Sensitivity analysis of additional temperature stresses in continuously welded rails on a bridge as a function of track longitudinal resistance

This study investigates the sensitivity of additional temperature stresses in continuously welded rails on a bridge, using a railway viaduct with a span of 10×30 m as an example. The aim of the analysis is to quantify the influence of track longitudinal resistance on the distribution of temperature stresses arising from the thermal track/bridge interaction. Track longitudinal resistance represents a key parameter in the behavior of continuously welded rails on a bridge. Numerical models were developed using the finite element method, and the calculations were performed in accordance with relevant European standards and guidelines, including UIC Code 774-3. The study examined track longitudinal resistance under summer and winter conditions, the application of reduced resistances in rail fastening systems, as well as the ZLR (Zero Longitudinal Restraint) system. Special attention was given to the influence of these variations on the control of track lateral stability in summer conditions, as well as on the control of rail break gap in winter conditions. Both checks are of critical importance for railway safety. The results show that variations in track longitudinal resistance cause significant changes in the distribution of temperature stresses, highlighting the need for careful design and optimization of track components on a bridge. The findings contribute to a better understanding of thermal track/bridge interaction and provide a basis for improving the design of railway viaducts with continuously welded rails.