Tread buildup on railroad wheels.

Details

• Creators:
  Cummings, Scott ; Sammon, Devin
• Corporate Creators:
  Transportation Technology Center, Inc.
• Subject/TRT Terms:
  • Car wheels (Railroads)
  • Railroads
  • Axle loads
  • Chemical analysis
  • Heat transfer
  • Braking
  • Accident causes
• Publication/ Report Number:
  DOT/FRA/ORD-15/06
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States
• Corporate Publisher:
  United States. Federal Railroad Administration. Office of Research and Development
• Abstract:
  Based on the results of wheel slide tests and an inspection of wheels, the root cause of tread buildup (TBU) was identified as ; wheel slide caused by excessive brake force. During the tests, TBU accumulated to the greatest heights under dry conditions, at ; longer slide distances, and under heavier axle loads. Train speeds between 20 and 30 mph appeared to increase TBU height. ; Chemical analysis of TBU samples indicated that the source of the material is likely a combination of wheel and rail steel. This ; finding reinforces the conclusion that wheel slides cause TBU. A microstructural evaluation of several TBU samples found no ; martensite, a microstructure that results when hot steel is rapidly cooled. A relatively slow conductive heat transfer rate from the ; irregular contact between the hot TBU and the cooler wheel likely does not provide sufficiently rapid cooling for martensite ; formation. ; The railroad industry is currently poised to reduce TBU through improved brake system performance as a result of handbrake ; training for train crews, handbrake design improvements, an improved airbrake test, and the increased use of data from wayside ; detectors to identify cars with brake problems. Although TBU removals are decreasing, TBU-related accidents do not show a ; clear trend as a percentage of all wheel-related accidents.
  More +
• Format:
  PDF
• Funding:
  DTFR53-00-C-00012, Task Order 253
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/28987/dot_28987_DS1.pdf
• File Type:
  [PDF - 990.60 KB]
• Collection(s):
  US Transportation Collection ; Federal Railroad Administration
• Main Document Checksum:
  urn:sha256:bfb282501495ff4f91f3d2e2c99fe8c6c4836175b7f3b2be692fa823c5a9ab60