A significant moment for the cross-border Brenner Base Tunnel railway infrastructure project: after around 26 months of continuous work, the tunnel boring machine Ida successfully completed the first breakthrough of the main tunnel tube on the Austrian side on August 22, 2025. But there has been a lot more going on at the various construction sites of this mega-project in recent months.

For more than 20 years, the six tunnels of the Semmering tunnel chain on the S 6 have been the fastest and, above all, safest connection between Styria and Lower Austria. However, it is now necessary to modernize the tunnels both structurally and in terms of technical equipment. Since April 28, 2025, the 21 kilometers of tunnels (10.5 km in each direction) are being completely renovated.

In June 2025 Implenia has signed an “Early Contractor Involvement” contract with Swedish company SKB (Svensk Kärnbränslehantering AB) to build the first underground section of a deep repository for radioactive waste near the Forsmark nuclear power plant in Eastern Sweden.

It is an ambitious plan set to revolutionize the Paris transportation network: The realization of the Grand Paris Express includes the extension of an existing metro line (Line 14) and the construction of four new metro lines in the inner and outer ring zones (Lines 15, 16, 17, and 18). Completion is planned for 2030, but even in the early construction phases, it became clear: this is no ordinary infrastructure project. Line 17, in particular – intended to connect northern Paris with Le Mesnil-Amelot – posed major challenges for the engineering and construction team.

In late June 2025, the last of two Herrenknecht Single Shield TBMs successfully completed its drive for the new railway line between Rishikesh and Karnaprayag in the Indian Himalayas. The first machine had already reached its destination in mid-April. Now both parallel tubes of the more than 20-kilometer-long tunnel system are complete.

On May 22, 2025, the 10th Rock Mechanics and Tunnelling Day took place in Weinheim, Germany. The large number of registrations exceeded the capacity of the large lecture hall at the WBI Center in Weinheim this year. 320 visitors registered for the specialist event to attend the high-calibre, practice-oriented presentations by more than 20 experts from the fields of rock mechanics and tunnel construction.

The Münster Tunnel Construction Colloquium in May 2025 was a great success and received consistently positive feedback from participants. In a relaxed atmosphere, the fully booked event at the Münster University of Applied Sciences provided experts from the tunnelling profession with a valuable platform for in-depth technical discussions.