The subject of this study is the inventory and assessment of the load-bearing capacity of a railway bridge. The analysis was conducted on a bridge with a concrete slab reinforced by steel beams as the load-bearing element. The structure is located in the village of Bukowina, Warmian-Masurian Voivodeship, Poland. The aim of the study is to assess the load-bearing capacity of the bridge. The structure’s geometry was measured, and its concrete strength class determined. This article presents the results of stress limitation calculations for the tested bridge. Three calculation procedures based on two approaches—a concrete-encased beam and a bending section reinforced with rigid inserts — were applied. The analysis demonstrated that, despite the unesthetic appearance of the bridge, it meets the stress limitation requirements. Though over a hundred years old, the structure remains suitable for use today.