An analytical study of rail grinding optimization for rail-head fatigue defect prevention

Abstract

Over the last two decades, the railroad industry has experienced a significant increase in heavy axle loads acting on railroad rails. In addition, railroad operations have been consolidated resulting in the elimination of redundant routes and increased train traffic on the remaining routes. These changes in railroad industry practice have caused an increase in the rate of occurrence of rail head fatigue defects, one potential cause of train derailment. The primary form of maintenance employed by the individual railroads to combat the formation of fatigue defects is rail grinding. Current rail grinding practices involve removal of surface defects and reshaping worn rail, but they do not involve grinding as a means to mitigate internal fatigue damage. In this study, a model for optimizing a grinding schedule which will prevent the formation of internal fatigue defects is proposed. The model includes a statistical representation of wheel loads, a rail head stress analysis, a rail head fatigue analysis, and optimization of a grinding schedule via mathematical programming. Results from using this model indicate that rail grinding might be performed in such a way as to double the useful service life of railroad rail.