The influence of precise tamping mode on mechanical and geometric characteristics of railway ballasted track

The precise tamping mode plays a crucial role in determining the maintenance effects on railway ballasted tracks. Previous studies have focused separately on either the mechanical response or the geometric evolution of tracks, which limits their applicability to onsite maintenance practices. To address this gap, the first optimization study on the precise tamping mode was performed by incorporating both the mechanical and geometric characteristics of the track. A ballast bed–maintaining model was developed using the discrete element method (DEM). On this basis, the influence mechanisms of various maintenance modes on the mechanical behavior of the ballast bed were investigated, revealing the evolution laws of key mechanical indicators, including the lateral resistance, longitudinal resistance, support stiffness, and compactness of the ballast bed. Furthermore, field experiments were conducted, and on the basis of the track geometry inspection data, the improvement effects and deterioration rates of track quality under different maintenance modes were analyzed. The results showed that when the average lifting amount of the working section was less than 20 mm, the tamping + stabilizing (TS) or unilateral double tamping + stabilizing (DTS) mode was recommended; when the average lifting amount exceeds 20 mm, the DTS or tamping + tamping + stabilizing (TTS) mode was preferred.