Operational Vertical Bending Stresses in Rail: Real-Life Case Study

Abstract

Train-mounted vertical track deflection (VTD) measurements offer new opportunities for estimating rail bending stresses over long distances. The estimations are possible because of mathematical correlations among rail deflections, rail stresses, and the loads applied to the rail. Previous numerical studies conducted by the authors resulted in a methodology that suggests the use of finite-element models to develop the correlations. These models facilitate the simulation of a stochastically varying track modulus along the track and provide a strong basis for interpreting the deflection data. In this study, data sets collected from a study site were used to validate this methodology for estimating rail bending stresses under passing train loads. The rail-mounted strain gauges and the wheel impact load detector system at the study site provided information about the rail bending strains under known applied loads. This allowed validation of the maximum bending stresses estimated using train-mounted deflection measurements. The magnitude of rail bending stresses was assessed using measurements from different seasons; stress changes over time were also investigated.