Patent attributes
A rail road freight car truck has a truck bolster mounted transversely between a pair of side frames. The mounting interface between the wheelset axle ends and the sideframe pedestals allows self-restorative longitudinal rocking self-steering motion proportionately resisted as a function of displacement and of the vertical force carried at the interface. The center of rotation of the rocking motion is lower than the center of rotation of the axle. The interface may also permit lateral rocking swing motion of the sideframes. Auxiliary centering elements may be mounted in the pedestal seats. The auxiliary centering elements may be elastomeric. The truck may also have low stick-slip friction dampers, and may be provided with brake linings, or similar features. The friction dampers may be mounted in a four-cornered arrangement at each end of the truck bolster.