Abstract: Constant contact side bearing support of a rail car body on a multi-axle rail car truck is provided for the purpose of restraining truck hunting and controlling car rocking. A bearing receiver or cage mounted on the truck bolster in laterally offset relationship to the truck center plate bowl supports wedge shaped bearing blocks on inclined surfaces within the cage. Biasing means, e.g., a long travel coil spring, biases the bearing blocks against the inclined surfaces of the cage, thereby maintaining a substantially constant normal bearing force on the car body throughout the wear life of the bearings. In an alterative embodiment, the cage is mounted on the car body with the bearing surfaces of the bearing blocks engaging corresponding bearing surfaces on the bolster. Arrangements providing for ease of inspection and replacement of the bearing blocks are disclosed.