Stress-strain behavior of rail fastenings in railway turnouts

This paper investigates the stress-strain behavior of rail fastening systems in railway turnouts subjected to non-uniform stiffness distribution and cyclic axial wheel loading. Unlike conventional track sections, turnout fastening units exhibit structural asymmetry and complex load transfer mechanisms that significantly influence stress evolution and deformation response. A three-dimensional finite element model was developed to analyze the behavior of switch slide chairs under loading applied separately to the stock rail and the switch rail. The analysis determined maximum deflections of 4 and 5 mm for the stock-rail and switch-rail loading cases, respectively, and identified critical stress states from +200 to –433 MPa that may contribute to fatigue-related damage under repeated service conditions. The results demonstrate that under-rail pad stiffness substantially affects stress redistribution and the durability of fastening nodes. Based on these findings, recommendations are proposed for refining stiffness parameters to enhance the reliability and service life of railway turnouts.