Abstract: Utilizing large tamping vehicles to maintain the ballasted track is the most effective method and general mean to improve the quality of ballast bed, which is also the inevitable choice to ensure the safety of train operation. However, the large maintenance machinery in China originates from the foreign technology, which leads to insufficient understanding of the tamping operation mechanism of tamping vehicles and makes it impossible to carry out scientific maintenance. To improve the understanding of the operation process of the three-sleeper tamping machine of DWL-48 tamping and stabilizing vehicles commonly used in railway maintenance, a three-dimensional fine coupling simulation model of three-sleeper tamping machine-track row-ballast bed was established using discrete and multi-body dynamics collaborative simulation analysis method. The correctness of the model was verified by the field experimental results. The translational and rotational characteristics and energy evolution of ballast particles in the dynamic process of tamping operation were analyzed. The result shows that the impact of tamping picks on the translation, rotation and energy of ballast particles is mainly located in the area 0 mm-175 mm below the sleeper. The variation law of ballast particle velocity and angular velocity has good synchronization, which facilitate quickly filling the gap under the sleeper. During the tamping operation, the tamping pick fills the gap under the sleeper in the way of “mainly translation, secondary rotation”, with gradual evolution of the translational kinetic energy and rotational kinetic energy of ballast particles to the potential energy.