Technical Reports

Estimation of Rail Wear Limits Based on Rail Strength Investigations

  • 01
  • Dec
  • 1998
AUTHOR: David Y. Jeong, Yim H. Tang, and O. Orringer
OFFICE: RPD
REPORT NUMBER: DOT/FRA/ORD-98/07
SUBJECT: Track, Tracks & Structures, Track/Train Interactions
KEYWORDS: detail fracture, dynamic load factor, fracture mechanics, fracture strength, gage-face wear,
ABSTRACT: This report describes analyses performed to estimate limits on rail wear based on strength investigations. Two different failure modes are considered in this report: (1) permanent plastic bending, and (2) rail fracture. Rail bending stresses are calculated using the classical theory of beams on elastic foundation. The effect of wear is modeled as a geometric change of the rail section due to loss of material from wear. Two different wear patterns are examined: (1) vertical railhead height loss, and (2) gage-face wear from the side of the rail (referred to as gage-face side wear). An elementary plastic-collapse criterion is used to estimate wear limits based on failure by means of rail bending. An approximate method that was previously developed to analyze the growth of internal transverse defects is also applied to estimate wear limits on the basis of fracture strength. These analyses reveal that rail-wear limits estimated with the fracturemechanics approach are more restrictive (i.e., conservative) than those based on the plastic-bending approach. Therefore, for safe operations on railroad tracks, allowable rail-wear limits should be estimated on the basis of fracture strength.

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