THE CAUSE OF THERMAL FATIGUE CRACKING IN METROLINER WHEELS

One new wheel and two used wheels (one with a thermal crack in the tread) were examined for mechanical properties, macrostructure, microstructure, and residual stresses. Similar examinations were conducted on three new wheels which were first subjected to various braking cycles designed to define the conditions that produce cracking. The braking tests were conducted on the laboratory dynamometer. The results of this study indicated that the wheel that had developed a thermal crack in service had been intermittently and severely heated around the tread surface and that such heating had altered the microstructure, produced residual tensile stresses and permitted the crack to initiate. The results further showed that neither altered microstructures nor cracking could be produced by many emergency brakings or speed-reduction brakings with normal brake shoes and forces.

• Record URL:
  • https://railroads.dot.gov/elibrary/cause-thermal-fatigue-cracking-metroliner-wheels
• 
• Corporate Authors:

  United States Steel Corporation

  125 Jamison Lane
  Monroeville, PA  United States  15146

  Federal Railroad Administration

  Office of Research and Development, 1200 New Jersey Avenue, SE
  Washington, DC  United States  20590

  Transportation Systems Center

  55 Broadway, Kendall Square
  Cambridge, MA  United States  02142
• Authors:
  • CARPENTER, G F
• Publication Date: 1977-3

Media Info

• Media Type: Digital/other
• Pagination: 88 p.

Subject/Index Terms

• TRT Terms: Braking; Braking performance; Cracking; Defects; Fatigue (Mechanics); Fracture mechanics; Metallography; Metallurgy; Microstructure; Railroad cars; Rapid transit; Residual stress; Stresses; Thermal degradation; Thermal fatigue; Thermal stresses; Tire treads; Wheel rims; Wheels
• Identifier Terms: Metroliner (Express train)
• Uncontrolled Terms: Crack propagation; Observations
• Old TRIS Terms: Rapid transit railways; Thermal cracks; Tread braking; Wheel defects; Wheel metallurgy; Wheel thermal stresses; Wheel tread stresses
• Subject Areas: Public Transportation; Railroads; Vehicles and Equipment;

Filing Info

• Accession Number: 00154804
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: 10-D-033(018-2) Final Rpt., FRA/ORD-77/17
• Contract Numbers: DOT-TSC-712
• Files: NTIS, TRIS, USDOT
• Created Date: Jun 17 1981 12:00AM