Rail car side bearing

1. A side bearing for supporting a body of a rail car, the side bearing comprising:

a base for being mounted to a truck of the rail car;

a support configured to contact the body of the rail car and move along a vertical axis relative to the base with movement of the body;

at least one resilient foam member including a matrix of elastomeric material and air pockets therein, the at least one resilient foam member configured to deform with movement of the support;

at least one friction damping member configured to be urged in a direction transverse to the vertical axis against the base by the support and resist movement of the support relative to the base;

wherein the at least one resilient foam member imparts a reactionary force in response to deformation of the at least one resilient foam member from an initial configuration to a compressed configuration caused by movement of the support toward the base with rolling of the rail car body toward the side bearing, the deformation of the at least one resilient foam member from the initial configuration to the compressed configuration decreasing the size of the air pockets of the resilient foam member;

wherein the at least one resilient foam member imparts a restoring force in response to the at least one resilient foam member returning from the compressed configuration to a less compressed configuration caused by movement of the support away from the base with rolling of the rail car body away from the side bearing, the returning of the at least one resilient foam member from the compressed configuration to the less compressed configuration increasing the size of the air pockets; and

wherein the matrix of elastomeric material of the at least one resilient foam member provides internal hysteresis damping such that the restoring force is less than the reactionary force to limit the energy the at least one resilient foam member imparts to the rolling rail car body.

2. The side bearing of claim 1 wherein the support and the at least one friction damping member include a pair of engaged surfaces extending obliquely to the vertical axis.

3. The side bearing of claim 1 wherein the at least one friction damping member includes a pair of friction damping members that are configured to be urged in opposite directions against the base by the support.

4. The side bearing of claim 1 wherein the base includes at least one flat wall adjacent the resilient foam member and the at least one friction damping member is configured to slide along the at least one flat wall.

5. The side bearing of claim 1 wherein the at least one resilient foam member comprises microcellular urethane.

6. The side bearing of claim 1 wherein the at least one resilient foam member has a volume and the air pockets constitute approximately 30 percent to approximately 50 percent of the volume of the at least one resilient foam member.

7. The side bearing of claim 1 wherein the at least one resilient foam member has an open cell configuration that permits air to travel out of the air pockets as the resilient foam member deforms from the initial configuration to the compressed configuration.

8. A side bearing for supporting a body of a rail car, the side bearing comprising:

a base for being mounted to a truck of the rail car;

a support configured to contact the body of the rail car and move along a vertical axis relative to the base with movement of the body;

at least one resilient foam member configured to deform with movement of the support;

at least one friction damping member configured to be urged in a direction transverse to the vertical axis against the base by the support and resist movement of the support relative to the base; and

a damping body intermediate the support and the at least one resilient foam member, the damping body configured to urge the at least one friction damping member in the direction transverse to the vertical axis against the base.

9. The side bearing of claim 8 wherein the support is movable along the vertical axis between upper and lower positions and the at least one friction damping member and the damping body include a first pair of engaged surfaces extending obliquely to the vertical axis.

10. The side bearing of claim 9 wherein the support and the at least one friction damping member include a second pair of engaged surfaces extending obliquely to the vertical axis.

11. A side bearing for supporting a body of a rail car, the side bearing comprising:

a base for being mounted to a truck of the rail car;

a support configured to contact the body of the rail car and move along a vertical axis relative to the base with movement of the body;

at least one resilient foam member configured to deform with movement of the support;

at least one friction damping member configured to be urged in a direction transverse to the vertical axis against the base by the support and resist movement of the support relative to the base; and

wherein the at least one resilient foam member includes a pair of resilient foam members.

12. The side bearing of claim 11 wherein the base includes a center wall intermediate the pair of resilient foam members.

13. A side bearing for supporting a body of a rail car, the side bearing comprising:

a base for being mounted to a truck of the rail car;

a support configured to contact the body of the rail car and move along a vertical axis relative to the base with movement of the body;

at least one resilient foam member configured to deform with movement of the support;

at least one friction damping member configured to be urged in a direction transverse to the vertical axis against the base by the support and resist movement of the support relative to the base; and

wherein the at least one resilient foam member has an unloaded height and the at least one resilient foam member is resiliently compressible to at least seventy percent of the unloaded height.

