This paper presents the dynamic monitoring carried out on a 458 m long railway Papagaios Bridge in Brazil. This is a concrete arch bridge built over 60 years ago, which needed repairs. The dynamic monitoring was designed to carry out a structural integrity assessment and to calibrate a numerical model to be used for the structural rehabilitation design. Vibration measurements were carried out on the bridge in selected locations. This paper addresses data analysis, the impact measurements when a train enters the bridge and modal analysis.