Mathematical modelling and dynamic characteristics analysis of railway stabilizing operation on different status ballasted track railways

This study investigates the dynamic characteristics of railway stabilizing operations on overhauled, newly-built and repaired railways, which are crucial for developing intelligent operation modes for dynamic track stabilizer vehicles (DTSVs). The research presents a novel comprehensive dynamic mathematical model and a ballast bed parameter identification strategy based on the discrete element method (DEM), representing the first systematic approach to simulate stabilizing operations across various ballasted track conditions. This work develops a dynamic track stabilizer vehicle-track spatial coupling dynamics model (DTSV-TCDM) and employs DEM to establish computational models of overhauled, newly-built and repaired ballast beds. Furthermore, it introduces an innovative identification methodology that combines frequency response function (FRF) with nonlinear ordinary least squares optimization (OLS) to identify ballast bed dynamic parameters. The proposed DTSV-TCDM and DEM models undergo careful validation through multibody dynamics (MBD) simulations and field tests, respectively, while a DTSV-SIM simulation system is implemented to analyse stabilizing operation dynamics. The results demonstrate that excitation frequency exerts a predominant influence on railway stabilization effectiveness, whereas downward pressure and operation speed exhibit comparatively minor effects on system dynamic behaviour. The analysis suggests optimal stabilization parameters within the ranges of 25–40 Hz for excitation frequency and 5–9 MPa for downward pressure, with controlled operation speed being essential for maintaining stabilization quality. Furthermore, the investigation reveals an effective stabilization range of approximately 6–8 m, with particularly efficient vibration transmission characteristics observed between stabilizer and sleepers when operating within the 30–40 Hz frequency band. These comprehensive results provide both theoretical foundations and practical guidelines for optimizing railway stabilizing operations in engineering applications.