At first glance, the two portals framing the former ticket hall of Frankfurt (Main) Central Station look like solid masonry arch constructions of enormous dimensions. But behind the elaborately designed visible façades are two structures, which are unique testimonies to the engineering achievements of their time and are impressive in their technical design. The two portals, including their non-visible structural elements, were examined with regard to their current condition and damage and recalculated using ANSYS simulation software. Computational parameter studies using 3D models were required in addition to a thorough inspection of plans from the time of construction, precise manual examinations, non-destructive testing methods and local exploratory openings. In the case of the city-side portal, this simulation made it possible to qualitatively reconstruct the various, complex construction and renovation phases of the previous century, including the associated damage and stress states. The analysis has shown that both arches have a low stress level in the undeformed state. However, due to the design of the arches, they are parti-cularly sensitive to deformation of the supports. Based on current knowledge of the condition of the structure, there are no doubts about sufficient residual safety until the planned repairs are carried out. Yet further deformations in the context of future construction work must be prevented and, where not possible, reduced to a minimum. However, a well-founded approach and the implementation of a detailed and careful repair concept enable the preservation of these unique structures.