In Airolo (Ticino), the Marti 2TG Consortium—comprising Marti Tunnel AG, Mancini & Marti SA, and Ennio Ferrari Impresa Generale SA—launched TBM Paulina. This Single Shield TBM has a 12.31-meter diameter, weighs 2,500 tons, and is 100 meters long, with a 5,600 kW main drive. It will bore 7,755 meters through the Gotthard mountain range, constructing the southern section (Lot 341) of the 16.9 km second tube of the motorway tunnel.
Designed to handle the hard rock of the Alps, TBM Paulina will navigate through granite, gneiss, and slate. Marti Tunnel AG previously completed excavation of the southern access tunnel (Lot 343) in August 2023 using a Herrenknecht Single Shield TBM (Ø 7.4m). ARX, leading the Bedrina Joint Venture, is overseeing the supervision of the southern section’s construction.
Northern Section – TBM Deployment in Göschenen
Meanwhile, in Göschenen, the Implenia Schweiz AG & Frutiger AG Consortium launched another Single Shield TBM (12.225-meter diameter, 5,250 kW main drive) to excavate 6,885 meters of the northern section (Lot 241). This consortium had previously completed the northern access tunnel (Lot 243) in April 2023 using a gripper TBM (Ø 7.03m) named Carla, also supplied by Herrenknecht.
Project Timeline & Challenges
Both TBMs will advance 7 to 8 kilometers before reaching their final destinations. Along the way, they will cross a 350-meter-long geological fault line, which will be excavated using conventional methods.
With an average progress rate of 18 meters per day, the TBMs are expected to meet at the center of the tunnel by spring 2027. The breakthrough ceremony is planned for autumn 2027, and the tunnel’s second tube is scheduled to open to traffic by 2030. Following its completion, work will begin on refurbishing the existing Gotthard Tunnel tube.
For further information please click here and ch/50 for the tunnelbuilder archive. Also log on to https://www.astra.admin.ch, https://gotthardtunnel.ch/, https://www.marti.com/en/, https://www.pini.group/, https://implenia.com/ and https://www.frutiger.com .
