Abstract: With the rapid development of urban rail transit, the seismic safety of the tunnel-track system remains critically important. Most existing studies overlook the interaction between the track structure and the tunnel, which limits accurate assessment of the tunnel-track system’s seismic response. In this paper, a three-layer beam-spring model comprising rails, composite slabs, tunnels, and a Winkler foundation is established based on elastic foundation beam theory. The dynamic response of the tunnel-track system under vertical seismic action is solved using Duhamel integral and Fourier series expansion. The analytical solution’s accuracy is verified through comparison with numerical simulation results. Parameter analysis is then conducted on four aspects: foundation spring stiffness, tunnel lining stiffness, rail-composite slab connection stiffness, and composite slab-tunnel connection stiffness. Results show that increasing foundation spring stiffness significantly reduces the peak response of each beam layer. Increasing tunnel lining stiffness causes peak displacement response to increase initially and then stabilize, while peak rotation angle exhibits a gradually increasing trend. Rail-composite slab connection stiffness has a minimal effect on the system’s peak seismic response. Enhancing composite slab-tunnel connection stiffness reduces the peak seismic response of rails and composite slabs but does not significantly affect the tunnel’s peak seismic response.