A Collaborative On-Track Field Test Conducted to Verify the Laboratory Findings on Bearing Temperature Trending

Abstract

Over the last three years, numerous laboratory tests have been conducted with the goal of identifying the root cause of the temperature trending phenomenon observed in tapered roller bearings during their field service. The experimental efforts were successful in duplicating the temperature trending phenomenon in the lab, and concluded that vibration induced roller misalignment was responsible for this troubling phenomenon; yet field verification of these findings was still missing. To this end, a collaborative on-track field test was carefully planned and executed by The Amsted Rail Company, The Union Pacific Railroad (UP), Rail Sciences Inc. (RSI), and The University of Texas-Pan American (UTPA). A locomotive, a business car, and two coal cars — one fully loaded and one empty — were made available by the UP for the purposes of this test. Four bearings that exhibited temperature trending during the laboratory testing, and two other bearings that were set-out for temperature trending by the UP, were mounted next to six high impact wheels of at least 70 kips. The impact wheels were used as external vibration sources. Three of these wheels were placed under the fully loaded coal car, and the other three under the empty car. The remaining components used in the test were all defect free bearings and wheels. All sixteen bearings were instrumented with thermocouples and accelerometers, with four additional accelerometers monitoring the track joints and defects and the car pitch and bounce. This paper provides a summary of the initial analysis of the acquired data which indicates that the field test was successful in verifying the laboratory findings.