Technology Digests / Concrete Tie Life from Inspection Data

TD23-022

November 21, 2023
Authors
  • Dustin Clasby
  • Stephen Wilk
  • Yin Gao
  • Adam Bankston
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Key Findings

  • Of nearly one million analyzed concrete ties installed in the last 20 to 40 years and still in service; 90 percent are currently in “good” condition and about 1 percent are in “bad” or “failed” condition with the remainder categorized in “marginal” condition. An estimated six percent of the ties have been replaced.
  • In track segments that have not yet received replacement ties, an estimated three out of four concrete ties installed will remain in “good” condition after 2,800 to 5,280 million gross tons (MGT) (40-75 years at 70 annual MGT). In comparison, for ties installed in track segments that have already received replacement ties, the same three out of four “good” tie condition metric is estimated to be between 700 and 1,000 MGT (10-14 years). This difference suggests that concrete ties in a more demanding load environment experience accelerated degradation and a shorter lifespan.
  • “Bad” and “failed” concrete ties tend to be bunched together in groups—further suggesting that tie life is a function of the load environment, which in turn can be affected by a wide range of potential factors.

Concrete Tie Life from Inspection Data

MxV Rail analyzed the condition of more than one million concrete ties, using track inspection data collected in 2022 over five subdivisions from one railroad in the western United States. The four preliminary goals of this study were to: 1) identify the current range of tie conditions within the five subdivisions, 2) develop useable definitions of “tie life” from large datasets, 3) estimate the observed range in concrete tie life, and 4) identify the factors that may affect tie life. This Technology Digest has a companion publication1 focusing on the relationship between track condition and degraded concrete ties. Beyond the preliminary goals, the larger, more long-term goals of this study are to better define tie life (along with the parameters that affect it) and to identify track maintenance practices that may extend tie life. However, additional datasets and physical testing are necessary to answer many of these larger questions. This…