Wayside roller bearing defect detection

Railway Age, March, 1997

AAR completed an extensive laboratory test of various bearing defects during 1996 to provide acoustic emission characteristics to suppliers, universities, and national laboratories.

An AAR strategic research goal is to promote development of an improved bearing detection system for wayside use. The Federal Railroad Administration is working jointly with AAK to achieve this goal.

While the lab test provided clean data on each of the defect types (spalls, water etch, roller defects, spun cone), field test data collected from a simulated revenue service test conducted at TTC provided similar data for a moving train with all its associated background noise.

The lab test provided data from a single microphone listening to a single bearing. The field test used an array of 12 microphones spread out over 40 feet (four-wheel revolutions) listening to an eight-car train with 32 test bearings (on one side of the train). Of the 32 test bearings, there were 18 defective bearings and 14 "good remanufactured" (no known component defects) bearings.

The data from the field test also was sent to about 30 program participants as well as analyzed by TTC. In addition to the data collected in this program, four other participants collected their own wayside data for system development.

AAR researchers will be developing a prototype analytical system for identifying beating defects based on data from this test program. Based on a review of the lab data, each of the defect types could be identified in the acoustic emission data. It is expected that the AAR system and other working prototypes of improved wayside beating detector systems will be available by the end of 1997. Contact Gerald Anderson at (719) 584-0587 with questions or comments.