Theoretical and experimental determination of heat flow into a wheel due to bearing overheating

Heat-transfer calculations of the rate of temperature rise in the hub and hub-plate fillet of a railroad wheel due to journal over-heating during bearing failure are presented. Three cases are analyzed. The first case is that of a journal with a steady-state high temperature. The second case is an attempt to simulate a burnoff. The third case uses a time-temperature history gathered during seizure of a freight car bearing. Results of the calculations indicate minimal temperature increases in the wheel due to journal heat input. An experimental program was carried out to validate the results of the theoretical analysis. The journal of a 70 ton wheelset was heated electrically and the rate of temperature rise in the hub and hub-plate fillet of the wheel was monitored by thermocouples. Results of the experimental program verified the calculated results for case one. The results of this study raise questions as to the efficacy of systems which use wheel-temperature readings to identify bearings progressing toward failure