Use of detailed ultrasonics data to monitor rolling contact fatigue and squats in rail

The rails of most mainline tracks are tested periodically by ultrasound cars, principally to find internal rail defects. This paper describes use of the full data logged by such cars, sometimes called “the data tapes”, to assess the condition of the running surface of the rail. Processing techniques have been developed to gather the count numbers (density) of ultrasonic reflections and loss of back wall echo per metre. Once gathered, the data from sequential test runs can be plotted together with configuration and works history data to create a powerful rail surface condition monitoring tool. Rail in good condition has given no ultrasonic returns for hundreds of metres at a stretch, save at welds and bolt holes. In contrast, rail with squat defects, for example, has given hundreds of reflections per metre. The data has varied widely in its output range at unique locations and consistently in repeatability across many locations, thus giving strong promise of holding useful information for rail maintenance strategies. Use of the data is intended to allow a more objective approach to: · Map the locations and estimated severity of the worst rolling contact fatigue. · Estimate degradation rates over time. · Monitor the effectiveness of grinding to remove rolling contact fatigue. · Predict when the accuracy of testing for internal defects may be compromised by rolling contact fatigue or when a rail will become completely untestable. The results have been allowing better identification of the condition and degradation rates of the rail surface when setting scope for rail grinding and re-railing. They are also proving invaluable in the task of assessing very large lengths of track to determine priorities, driving better decisions on risk reduction and cost reduction.

Media Info

  • Pagination: 9p. ; PDF
  • Monograph Title: Maintaining the momentum: CORE 2016: conference on railway excellence, 16-18 May 2016, Melbourne, Victoria, Australia

Subject/Index Terms

Filing Info

  • Accession Number: 01636898
  • Record Type: Publication
  • Source Agency: ARRB
  • Files: ATRI
  • Created Date: May 30 2017 3:31PM