Railway bridges are not just functional engineering works; they are historical artefacts that embody technological, economic and political developments of their time. Throughout the operational life of such structures, they are subject to frequent repairs, modifications, and reinforcements. The motivation for such interventions is complex, being influenced by structural necessity, changing demands for mobility, economic conditions, and political decisions regarding the expansion and modernisation of the railway system. This study explores the transformation histories of selected railway bridges on the Leipzig–Dresden line. The research is grounded in a systematic evaluation of archival material, including original plans and construction files, supplemented by historical photographs, technical reports, and published sources of the time they were built. For each bridge, an integrated narrative of structural and contextual changes is reconstructed. By comparing this set of bridges, we can see the changes that happened to them over time. This helps us to understand how the whole system changes. Diagrams are used to show these processes visually and to make it easier to see how they all fit together. These visualisations show not only how changes in the railway system are planned, but also how the wider society and politics influenced these changes. For example, the arch bridges on the Leipzig–Dresden line from the 1840s held up for over 150 years. They were continuously repaired, but almost all of them were replaced in the 1990s. This can be explained by the expansion of the line as one of the German Reunification Transport Projects, which was a political and social issue. The study helps us to understand railway bridges as structures that are always changing. Combining historical analysis with structural documentation helps to interpret infrastructure as part of long-term cultural and technological change.