Rothe Erde bearings ensure tunnelling in the second tube of the Gotthard Road Tunnel

Dortmund/Göschenen/Airolo. Preparatory work for the construction of a second tube in the Swiss Gotthard Road Tunnel has been underway since spring 2020. Four tunnel boring machines are carrying out a large part of the central work. Right at the front of the cutterhead in all four tunnel boring machines involved: slewing bearings from Rothe Erde.

The Gotthard Road Tunnel has been running under the mountain massif of the same name since 1980. As the longest road tunnel in the Alps, it connects the Swiss towns of Göschenen and Airolo over a distance of almost 17 kilometers and is one of the most important and fastest Alpine crossings. Only one tube is currently available, through which traffic flows in both directions. “The Gotthard Road Tunnel has been in existence for more than 40 years and traffic has increased significantly since then,” explains Eugenio Sapia, media spokesman for the Swiss Federal Roads Office (FEDRO). Every year, five million cars and an additional 900,000 trucks use the Gotthard Road Tunnel. “With the new construction of the second tube, we are separating the directions of travel and thus ensuring increased safety,” says Sapia. The capacity of the tunnel will not be increased; as before, only 1,000 cars per day will be allowed to use the tunnel, with one truck equating to three cars.

Access tunnels as preparatory work

Drilling has been underway at the Gotthard since 2022. Preparations for the construction of the second tube include the construction of two access tunnels. Two tunnel boring machines with drilling shields with diameters of seven and 7.4 meters were initially used for this. For the construction, the tunnels were driven simultaneously from the north and south in two independent construction phases, so that completion could already be announced in April and August 2023. The second tunnel is being built around 70 meters next to the existing tunnel and is just as long. “For the construction, 7.4 million tons of rock have to be broken out of the mountain massif, which will be used for construction, terrain modelling or renaturation projects, for example,” explains Sapia.

Twelve-meter tunnel boring machines in use since February

The really big machines have been arriving since February 2025: the drill shields of the two larger tunnel boring machines each have a diameter of over twelve meters. Tunnel boring machines of the single-shield TBM type from the Schwanau-based company Herrenknecht are being used. "Tunnel construction in the Alps and especially on the St. Gotthard in Switzerland always has an emotional component for us. We are looking forward to working with the miners on the construction site," says Matthias Schwärzel, the responsible project manager, proudly. Drilling under the Gotthard massif is hard work in the truest sense of the word: “The machines work under extreme conditions and have to contend with dust and heat as well as the hard rock,” explains Rothe-Erde Sales Manager Stefan Sünning. “The slewing bearings used must of course be of a correspondingly high quality and resilient, especially as they work in continuous operation during tunnelling.” Three-row roller bearings with a diameter of over six and a half meters are used, which are characterized by their robustness, durability and, last but not least, low maintenance: "There are enough imponderables in tunnel driving in a project like this. That's why we and our bearing have to be a consistent factor," says Stefan Sünning. He is certain: "We have been working very successfully with Herrenknecht on tunnel construction projects all over the world for more than 40 years. I am sure that we will be driving through the new tube in 2033."

First tube will be renovated by 2033

Once the boring work has been completed, it will take another three years for the second tube to be commissioned. This time will be needed to install the operating and safety equipment and for various test runs. The parallel first tube will then be closed for renovation work for a further three years until 2033.