Rail road car truck and bearing adapter fitting therefor

A bearing adapter for installation between a bearing of a railroad car truck wheelset and a pedestal mounting of a railroad car truck sideframe, the wheelset bearing having an axis of rotation defining an axial direction, and first and second axially spaced apart bearing races contained within a bearing casing, the bearing races extending about the axis in a circumferential direction, the pedestal mounting having a roof that, in operation, lies over the bearing, wherein said bearing adapter comprises:

• a body having a first scat for engagement with the casing of the wheel bearing, and a second seat for orientation facing toward the pedestal mounting roof;
• said first seat including first and second side portions having surfaces for mating with the bearing casing at circumferentially spaced apart locations abreast of one of the bearing races;
• said first seat including a central portion located circumferentially between said side portions, at least part of said central portion including a relief;
• and,
• said bearing adapter being mountable on the bearing in a position in which said relief of said part of said central portion is located abreast of and above one of the bearing races and said first and second portions are located circumferentially to either side of top dead center of the bearing respectively, and, when so mounted, said first and second portions defining dominant load transfer interfaces from said bearing adapter into said bearing for vertical loads from the sideframe passed into said bearing adapter at said second seat.