Railcar Truck Roller Bearing Adapter-Pad Systems

Abstract

A railcar truck and adapter pad system for placement between a roller bearing and side frame pedestal roof of a three-piece railcar truck. Many different features of the pad and/or the adapter-pad interface are configured to improve stiffness characteristics to satisfy both curving and high speed performance of the railcar truck.

1 . A roller bearing adapter pad system configured for use with a three-piece truck having a roller bearing adapter and a side frame pedestal roof, the roller bearing adapter pad system comprising:
 an adapter pad comprising:
 a top plate; 
 a bottom plate; and 
 an elastomeric member disposed between the top plate and bottom plate, 
   the elastomeric member comprising a center elastomer layer; and   wherein the center elastomer layer has a shear perimeter of about 20 in. to about 35 in; and   wherein the combined top plate, bottom plate, and elastomeric member provide a longitudinal stiffness of at least 45,000 pounds per inch through a longitudinal displacement of the top plate relative to the bottom plate of up to 0.139 inches from a central position, a lateral stiffness of at least 45,000 pounds per inch through a lateral displacement of the top plate relative to the bottom plate of up to 0.279 inches from the central position, and a rotational stiffness of at least 250,000 pound*inches per radian of rotation through a rotational displacement of the top plate relative to the bottom plate of up to 54.4 milliradians from the central position when a vertical load of 35,000 pounds is applied to a central portion of the adapter pad.