Patent ID: 7631603
Filing Date: 2009-12-15
Classification: B61F

Abstract:
1. A three-piece railroad freight car truck having a bolster sprung between a pair of first and second sideframes, said bolster being sprung on first and second main spring groups carried by said first and second sideframes respectively, each of said main spring groups including coil springs, said truck including friction dampers mounted to work between the bolster and the sideframes, said bolster being mounted to permit limited lateral travel thereof relative to said sideframes, said truck having co-operating members constraining said bolster to a first bounded range of lateral travel relative to said sideframes when loaded under a first magnitude of vertical load, and to a second, different, bounded range of lateral travel relative to said sideframes under a second, different magnitude of vertical load, said co-operating members defining the bounds of said first and second bounded ranges of lateral travel.