Patent ID: 7603954

Claim:
A rail road freight car truck having a truck bolster mounted cross-wise between first and second sideframes, the sideframes being mounted on wheelsets, wherein: said sideframes are mounted to swing sideways relative to said wheelsets, and each sideframe has an associated pendulum stiffness, k pendulum ; said bolster has first and second ends carried on first and second spring groups mounted in said first and second sideframes, each said spring group having a respective spring group shear stiffness, k spring shear ; said truck has a load rating, and when said truck is fully laded to said rating, said pendulum stiffness k pendulum is softer than k spring shear ; said bolster has a substantial range of lateral travel relative to said sideframes; said range of travel being at least ¾″ to either side of a neutral position; and motion of said bolster in lateral travel relative to said sideframes is limited by co-operating abutting engagement members of said bolster and said sideframe.