Bearing adapter side frame interface for a railway car truck

An interface between a railway car side frame and a bearing adapter, the side frame being oriented longitudinally with respect to a railway car, having a pedestal jaw receiving a transversely mounted wheel set;

• the wheelset being received in the pedestal jaw and comprising an axle, a wheel, and a roller bearing;
• the pedestal jaw having opposed end walls, a pedestal roof, and a thrust lug on each of the opposed end walls;
• a bearing adapter received in the pedestal jaw between the roller bearing and the pedestal roof, the bearing adapter having a curved bottom surface facing the roller bearing, an upper surface facing the pedestal roof, and opposed slots mating with the respective thrust lugs on the pedestal jaw end walls;
• the interface comprising:
• an adapter plate positioned between the pedestal roof and the bearing adapter, said adapter plate having a horizontal surface facing the pedestal roof, and first and second legs received in respective slots of the bearing adapter
• the first and second legs each having a surface about perpendicular to the longitudinal axis of the side frame.