Breakthrough Achieved on Gotthard Second Tube Northern Section

Why It Matters

The breakthrough accelerates completion of the second Gotthard tube, enhancing cross‑border freight flow and road safety on Europe’s busiest Alpine route. It also showcases advanced TBM technology capable of handling extreme rock conditions, setting a benchmark for future infrastructure projects.

Key Takeaways

• Alessandra TBM broke through after 3.8 km of Alpine tunnelling
• Advance rates reached up to 32 m per day in hard rock
• 15 cutterhead motors deliver 5,250 kW, thrust up to 95,000 kN
• Second tube will boost safety and capacity on trans‑Alpine route

Pulse Analysis

The Gotthard Road Tunnel, Switzerland’s flagship trans‑Alpine link, has operated as a single bore since 1980, handling millions of vehicles each year. To meet growing traffic and stringent safety standards, the Federal Roads Office commissioned a parallel 6.9‑km tunnel, dubbed the second tube. Construction began in February 2025, with the northern drive launched from Göschenen. The recent breakthrough marks the first major connection between mechanised and conventional excavation zones, clearing a critical bottleneck in the project’s schedule and paving the way for continuous southward boring.

At the heart of this milestone is "Alessandra," a 12.2‑meter single‑shield TBM supplied by Herrenknecht. Powered by fifteen cutterhead motors delivering a combined 5,250 kW and a thrust capacity of 95,000 kN, the machine has demonstrated remarkable resilience in granite, gneiss and quartz‑rich formations. Its peak advance of 32 meters per day rivals the best performances in Europe, despite heightened cutter wear in blocky granite sections that required frequent disc‑cutter swaps. The TBM’s ability to maintain momentum under such conditions underscores the maturity of modern tunnel‑boring technology and offers valuable data for future projects confronting similar Alpine geology.

Beyond engineering triumphs, the second tube carries significant economic and safety implications. Doubling the tunnel’s capacity will alleviate congestion on a corridor that moves over 20 million trucks annually, reducing transit times and emissions across the continent. Enhanced safety features, including separate evacuation routes, align with EU directives on tunnel risk mitigation. For contractors Implenia and Frutiger, successful delivery strengthens their reputation in large‑scale infrastructure, potentially unlocking new contracts in Europe’s ambitious rail and road expansion plans. As the TBM resumes its southward push, the Gotthard project stands as a benchmark for high‑performance tunnelling and a catalyst for smoother, safer European freight movement.