MxV Rail has investigated the performance and service life of reconditioned bearings. The reconditioning of bearings, a common practice in the North American railroad industry, occurs every time a bearing is removed from an axle. At least 85 percent of bearings in revenue service have been through the reconditioning process,1 which involves the disassembly, inspection, repair (if needed), and re-assembly of the bearing.   MxV Rail’s evaluation, part of the Association of American Railroads’ (AAR) Strategic Research Initiatives (SRI) program, was divided into two testing phases. Phase 1 focused on evaluating changes to both the operating temperature and the vibration of the bearing just before and after the repair of spalls in the bearing raceways. Phase 2, as discussed in this Technology Digest, explored the expected service life of repaired spalls.  During testing, MxV Rail studied the bearings that had raceway spalling— the most common type of condemnable failure mode according…