This research evaluates the fatigue assessment of an old riveted railway bridge, which is defined as an archetype of the Chilean railway portfolio. The superstructure is assumed to have been built in 1910, with a retrofitting applied during its service life to ensure serviceability and improve load-carrying capacity. The bridge and subsequent retrofitting are defined following a statistical analysis of historic railway bridges in Chile, and they are intended to represent a group of structures with similar characteristics. The loading spectrum used to assess fatigue is based on historical and current data on freight locomotives and frequency, representing the actual loading conditions of Chilean railway bridges. The bridge type in all its configurations is modelled as different numerical FE models with frame elements and continuous joints between the stringer-to-floor beam and bottom chord-to-floor beam connections. A fatigue analysis is performed on the stringer-to-floor beam connections using the detailed loading spectrum and S-N curve category 71 provided in Eurocode 3. The accumulated fatigue damage is determined by applying Miner´s rule. The results show that the retrofitting applied to the bridge type affects the locations prone to fatigue. Moreover, the retrofitting applied to the archetype bridge is able to withstand cyclic loads from modern trains, reaching a maximum accumulated fatigue damage of less than 36.5% of the total fatigue life. Furthermore, it is concluded that the use of the bridge typology is an efficient approach to assess fatigue damage and may help save historical bridges from being replaced from the railway network.