A rail vehicle is disclosed which includes a bottom discharge hopper supported on an elongated, rectangular base frame. A bogie frame is provided beneath the base frame at each end thereof, the bogie frames carrying the vehicle wheels. Each bogie frame comprises two laterally spaced longitudinal members and a transverse member. Bearings are provided between the bogie frame members and the longitudinal and transverse members of the rectangular base frame. These bearings comprise rolling elements in arcuate grooves, the grooves being generated about the vertical pivotal axis of the adjacent bogie frame. Pins are provided which extend downwardly from the base frame and through arcuate slots in the bogie frames. The pins have structures at their lower ends for preventing upward withdrawal thereof through said slots. The slots are generated about the pivotal axis of the adjacent bogie frame.