Abstract: A bogie having a bolster comprising a center pin support, and elongated support member mounted in center pin support, cam means on the center pin support to co-act with complementary cam means on a wagon to bias the support member to a position transverse to the rail track; two parallel side frames mounted on the respective ends of the support member and lying parallel to the rail track, four wheel supporting arms located one below each end of the side frames, two wheel arm supports one on either side of the support member on each of which is pivotally mounted two of said wheel supporting arms, two downwardly divergent pivotal connections respectively connecting each wheel arm support to the center pin support to bias the wheel supporting arms to a position parallel to the rail track, springs between overlying portions of the side frames and the wheel supporting arms and a wheel rotatably mounted on each wheel supporting arm.