In order to study the influence of vehicle conditions on wheel-rail system vibration in surburban railways, a vertically coupled dynamic vehicle-track-tunnel model is established, and the influence mechanism of operating speed, train passenger load, wheelset mass and wheel polygonalization on the vibration response of vehicle, rail and tunnel is analyzed in detail. The research results show that with the train speed increasing from 100 km/h to 160 km/h, tunnel vibration source strength increases from 68.05 dB to 72.06 dB. With the increase of train passenger load, the vertical ride comfort index of vehicles gradually decreases, while the vertical wheel-rail force, rail vertical displacement and acceleration, maximum Z vibration level of the rail, and tunnel vertical displacement gradually increase, while the tunnel vertical acceleration and maximum Z-vibration level remain basically unchanged. Passenger load mainly affects the tunnel vibration response below 10 Hz. Above 10 Hz, the response is governed primarily by wheel-rail irregularities, and the tunnel acceleration level shows no significant differences among no-load, full-load, and overload conditions. Increasing wheelset mass increases the maximum Z vibration level of the rail and tunnel. During routine vehicle maintenance, the excitation frequency of wheel polygonalization should be prevented from coinciding with the wheel-rail system P2 resonance frequency.