Corrugated steel culverts are sometimes used as an alternative to portal frame bridges for small and medium crossings under railway lines. From a static point of view, the corrugated steel culverts are rather flexible structures and the load capacity relies on the confinement from the surrounding soil. From a dynamic point of view, especially for potential use on high-speed lines, the structural manner of action is not yet fully explored. This paper presents the result from full-scale experimental testing of a corrugated steel culvert, including both forced vibration tests and response from passing trains. The aim is to estimate the dynamic characteristics of the bridge, especially the interaction with the surrounding soil and how that will influence the response at the track level. From the forced vibration tests, the results show that the structure has a high inherent damping owing to the surrounding soil and that both the natural frequency and damping change with load amplitude. The experimental frequency response functions are used for updating numerical models to further understand the dynamic behaviour of these structures.