To investigate the effects of combined track gauge adjustment and rail grinding on the track state and vehicle dynamics of a mixed passenger and freight railway trunk line The state of rails, geometric parameters of tracks, and vehicle dynamics performances before and after track work in the experimental section were compared and analyzed. The results showed that the rail state was, and the personalized grinding eliminated the rail surface diseases, and no diseases occurred again within 6 months after grinding. The contact status between wheel and rail and the equivalent conicity were improved. The geometric parameters of the track were improved, and the gauge dynamic TQI decreased from 0.76 to 0.31 and 0.4 after the precise gauge adjustment and 3 months later, respectively. The gauge static TQI decreased from 0.7 to 0.15. The vehicle dynamics performances improved, and the maximum values of the transverse and vertical vibration acceleration of the EMU bogie decreased by 30.58% and 34.04% respectively. The derailment coefficient and the rate of wheel load reduction were significantly reduced, and the maximum values of the transverse and vertical vibration acceleration of the track inspection vehicle decreased by28.57% and 21.62%, respectively. Simultaneous implementation of rail gauge fine adjustment and rail grinding can significantly improve track quality and the dynamic performance of EMUs, ensuring the safety and ride comfort of train operation.