The highly successful PS-2 covered hopper was designed by Pullman Standard in the 1940s. This virtually all-welded 2-bay hopper had a 2003 cubic foot capacity and wa well suited for a variety of transportable bulk commodities such as sugar, wheat and oat flour and calcium carbide. However by 1952, the demand for a larger covered hopper was quite evident. Pullman Standard quickly responded with new 3-bay car. This new hopper was just what the railroads and lessees wanted and it soon superseded the 2-bay car in production.