Temperature-Induced Cyclic Loading Effects on Rail Anchor Slip Force

Recently, continuous welded rail (CWR) systems have been widely adopted due to their enhanced ride quality, reduced maintenance requirements, and extended service life for both rails and rolling stock. However, the elimination of joints in CWR introduces challenges, particularly in managing thermal expansion, which can lead to track buckling. A critical factor in maintaining track stability is the Rail Neutral Temperature (RNT) — the temperature at which rails are free of thermal stress. Anchors, which resist longitudinal rail movement, play a key role in managing RNT and ensuring track integrity. While previous studies have largely focused on the static behavior of rail anchors, this research emphasizes the importance of cyclic longitudinal loading, which can simulate daily and seasonal temperature fluctuations. Unlike static loading, cyclic longitudinal loading on the rail-anchor under different temperatures can potentially lead to gradual degradation in anchor performance, slip initiation, or cumulative displacement over time. These effects may be more critical to track stability than static forces alone, especially under service operating conditions. This study will conduct full-scale laboratory testing to investigate the impact of cyclic temperature-induced longitudinal loading on slip force performance for various rail anchor types. By simulating temperature cycles and measuring anchor slip under controlled conditions — including different anchor geometries, installation tightness, and environmental parameters — this research aims to provide an understanding of the long-term reliability of rail anchoring systems under thermal cycling. Also, this study addresses the need to construct a 15-foot full-scale track segment on ballast and wood ties to replicate in-field conditions for the future studies to be performed for this project.

• Record URL:
  • https://www.utrgv.edu/railwaysafety/research/infrastructure/index.htm
• Supplemental Notes:
  • MxV Rail and BNSF Railway are partners for this project.

Language

• English

Project

• Status: Active
• Funding: $190,423.00
• Contract Numbers:

  69A3552348340

• Sponsor Organizations:

  Office of the Assistant Secretary for Research and Technology

  University Transportation Centers Program
  Department of Transportation
  Washington, DC  United States  20590

  University of Texas Rio Grande Valley

  1201 W. University Dr
  Edinburg, TX  United States  78539
• Managing Organizations:

  University of Texas Rio Grande Valley

  1201 W. University Dr
  Edinburg, TX  United States  78539
• Project Managers:

  Stearns, Amy

• Performing Organizations:

  University of Texas Rio Grande Valley

  1201 W. University Dr
  Edinburg, TX  United States  78539
• Principal Investigators:

  Rahmaninezhad, S. Mustapha

  Tarawneh, Constantine

• Start Date: 20250601
• Expected Completion Date: 20260831
• Actual Completion Date: 0
• USDOT Program: University Transportation Centers Program

Subject/Index Terms

• TRT Terms: Anchor bolts; Continuous welded rail; Cyclic tests; Railroad safety; Railroad tracks; Thermal contraction; Thermal expansion
• Subject Areas: Maintenance and Preservation; Railroads; Safety and Human Factors;

Filing Info

• Accession Number: 01960678
• Record Type: Research project
• Source Agency: University Transportation Center for Railway Safety
• Contract Numbers: 69A3552348340
• Files: UTC, RIP
• Created Date: Jul 14 2025 7:42PM