The paper deals with the challenge on structural analysis, logistics as well as on geotechnical aspects during sinking of an approximately 60 m deep construction shaft with a cross-sectional area of about 720 m 2 at the Koralm Tunnel lot KAT 2. Numerical 3D simulations were used for the structural analysis. The results in terms of level of loading of the support measures and the displacements served as a basis for predicting the system behaviour of the shaft. During sinking, the behaviour of the shaft and surface was continuously monitored within the geotechnical safety management by means of 3D displacement measurements, measurement of strains in the shotcrete lining and measurements of pile inclinometers. Thereby a continuous target-performance comparison was accomplished. Special characteristics in the design and construction phase are illustrated and discussed.

The ÖBB‐Infrastruktur AG operates and maintains 246 tunnels and similar structures with an overall length of approx. 250 km. Nearly 150 of these structures are more than 100 years old, 35 of them are over 150 years old. Ageing processes, the impact of train traffic, ground conditions and environmental conditions are causing progressive damage to the tunnel linings, which – in order to maintain safe railway operation – requires ongoing maintenance procedures. Those procedures are carried out under a range of restrictions concerning availability, which is one of the most important principles at the ÖBB after safety. In order to obtain continuous availability of the facility, new methods of refurbishment were developed for the two double‐track tunnels Rekawinkler Tunnel and Kleine Dürreberg. The described methods enabled extensive repair works of the tunnels, mostly with uninterrupted train traffic on the second track.