Estimation of Rail Wear Limits Based on Rail Strength Investigations

摘要

This report describes analyses performed to estimate limits on rail wear based on211u001estrength investigations. Two different failure modes are considered in this 211u001ereport: (1) permanent plastic bending, and (2) rail fracture. Rail bending 211u001estresses are calculated using the classic theory of beams on elastic foundation. 211u001eThe effect of wear is modeled as a geometric change of the rail section due to 211u001eloss of material from wear. Two different wear patterns are examined: (1) 211u001evertical rail-head height loss, and (2) gage-face wear from the side of the rail 211u001e(referred to as gage-face side wear). An elementary plastic-collapse criterion is 211u001eused to estimate wear limits based on failure by means of rail bending. An 211u001eapproximate method that was previously developed to analyze the growth of 211u001einternal transverse defects is also applied to estimate wear limits on the basis 211u001eof fracture strength. These analyses reveal that rail-wear limits estimated with 211u001ethe fracture-mechanics approach are more restrictive (i.e., conservative) than 211u001ethose based on the plastic-bending approach. Therefore, for safe operations on 211u001erailroad tracks, allowable rail-wear limits should be estimated on the basis of 211u001efracture strength.