Wheelset to side frame interconnection for a railway car truck

A railway car truck, comprising:

• first and second side frames each having a leading pedestal jaw and a trailing pedestal jaw, said first and second side frames being in opposed relationship and parallel, and the leading and trailing pedestal jaws being aligned to receive transversely mounted leading and trailing wheel sets respectively;
• each wheelset being received in the pedestal jaws and comprising an axle, wheels, and roller bearings;
• each pedestal jaw comprising leading and trailing side walls and a pedestal roof;
• a bearing adapter received in each pedestal jaw between the roller bearing and the pedestal roof, the bearing adapter having a curved bottom surface facing the roller bearing and flat upper surface facing the pedestal roof;
• a thrust lug on each of the leading and trailing side walls of the pedestal jaw mating with respective slots on the leading and trailing sides of the bearing adapter;
• compressed elastomeric members positioned between each respective thrust lug and slot providing opposed forces in the longitudinal direction on the bearing adapter when the truck is stationary;
• and
• an interface between the pedestal roof and the bearing adapter having a static coefficient of friction less than 0.08;
• wherein the compressed elastomeric members and the interface between the pedestal roof and the bearing adapter provide a lateral spring constant less than 5000 lb/in and a longitudinal spring constant between 20,000 lb/in and 40,000 lb/in, and a restoring force in response to a load applied to the truck.