Patent ID: 7263931

Claim:
A rail road car truck having: a first sideframe and a second sideframe spaced apart therefrom; a truck bolster mounted in a cross-wise direction between the first and second sideframes, the truck bolster having first and second ends mounted on respective first and second spring groups mounted in the sideframes; said sideframes having sideframe pedestals, each pedestal having a rocker member fixedly mounted in an uppermost portion thereof by which to mount the sideframes on wheelsets; said sideframes being mounted to rock angularly sideways; said truck having a response to lateral track perturbations that is dominated by resistance of said sideframes to sideways rocking motion; said bolster having a range of sideways travel relative to said sideframes, the range of sideways travel including a first component corresponding to lateral swinging deflection of the sideframes and a second component corresponding to lateral shear deflection of the spring groups, the first component having a magnitude greater than the second component, and the range of sideways travel having a magnitude greater than the magnitude of the first component; a first group of friction dampers mounted to work between said first end of said bolster and said first sideframe, and a second group of friction dampers mounted to work between said second end of said bolster and said second sideframe; and said first group of friction dampers including a first friction damper driven by a first spring, a second friction damper driven by a second spring, said second spring being offset sideways from said first spring, and said first damper being laterally outboard of said second friction damper.