Center plate structure for railway vehicle

In a railway vehicle, having a body provided with a body bolster and a body center plate, said body center plate having a supported planar bottom surface adjoined by a cylindrical outside surface, a truck provided with a truck bolster and a bolster bowl, said bolster bowl having a planar supporting surface adjoined by an upstanding peripheral flange which has a cylindrical inside surface which is adapted to receive said outside surface therewithin, a wear resistant tubular liner disposed in sandwiched relation between said cylindrical surfaces with said body center plate disposed within said bolster bowl, said tubular liner being comprised of an ultra high molecular weight polymeric material and having a top surface, the improvement comprising a continuous metal ring fixed to said flange against a top portion of said inside surface, said metal ring having a continuous substantially frustoconical annular bottom surface which has a central axis which coincides with a central vertical axis through said bolster bowl and which is adapted to engage said top surface of said tubular liner, said frustoconical surface being inclined so that it faces away from said vertical axis and defines a cam surface which serves to urge the top portion of said liner radially toward said flange, said ring serving to prevent vertical cold flow of the polymeric material comprising said tubular liner from between said cylindrical surfaces.