Acoustic wayside identification of freight car roller bearing defects

Over the past few years, the Association of American Railroads (AAR) has developed several new techniques for detecting defective roller bearings as part of their new generation wayside acoustic detector program. This paper reviews some of the wayside acoustic data collected from a simulated revenue service test train containing 18 known defective bearings. All performance testing was done November 1996 by Transportation Technology Center Inc. (TTCI), a subsidiary of the AAR, at the Transportation Technology Center (TTC), Pueblo, Colorado. This document presents the character of the collected acoustic data from the defective bearings as they operated under full service conditions. Time-based and spectral tracings are displayed, demonstrating that defective bearing conditions can be identified on-the-fly from wayside microphones. The examined data is the foundation of the development, manufacture and installation of a new online acoustic wayside detection system.