Rail and Joint Bar (Fish Plate) NDE Advances in North America

Improvement and development of rail track nondestructive inspection (NDI) technologies to reduce in-service failures of rail and joint bars (fish plates) in a continuous effort to make rail transport safer is a primary focus for the railroad industry. Researchers at The Transportation Technology Center, Inc., working under the direction of the Association of American Railroads and its Strategic Research Initiative Program, have worked with companies worldwide to develop novel NDI approaches for dynamic inspection of rail and joint bars. In the area of rail inspection an ultrasonic rail (U-Rail) system for noncontact rail flaw inspection has been developed. This system combines high energy lasers with air-coupled transducers to dynamically inspect full rail sections. Pulsed lasers generate ultrasonic signals and air-coupled transducers monitor the waves that propagate through the rail. An ultrasonic based joint bar inspection system has also been developed. This system inspects joint bars in track by using a conventional ultrasonic approach. Scanning is performed from the outside surface of the bar in order to detect flaws located at the bars inside surface. Evaluations of the NDI systems have been performed at the United States Department of Transportation, Federal Railroad Administration’s, Transportation Technology Center, located near Pueblo, Colorado, USA.