Dampened railway car truck

Claim 1

In a railway car truck comprising a pair of side frames rockably journaled on associated wheel and axle assemblies for lateral swinging movement under the action of laterally directed forces applied to the truck, each frame comprising a tension member having a base portion and a pair of vertical columns extending upwardly from the base portion and spaced in the lengthwise direction of the frame to define a bolster opening, a spring plank extending between said frames with each end of said plank being received in said opening of the adjacent frame, rocker means between each end of said plank and said base portion of each frame for supporting said plank for rocking movement in a direction laterally of said frames, means interconnecting the ends of said plank and said frames to interlock said frames to the plank, a bolster extending between said frames and supported at its ends within the bolster opening of the adjacent frame, spring means on said plank within each opening for supporting said bolster end first stop means on said bolster and plank adapted to engage upon a predetermined amount of lateral swinging movement of said frames and transverse deflection of said spring means to limit the lateral movement of said bolster relative to said frames, said stop means engaging at a point below the plane containing the axes of the axles and a friction shoe interposed between and resiliently urged into engagement with a side of said bolster and the opposing one of said columns for frictionally resisting movement of said bolster; the improvement comprising: second stop means associated with each end of the spring plank and engageable with stop means on said base portion of the side frames for limiting said predetermined amount of swinging movement of the side frames in either direction from the central longitudinal vertical plane of the side frame prior to the engagement of said first stop means, said first and second stop means establishing a non-linear, lateral force-travel curve comprising a first stage and a second stage defining the resistance to lateral movement of said bolster relative to said side frame.