Nonlinear buckling analysis of curved railway tracks considering unbalanced cant and train speed.

Elevated rail temperatures can induce axial compressive stresses in continuous welded rail (CWR). If the rail temperature exceeds critical limits, it leads to track instability and an increased risk of derailments. The focus on curved tracks is critical, as these are particularly susceptible to buckling under high temperatures. When trains approach these curves, additional multidirectional forces are introduced, exacerbating instability risks. This study investigates the nonlinear buckling behavior of curved railway tracks under elevated temperature, focusing on the combined effects of the cant and varying train speeds. Unbalanced train speed refers to the situation where a train travels at a speed that is either too fast or too slow for the design of the track's radius and cant. Such speeds introduce lateral forces that can compromise track stability. It can increase the risk of lateral displacement, especially when combined with increased temperature. These forces can result in complex, nonlinear buckling behavior, which remains insufficiently understood. To analyse these risks, we conducted a buckling temperature analysis using nonlinear three-dimensional finite element method (FEM), specifically tailored to curved railway tracks. Track variables such as radius, lateral resistance, cant, and initial misalignment were incorporated to comprehensively understand the thermal challenges faced. The results highlight the critical temperature thresholds at which buckling is most likely to occur and provide insights into how the temperature and train speed exacerbates track instability. These findings provide valuable guidelines for the design, maintenance, and train speed adjustments on curved tracks, enhancing safety and performance under extreme conditions.