Technology Digests / Lateral Track Strength in Recently Misaligned Track

TD24-025

June 25, 2025
Authors
  • Stephen Wilk
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Key Findings

  • Recent alignment deviations can reduce track buckle strength both from a geometric standpoint and from a reduction in lateral track strength.
  • In compacted track, recent deviations of 1 inch or greater can reduce lateral track strength by up to 20 percent.
  • Alignment deviation strength loss is affected by pre-misalignment compaction, post-misalignment compaction, misalignment length, and misalignment magnitude.
  • Train operations after the formation of an alignment deviation will restart the compaction process.
  • Alignment deviations in partially compacted track produce strength reductions of less than 20 percent but represent the lowest lateral track strength because the surrounding track is only partially rather than fully compacted.

Lateral Track Strength in Recently Misaligned Track

MxV Rail conducted Single Tie Push Tests (STPTs) at the Facility for Accelerated Service Testing (FAST®) in July 2024 to better understand whether tie movement can cause a tie to temporarily revert to a “disturbed” state of reduced lateral track strength, similar to the strength after tamping. This Technology Digest presents the test data that focuses on recent alignment deviations, but the data can be applied to other situations when longitudinal rail forces can pull a curve in or push a curve out (i.e., curve breathing). This work was supported by the Association of American Railroads (AAR) under its Strategic Research Initiatives Program. BALLAST DISTURBANCE  Over the past few years, MxV Rail has conducted multiple tests investigating how tamping and subsequent tonnage, or dynamic track stabilizers, affect lateral track strength.1,2,3 These tests are important for ensuring the track remains in proper alignment and in a stable condition. Track buckles often…