Self-steering radial bogie

1. A self-steering system for a radial bogie of a railroad vehicle, the radial bogie having a frame with longitudinally extending side members laterally spaced by transoms and leading and trailing ends, the radial bogie further including a leading and trailing wheelset supported on said frame, said self-steering system comprising:

a damper connected to the frame of the bogie;

a link having a first and second end, the first end of the link connected to one of the wheelsets, the second end of the link connected to:

the frame of the bogie at a first position of the second end, and

the damper at a second position of the second end;

the first end of the link including a first bushing; and

the second end of the link including a second bushing, the first bushing having a longitudinal stiffness different than the longitudinal stiffness of the second bushing.

2. The self-steering system of claim 1 further comprising another link situated between the longitudinally extending side members of the frame, said other link connecting one of the wheelsets to a transverse end of the frame of the bogie.

3. The self-steering system of claim 1 wherein the first end of the link includes a journal housing for engaging the wheelset.

4. The self-steering system of claim 1 wherein the first bushing has a longitudinal stiffness of at least 35 kN/mm.

5. The self-steering system of claim 1 wherein the first bushing has a longitudinal stiffness of about 60 kN/mm to about 100 kN/mm.

6. The self-steering system of claim 1 wherein the first bushing has a vertical stiffness of at least 35 kN/mm.

7. The self-steering system of claim 1 , wherein the second bushing includes a resilient material.

8. The self-steering system of claim 1 , wherein the second bushing includes either a polymer or rubber.

9. The self-steering system of claim 1 , wherein the second bushing has a progressive longitudinal stiffness over a range of displacement values.

10. The self-steering system of claim 9 , wherein the second bushing has a linearly increasing longitudinal stiffness ranging from about 0 kN/mm to about 7 kN/mm over displacement range of about −4 mm to about 4 mm.

11. The self-steering system of claim 10 , wherein the second bushing has a linearly increasing longitudinal stiffness ranging from about 2 kN/mm to about 4 kN/mm over displacement range of about 2 mm to about 4 mm.

12. The self-steering system of claim 10 , wherein the second bushing has a linearly increasing longitudinal stiffness ranging from about 2 kN/mm to about 4 kN/mm over displacement range of about −2 mm to about −4 mm.

13. The self-steering system of claim 9 , wherein the second bushing has an exponentially increasing longitudinal stiffness ranging from about 4 kN/mm to about 150 kN/mm over displacement range starting at about −4 mm.

14. The self-steering system of claim 9 , wherein the second bushing has an exponentially increasing longitudinal stiffness ranging from about 4 kN/mm to about 150 kN/mm over displacement range starting at about 4 mm.

15. The self-steering system of claim 1 , wherein the second bushing has a vertical stiffness of about 20 kN/mm.

16. The self-steering system of claim 1 , wherein the link is a traction link.

17. A radial bogie for a railroad vehicle, comprising:

a frame with longitudinally extending side members laterally spaced by transoms and leading and trailing ends;

a leading and trailing wheelset supported on said frame, and a plurality of links situated between each wheelset and the frame, each link having a first and second end, the first end of each link connected to one of the wheelsets and the second end of each link connected to the frame of the bogie;

the first end of each link including a first bushing; and

the second end of each link including a second bushing, the first bushing having a longitudinal stiffness greater than the longitudinal stiffness of the second bushing; and

a damper connected to the frame and to the second end of one of the links, a longitudinal axis of the damper extending through the second bushing of one of the links.

18. The radial bogie of claim 17 , wherein each wheelset is connected to the frame by at least two links.

19. The radial bogie of claim 17 , wherein the damper is one of a plurality of dampers, each damper being situated between the second end of one of the links and the frame of the bogie.

20. The radial bogie of claim 17 wherein the links are situated near the longitudinally extending side members of the frame.

21. The radial bogie of claim 17 further comprising another link situated between the longitudinally extending side members, said other link connecting one of the wheelsets to a transverse end of the frame of the bogie.

22. The radial bogie of claim 17 , wherein the second bushing includes a resilient material.

23. The radial bogie of claim 17 , wherein the second end of each link is connected to the frame at a first position of the second end and to the damper at a second position of the second end.

24. The radial bogie of claim 23 , wherein the damper connects the second end of one of the links to the frame without a steering beam.

25. A radial bogie for a railroad vehicle, comprising:

a frame with longitudinally extending side members laterally spaced by transoms and leading and trailing ends;

a leading and trailing wheelset supported on said frame, and a plurality of links situated between each wheelset and the frame, each link having a first and second end, the first end of each link connected to one of the wheelsets and the second end of each link connected to a fixed portion of the frame of the bogie so that there is a smaller degree of movement between the wheelset and the first end of each link compared to the amount of movement between the frame of the bogie and the second end of each link; and

a damper connecting the second end of one of the links to the frame without a steering beam.