle cars, was clear. While the carrying capacity of two-axle covered wagons can be estimated at 16.5–20 t, four-axle covered wagons can carry 40–50  t.

The Krasnoye Sormovo Plant as well as plants in Bryansk and Tver began experimental production of four-axle covered wagons of various designs in 1925. These experiments led to the start of mass production of covered wagons with a carrying capacity of 50 t based on drawings from the Bryansk Locomotive Works in 1928.