Switzerland's $2BN Tunnel U-Turn

TL;DR

Switzerland's second Gotthard road tunnel hit a $25M setback when a TBM got stuck in fractured rock just 200m in, forcing a method switch.

Key Points

• 1.The second Gotthard road tunnel is being built to allow renovation of the original, not to increase capacity. Swiss Federal Constitution Article 84 prohibits increasing Alpine transport route capacity, so both tunnels will carry one-directional traffic only.
• 2.Two TBMs — Alisandra (north) and Paulina (south) — are boring a 17km tunnel simultaneously. Both machines exceed 12m in diameter and were expected to meet in the middle by 2027.
• 3.Paulina got stuck less than 200m in after hitting highly fractured loose rock and cavities. The cutter head became blocked with insufficient torque to turn, causing the tunnel face to collapse.
• 4.The rescue operation involves digging an extra access tunnel to free Paulina from the front, expected to take until spring 2026. The setback adds ~20 million Swiss Francs ($25M USD) to the $2.7 billion total project cost.
• 5.Known fault zones like the 400m Goopis shear zone were always planned for conventional drill-and-blast, but this collapse zone was misjudged. Geology data was largely inherited from the original 1970s tunnel analysis, and the hazardous area was positioned differently than predicted.
• 6.The project features two unique engineering decisions: high-voltage power lines routed through a service duct (a European first) and 7.5 million tons of excavated rock reused — half sent 50km to Lake Lucerne to create shallow-water wildlife habitats.