Abstract Masonry bridges are common throughout the transportation networks of many European countries, with further impressive examples found around the world. Maintaining these bridges is becoming a critical task, to preserve not only architectural heritage but also the historic embodied carbon that was invested in their construction, at a time when society’s CO2 emissions must be drastically reduced. In this context, sensing technologies can offer vital information to structural engineers seeking to extend the working lives of such bridges. This presentation will describe novel installations of Fibre-Bragg gratings (FBGs) at masonry railway bridges in the UK, where FBGs have been used alongside other technologies (Acoustic Emission, Videogrammetry, and advanced analysis of Laser Scan data) to characterise the bridge responses, including multi-dimensional movements across cracks. These cracks are of particular concern to asset engineers. Responses to common train types will be presented, including heavy freight trains which may be key drivers of deterioration. Following this, the distributed nature of the bridges' structural behaviour is interpreted, alongside trends in behaviour with train speed, temperature, and time. These results validate the ability of FBG monitoring to track complex masonry bridge degradation, which is required until planned strengthening or renewal works can be undertaken, and shed light on the multi-dimensional behaviour of skewed masonry arch bridges and viaducts.