Technology Digests / Estimation of Lateral Track Strength from Track Structure Changes

TD23-018

October 24, 2023
Authors
  • Stephen Wilk
  • Dante DeVencenty
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Key Findings

  • Typical ballast maintenance can increase or reduce lateral track strength by about 25 to 50 percent. This value can be higher in situations where the track structure experiences significant changes.
  • Due to uncertainties in the ballast and tie interlocking characteristics, the actual lateral tie resistance value may be difficult to predict without direct Single Tie Push Test (STPT) measurements. However, changes in resistance due to changes in track condition (e.g., maintenance) can generally be estimated.
  • Higher-risk lateral strength situations are difficult to quantify and require further exploration. These situations may include hanging ties, loss of tie-ballast contact from tie movement, large tamping lifts, mud pumping, shoulder cleaning, tie replacement, or other factors.

Estimation of Lateral Track Strength from Track Structure Changes

Using previously collected lateral strength data, MxV Rail has summarized how certain changes to the track structure may increase or decrease lateral track strength. Having sufficient lateral track strength is important for resisting lateral track movement. A more comprehensive understanding of how different track structure conditions will affect lateral strength can inform track buckle risk. The goal of this analysis, summarized here, is to assess the current capability to estimate lateral track strength with regard to changes in track condition, using generally available parameters. In addition, this Technology Digest will provide examples of the change in lateral track strength due to some common ballast maintenance activities. The analysis revealed the existence of knowledge gaps, many of which will be addressed through future testing. This work was supported by the Association of American Railroads (AAR) under its Strategic Research Initiatives (SRI) program. LATERAL TRACK STRENGTH PARAMETERS Lateral track strength is the…