14. A rail car comprising:

a rail car body;

a pair of trucks supporting the rail car body;

a pair of side bearings of each truck on opposite sides of the rail car body, each side bearing including:

a base;

a support configured to contact the rail car body and move along a vertical axis relative to the base with movement of the rail car body relative to the truck;

at least one resilient foam member arranged to deform with movement of the support;

at least one friction damping member configured to be urged in a direction transverse to the vertical axis against the base by the support and resist movement of the support relative to the base; and

wherein each side bearing includes a damping body intermediate the support and the at least one resilient foam member, the damping body configured to urge the at least one friction damping member in the direction transverse to the vertical axis against the base.

15. The rail car of claim 14 wherein the support and the at least one friction damping member include a pair of engaged surfaces extending obliquely to the vertical axis of the support.

16. The rail car of claim 14 wherein the at least one friction damping member and the damping body include a first pair of engaged surfaces extending obliquely to the vertical axis.

17. The rail car of claim 14 wherein the at least one friction damping member includes a pair of friction damping members that slide along the base and resist movement of the support relative to the base.

18. The rail car of claim 14 wherein the base includes at least one flat wall and the at least one friction damping member is configured to slide along the at least one flat wall.

19. A rail car of claim 14 comprising:

a rail car body;

a pair of trucks supporting the rail car body;

a pair of side bearings of each truck on opposite sides of the rail car body, each side bearing including:

a base;

a support configured to contact the rail car body and move along a vertical axis relative to the base with movement of the rail car body relative to the truck;

at least one resilient foam member arranged to deform with movement of the support;

at least one friction damping member configured to be urged in a direction transverse to the vertical axis against the base by the support and resist movement of the support relative to the base; and

wherein the side bearings each include a hard stop that limits rolling movement of the rail car body to a predetermined range of motion and the resilient foam members of the side bearings are configured to keep the supports of the side bearings in contact with the rail car body throughout the range of motion of the rail car body.

20. The rail car of claim 19 wherein the hard stop includes surfaces of the support and the base extending transverse to the vertical axis.

21. The rail car of claim 19 wherein the base includes walls with the at least one foam member between the walls; and

wherein the hard stop includes portions of the walls and portions of the support.

22. A side bearing for supporting a body of a rail car, the side bearing comprising:

a base for being mounted to a truck of the rail car;

a compartment of the base;

at least one resilient member in the compartment;

a pair of wall portions of the compartment;

a cap assembly supported on the at least one resilient member and configured to move relative to the base with movement of the body of the rail car;

a pair of friction damping members of the cap assembly facing the wall portions of the compartment of the base;

a cap of the cap assembly having an upper surface for contacting the body of the rail car and at least one lower surface configured to contact the friction damping members and urge the friction damping members in opposite directions against the wall portions to dampen movement of the cap assembly; and

wherein the at least one lower surface of the cap includes a pair of inclined surfaces and the friction damping members each include an inclined surface engaged with one of the inclined surfaces of the cap.

23. The side bearing of claim 22 wherein the cap assembly includes a damping body and the friction damping members are sandwiched between the cap and the damping body.

24. A side bearing for supporting a body of a rail car, the side bearing comprising:

a base for being mounted to a truck of the rail car;

a compartment of the base;

at least one resilient member in the compartment;

a pair of wall portions of the compartment;

a cap assembly supported on the at least one resilient member and configured to move relative to the base with movement of the body of the rail car;

a pair of friction damping members of the cap assembly facing the wall portions of the compartment of the base;

a cap of the cap assembly having an upper surface for contacting the body of the rail car and at least one lower surface configured to contact the friction damping members and urge the friction damping members in opposite directions against the wall portions to dampen movement of the cap assembly; and

wherein the at least one lower surface of the cap is configured to contact the friction damping members and urge the friction damping members toward each other in opposite directions against the wall portions.

25. The side bearing of claim 24 wherein the base comprises a center wall that includes the wall portions thereon.

26. The side bearing of claim 24 wherein the wall portions, the friction damping members, or both the wall portions and friction damping members include a coating.

27. The side bearing of claim 24 wherein the at least one resilient member includes a pair of resilient members; and

wherein the base includes a wall intermediate the resilient members.

28. The side bearing of claim 27 wherein the cap body includes a damping body, the friction damping members sandwiched between the cap and the damping body; and

wherein the damping body includes a central opening and the wall of the base extends in the opening of the damping body.

29. The side bearing of claim 24 wherein the cap assembly includes a damping body, the friction damping members intermediate the cap and the damping body; and

wherein the friction damping members have lower surfaces and the damping body includes upper surfaces configured to contact the lower surfaces of the friction damping members and urge the friction damping members toward each other in the opposite directions against the wall portions.