Rail road car and truck therefor
A railroad car truck for a railroad freight car, such as an autorack car, has a bolster mounted cross-wise between two sideframes. The bolster ends are mounted on respective spring groups carried by the sideframes. The bolster can translate laterally relative to the sideframes. The side frames are mounted to swing laterally relative to the wheel sets, and hence relative to the rails. Resistance to lateral deflection is provided by the resistance of the sideframes to the pendulum swinging motion, and by shear in the spring groups. The truck has a doubled damper arrangement of dampers in a four-cornered layout at each end of the bolster, giving a flexing resistance to yaw between the sideframes and the bolster ends. The doubled damper arrangement works against large wear plates mounted on the sideframe columns. The large wear plates are mounted normal to the dampers and square to the sideframes.
1. A railroad freight car truck having a load rating, said truck comprising:
a bolster, sideframes, spring groups and wheelsets;
said bolster being mounted cross-wise to said sideframes;
said bolster having a first end and a second end;
said first and second ends of said bolster being supported on respective ones of said spring groups, said spring groups being carried by said sideframes, said spring groups having vertical spring rates;
said sideframes being swingingly mounted on said wheelsets;
said bolster being moveable through a lateral displacement relative to said sideframes, said lateral displacement having an overall magnitude and including a first component associated with a first lateral stiffness, k pendulum , opposing cross-wise swinging deflection of said sideframes and a second component associated with a second lateral stiffness, k spring shear , opposing sideways shear of said spring groups;
said first lateral stiffness being softer than said second lateral stiffness;
said bolster being movable in non-trivial yaw relative to said sideframes;
dampers mounted to work between said respective ends of said bolster and the sideframes, said dampers having damper wedges, said dampers being mounted yieldingly to oppose yawing of said bolster relative to said sideframes;
said damper wedges each having a first face operable to work against an associated wear surface in a friction relationship, and a second face that seats in a damper wedge pocket, said first and second faces being angled with respect to one another at a primary damper wedge angle, said primary damper wedge angle being at least 35 degrees;
four of said damper wedges are mounted at said first end of said bolster, and four of said damper wedges are mounted at said second end of said bolster; and
said damper wedges also have secondary damper wedge angles oriented cross-wise to said primary damper wedge angles.
2. The railroad freight car truck of claim 1 wherein said damper wedges also have tertiary wedge angles.
3. The railroad freight car truck of claim 1 wherein said first face of each of said damper wedges is a non-metallic face.
4. The railroad freight car truck of claim 1 wherein said truck has a four-cornered group of said damper wedges mounted at each end of said bolster.
5. The railroad freight car truck of claim 4 wherein, when said bolster is angularly deflected relative to a respective one of said sideframes in a yaw-deflected condition, the four-cornered group of dampers associated with that respective sideframe exerts a restorative moment couple linearly proportional to yaw deflection of said bolster.
6. The railroad freight car truck of claim 1 wherein said truck is free of (a) a transom; (b) a frame brace; and (c) unsprung lateral bracing rods mounted cross-wise between said sideframes.
7. The railroad freight car truck of claim 1 wherein:
four of said damper wedges are mounted at said first end of said bolster, and four of said damper wedges are mounted at said second end of said bolster; and
said truck is free of (a) a transom; (b) a frame brace; and (c) unsprung lateral bracing rods, mounted between said sideframes.
8. The railroad freight car truck of claim 1 wherein:
said first face of each of said damper wedges is a non-metallic face; and
said truck is free of (a) a transom; (b) a frame brace; and (c) unsprung lateral bracing rods, mounted between sideframes.
9. A railroad freight car truck having a load rating, said truck comprising:
a bolster, sideframes, spring groups and wheelsets;
said bolster being mounted cross-wise to said sideframes;
said bolster having a first end and a second end;
said first and second ends of said bolster being supported on respective ones of said spring groups, said spring groups being carried by said sideframes, said spring groups having vertical spring rates;
said sideframes being swingingly mounted on said wheelsets;
said bolster being movable in non-trivial yaw relative to said sideframes;
said bolster being moveable through a lateral displacement relative to said sideframes, said lateral displacement having an overall magnitude and including a first component associated with a first lateral stiffness, k pendulum , opposing cross-wise swinging deflection of said sideframes and a second component associated with a second lateral stiffness, k spring shear , opposing sideways shear of said spring groups;
said first lateral stiffness being softer than said second lateral stiffness;
said truck has damper wedges mounted at each end of said bolster, and said damper wedges have primary wedge angles of at least 35 degrees; and
said dampers also have secondary damper wedge angles oriented cross-wise to said primary damper wedge angles.
10. The railroad freight car truck of claim 9 wherein said truck has a four-cornered group of damper wedges mounted at each end of said bolster.
11. The railroad freight car truck of claim 10 wherein said damper wedges each have a first face that works against an associated wear surface in a friction relationship, and said first face of each of said damper wedges is a non-metallic face.
12. The railroad freight car truck of claim 9 wherein:
said truck has yaw resisting members mounted yieldingly to oppose yawing of said bolster relative to said sideframes; and
said yaw resisting members include a group of said yaw resisting members mounted at each end of said bolster, and said groups each include at least a first yaw resisting member and a second yaw resisting member, said first yaw resisting member being mounted laterally inboard of said second yaw resisting member.
13. The railroad car truck of claim 9 wherein said truck has yaw resisting members mounted yieldingly to oppose yawing of said bolster relative to said sideframes; said yaw resisting members include a group of four such yaw resisting members mounted at each end of said bolster in a four-cornered arrangement; said yaw resisting members are damper wedges; said damper wedges are driven by a spring of one of said spring groups; and each said damper wedge is mounted to work between said bolster and one of said sideframes.
14. The railroad freight car truck of claim 13 wherein, when said bolster is angularly deflected relative to a respective one of said sideframes in a yaw-deflected condition, the four-cornered arrangement of yaw resisting members associated with that respective sideframe exerts a restorative moment couple linearly proportional to yaw deflection of said bolster.
15. A railroad freight car truck having:
a bolster extending cross-wise between a pair of sideframes, said sideframes being swingingly mounted on wheelsets, said sideframes having a pendulum stiffness resistant to lateral swinging deflection thereof;
said sideframes being yawingly mounted relative to said bolster;
said bolster having a first end and a second end;
said first and second ends of said bolster being supported on respective ones of said spring groups, said spring groups being carried by said sideframes, said spring groups each having a lateral shear stiffness;
there being a four-cornered group of dampers mounted at each end of said bolster, said groups of dampers being biased resiliently to restore said sideframes from a yaw-deflected condition to a squared condition relative to said bolster;
said pendulum stiffnesses and said lateral shear stiffnesses combining to resist lateral deflection of said bolster relative to said wheelsets; and
said main spring group lateral shear stiffnesses being stiffer than said pendulum stiffnesses;
said dampers include damper wedges, said damper wedges having a primary damper wedge angle and a secondary damper wedge angle oriented cross-wise to said primary damper wedge angle.
16. The railroad freight car truck of claim 15 wherein, when said bolster is angularly deflected relative to a respective one of said sideframes in said yaw-deflected condition, the damper group associated with that respective sideframe exerts a restorative moment couple linearly proportional to yaw deflection of said bolster.
17. The railroad freight car truck of claim 15 wherein said damper wedges each has a first face for working against an associated wear surface in a friction relationship, and said first face of each of said damper wedges is a non-metallic face.
18. The railroad freight car truck of claim 15 wherein said truck is free of (a) a transom; (b) a frame brace; and (c) unsprung lateral bracing rods mounted cross-wise between said sideframes.