Statistical running safety analysis of high-speed trains on beam bridges after long-term service

The evolution of high-speed railways has shifted from extensive construction to long-term, secure operation. Over time, these railways face structural deformations due to specific geographical and environmental factors, impacting track smoothness and train running safety. This research examines the long-term service-induced bridge deformations' effect on high-speed train safety. A coupled dynamic system is established, encompassing high-speed trains, tracks, and bridges. In this model, initial track irregularities are treated as a stochastic process, combined with track deformations resulting from bridge deformations. Statistical parameters for the system's response are calculated utilizing a new point estimation method. Based on safety and comfort control criteria for high-speed train operations, the effects of different forms of bridge deformations are discussed, as well as their combined influence on train performance. The results reveal that lateral bridge deformations significantly affect train performance, more so than vertical deformations and should receive greater attention in practical engineering. Additionally, train performance indices increase with greater beam deflection and lateral displacement. Lastly, variations in the impact of high-speed trains on long-serving high-speed railway bridges under different operating speeds are explored. The calculated findings illuminate the intricate dynamics of high-speed trains crossing deformable bridges, underscoring the need for comprehensive bridge deformation consideration in safety assessments.