Kaiserstuhl Tunnel reaches breakthrough
A major milestone has been reached on the Kaiserstuhl Tunnel project. After around 2 years and 2 months of excavation, the tunnel breakthrough took place on 10 September 2026.
The approximately 1,560-metre tunnel was excavated from the north using drill-and-blast methods. From the southern portal, an additional 185 metres were excavated through soft ground, requiring a different approach to ensure safe and stable construction.
Geological challenges encountered during the northern excavation led to delays and required adjustments to the construction strategy. To optimise the construction programme, the final 35 metres were excavated from the southern heading using machine-assisted excavation in rock, bringing the two tunnel sections together and enabling the breakthrough.
Reaching this milestone is an important step forward for the Kaiserstuhl Tunnel project. It reflects the dedication, expertise and close coordination of the teams involved, who worked together to overcome the challenges encountered during construction.
With the breakthrough now achieved, the project moves into the next important phase towards completion of the tunnel.
