Purpose <p>To reduce the dynamic model size of bridge-track systems, a generalized formulation suitable for the reduced-order modeling of systems with three sequentially connected linear substructures is first proposed in this paper. Subsequently, a novel model order reduction method specifically designed for bridge-track systems is derived based on this formulation.</p> Methods <p>The generalized formulation is first derived based on the free-interface component mode synthesis method, extending its applicability to model order reduction for systems with three sequentially connected linear substructures. Then, a reduced-order model (ROM) of the bridge-track system is established by retaining all degrees of freedom (DOFs) of the track structure while truncating the bridge structure DOFs. Case studies including a multi-beam system and a bridge-track system with linear or nonlinear connection conditions are conducted to validate the accuracy of the proposed model order reduction method.</p> Results <p>The results obtained from both finite element (FE) analysis and the proposed model order reduction method demonstrate good agreement in the case studies. For the multi-beam system case study, the proposed method achieves significantly lower computational time compared to the conventional FE analysis.</p> Conclusion <p>Compared to the FE analysis, the proposed model order reduction method significantly reduces the model size while preserving the simulation accuracy in both the multi-beam and bridge-track systems with linear or nonlinear connections.</p>