A swing motion rail road freight car truck is provided that has a truck bolster and a pair of side frames, the truck bolster being mounted transversely relative to the side frames. The side frames have spring seats for the groups of springs. The springs seats may be rigidly mounted in the side frames. Friction dampers are provided in inboard and outboard pairs. The biasing force on the dampers urges then to that act between the bolster ands and sideframes to resist parallelogram deflection of the truck. The bearing adapters and sideframe pedestal seats interact on a rolling linear contact interface that has a relatively small radius of curvature.