Abstract: In accordance with the invention a center filler assembly is inserted into a railway car center sill and is permanently attached to the center sill. The center filler includes longitudinally spaced vertical plates which extend between the walls of the center sill. Spacer extensions integral with the vertical plates extend beyond the walls of the center sill and abut the bottom surface of the center sill flanges. A mounting plate extends longitudinally of the car between the center filler vertical plates. A wear member in adopted to be located in the truck bowl. Interengaging means are provided to removably lock the wear member is engagement with the mounting plate. This interengaging means preferably comprises slots in the wear member which engage the spacer extensions integral with the vertical plates.