In recent years, increasing attention has been paid to the impact of vibrations generated by operating subway trains on the surrounding environment. However, the dynamic response occurring below the moving load of the train remains poorly understood, presenting a highly complicated issue. To address this challenge, a 2.5-dimensional finite element method was applied, aimed at calculating and predicting the vibration and deformation of subway tunnels and foundations swiftly and accurately. Specifically, this study focused on analyzing the vibration characteristics of the rectangular tunnel in Ningbo Rail Transit Line 3 (Zhejiang Province, China). The analysis evaluated the influence of key factors—including tunnel burial depth, foundation soil properties, and train speed—on vibrations in the tunnel’s foundations and tracks under operational loads. Results indicated that higher train speeds, shallower tunnel depths, and lower soil shear wave velocities correlated with increased ground vibration intensity. This study offers valuable tools and insights for predicting ground vibrations and potentially enabling early warnings in the future.