Technical Reports

Evaluation of Wheel-Rail Load and Position Measurement Concepts

  • 01
  • Feb
  • 1982
AUTHOR: M. R. Johnson, R. P. Joyce
OFFICE: RPD
REPORT NUMBER: FRA/ORD-82/20
SUBJECT: Evaluation
KEYWORDS: Railroad Wheels, Wheel-Rail Position, Angle of Attack
ABSTRACT: Concepts for railroad vehicle-borne instrumentation systems which measure wheel-rail loads and wheel position and angle-of-attack relative to the rail were identified and evaluated. A system which provided continuous measurement of lateral and vertical wheel loads, with an accuracy of ± 2 percent of full scale load, and continuous measurement of wheel-rail angle-of-attack with ± 0.5 milliradian (0.029 deg) accuracy was required. The work included a survey of current measurement concepts, the development of an evaluation procedure, the utilization of the procedure, and the development of suitable specifications. Six load measurement systems were considered, 5 based on instrumented wheel plates and one based on an instrumented axle and wheel bearing adapters. Four position measurement systems were evaluated, 2 based on contacting probes and 2 based on noncontacting probes. It was found that an instrumented wheel plate system must be utilized for wheel-rail force measurements if the desired performance standards are to be attained. It was also concluded that none of the wheel-rail position measurement systems would meet the desired performance characteristics. However, the rail contacting systems have the potential, under further development, for approaching the desired characteristics. The need for developing techniques for determining the performance of load measurement systems under dynamic operating conditions was also identified.

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