Fracture Mechanics Approach to Estimate Rail Wear Limits

Abstract

This paper describes a systematic methodology to estimate allowable limits for rail head wear in terms of vertical head-height loss, gage-face side wear, and/or the combination of the two. This methodology is based on the principles of engineering fracture mechanics. The concept of applying the principles of engineering fracture mechanics to examine structural integrity was originally introduced by the U.S. Air Force, and is now embraced by the commercial aircraft industry. Aircraft structures are based on fracture mechanics (also referred to as damage tolerance) principles. Moreover, the approach in conducting rail integrity research sponsored by the Government is based on damage tolerance principles. The fracture mechanics methodology to estimate rail head wear limits is based on various assumptions regarding operational and environmental factors. These factors include rail size, foundation modulus, temperature difference, train speed, and rail test interval (i.e. tonnage between rail tests). This paper describes the methodology based on engineering fracture mechanics to estimate rail wear limits. In addition, results and sensitivity studies from applying the methodology are presented.