Dynamic Wheel-Rail Forces on Mismatched Joints with Ramps

Details

• Creators:
  Marquis, Brian ; Greif, Robert
• Corporate Creators:
  John A. Volpe National Transportation Systems Center (U.S.)
• Subject/TRT Terms:
  • Rolling contact
  • Train track dynamics
  • Rail joints
  • Rail (Railroads)
  • Ramps
  • Force
  • Car wheels (Railroads)
  • Railroad safety
  • Dynamics
• Publication/ Report Number:
  JCR2016-5734
• Resource Type:
  Research Paper
• Geographical Coverage:
  United States
• Corporate Publisher:
  American Society of Mechanical Engineers
• NTL Classification:
  AGR-SAFETY AND SECURITY-SAFETY AND SECURITY ; AGR-INFRASTRUCTURE-Railroads ; NTL-RAIL TRANSPORTATION-RAIL TRANSPORTATION ; NTL-RAIL TRANSPORTATION-Rail Safety
• Abstract:
  The discontinuity between rail ends at a joint creates ; dynamic wheel-rail forces (i.e. high impact forces and wheel ; unloading) that can result in a range of problems including ; wear, deterioration, and early failure of the track structure, its ; components, and passing equipment. The response and ; magnitude of the dynamic wheel-rail forces generated at joints ; depend upon the form of the discontinuity (e.g. battered rail ; ends, ramps, gaps, mismatches, etc.) and the support condition. ; Joints with battered rail ends, which result from degradation ; due to repeated impact loading, have been extensively analyzed ; using closed form expressions developed by Jenkins 1 to ; estimate P1 and P2 impact forces. While appropriate for ; analyzing joints with battered rail ends, P1 and P2 forces are ; not directly applicable to other forms of discontinuity at joints ; such as mismatches in which the rail ends are offset vertically ; when installed. ; Under certain circumstances, railroads are introducing ; ramps (by grinding or welding) to reduce the mismatch ; discontinuity and produce a smoother transition in order to ; mitigate these dynamic wheel-rail forces. In this paper, ; analyses are conducted to estimate dynamic wheel-rail forces at ; joints having ramps and mismatches of various sizes using ; simplified models along with detailed NUCARS models for ; comparative purposes. The Federal Railroad Administration ; (FRA) Track Safety Standards (49 CFR Part213) 2 limit the ; maximum mismatch at joints by Track Class in order to ; minimize the impact forces which deteriorate the track ; structure, its components, and equipment, and may ultimately ; lead to derailment. Parametric studies are conducted to ; examine the effects of ramp length, direction of travel, ; mismatch height, and equipment speed (track class). Plots of ; primary shock-response-spectrum (maximum impact force on ; the ramp), residual shock-response-spectrum (maximum impact ; force after the ramp), and minimum wheel force (i.e. wheel ; unloading) are developed to provide guidelines on ramp length ; (H-rule) in order to control the maximum force by track class.
  More +
• Format:
  PDF
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/12284/dot_12284_DS1.pdf
• File Type:
  [PDF - 3.35 MB]
• Collection(s):
  Volpe Center
• Main Document Checksum:
  urn:sha256:eb4feaa8899498d82facbeda96093ea2f1ab89e9826c08b16963eaf24799413f