This thesis investigates the dynamic response of end-shield railway bridges subjected to high-speed train loading, with a particular focus on the role of soil– structure interaction (SSI). The objective is to assess the performance of a simplified 2D modelling approach that can reliably estimate bridge accelerations under resonance conditions, while significantly reducing computational effort compared to full 3D finite element models. Eighteen existing railway bridges with varying span numbers, geometries, and foundation types were analysed. A reference 2D model incorporating impedance functions, validated against experimental data, served as the benchmark. The proposed simplified 2D model introduces the effect of surrounding soil with concentrated springs and dashpots at the abutments and columns foundations, and distributed springs and dashpots at the end-shields.