Surrogate coupling model for nonlinear dynamics lateral instability of high-speed trains interacting over turnouts

Aimed at the lateral dynamic instability of high-speed trains running over turnouts, a surrogate coupling model of vehicle and turnout interactions has been established to systematically reveal the characteristics of train vibration and dynamic instability based on the theory of vehicle-track coupling dynamics. Through the coupling model rigorously verified by field measurements, the lateral instability of the high-speed trains is investigated considering car-body accelerations and corresponding Sperling indices. In particular, the effects of alignment irregularities and lateral passing speeds on the train instability are highlighted. Our new results exhibit that high-speed trains passing through turnout’s diverging route become laterally unstable below the maximum design speeds when track maintenance adheres to the planned standards. The Sperling index is nonlinearly affected by the track misalignment. The nonlinear train-turnout interaction causes large amplitude vibration of the train’s lateral mobility to exceed allowable limit of 0.9 m/s². Our novel surrogate coupling models enable high-efficient dynamic instability prediction and assessment using track geometry data from routine inspections, thereby improving operational safety of train-turnout interactions.