As part of the Association of American Railroads (AAR) Strategic Research Initiative (SRI) program, MxV Rail reviewed service life trends for wheels in bulk commodity rail service. Information from these trends guides focused research to extend the useful life of wheels. Introduction For the purposes of this analysis, the term “bulk commodity” refers to four-axle cars with a design gross rail load (GRL) of 143 tons and is specific to hopper, gondola, and tank car types. Wheels operating in bulk commodity rail transporation have highly variable service lives and are removed from service for a multitude of reasons including environmental conditions, car design, and tread braking duty cycles based on routing, which are an inherent part of the movement of goods by rail. Other reasons for wheel removal provide opportunities for research and adaptation to extend wheel life. These opportunities include wheel/rail profile design, friction management, improved suspension design, and…