CONSEQUENCES OF VARIATIONS IN ULTRASONIC WHEEL PROBES FOR AUTOMATED RAIL FLAW DETECTION SYSTEMS

At the Transportation Systems Center, an ongoing project is the development of a computer-based Automated Rail Flaw Detection System. The core of this system is ultrasonics. An ultrasonic signal is both transmitted and received by one or more transducers that are mounted in fluid-filled wheels that scan the rails. The wheels and associated electronics are mounted on a Track Inspection Vehicle. At present, one of the technological problems that is holding back the development of the Automatic Flaw Detection System is the lack of standardization in the production of the wheel probes. Minor variations in the wheel probe significantly affect the rail area to be measured. Similarly, small differences in signal strength, water path length and internal fluid temperature also significantly affect results.