TECHNICAL | LININGS
OPTIMISED LINING FOR GRIPPER TUNNELLING
MONT CENIS -
Below: Two Herrenknecht Gripper TBMs (Ø 10.43m) for Lot CO5 of the Mont Cenis Base Tunnel PHOTO CREDIT: HERRENKNECHT
Construction activities on the base tunnel of the Lyon-Turin (TELT) high-speed rail project will include use of Herrenknecht’s ‘Wurm’ lining and installation system behind the Gripper TBMs. Use of Wurm on the project is outlined by Frédéric Battistoni, Head of Project Management, Traffic Tunnelling, Herrenknecht, and Roland Herr, Freelance Journalist
The world’s longest railway tunnel is currently being built in the Alps between Lyon, in France, and Turin, in Italy. The two parallel, 57.5km-long tunnels under Mont Cenis form the centrepiece of this new rail link. For the excavation of the base tunnel, the contracting joint ventures have ordered a number of Herrenknecht tunnel boring machines, including two 334m-long Gripper TBMs with two 650m-long lining and installation systems – the so-called ‘Wurm’. They are intended to support the tunnellers in completing the lining of the bored tunnels within the specified time frame.
1 - PROJECT OVERVIEW The new 164km-long railway link between Lyon and Turin closes a gap in European infrastructure in terms of the rail network. It will form part of the Mediterranean Corridor within the EU’s Trans-European Transport Network (TEN-T). The centrepiece of the new line will be the 57.5km-long base tunnel under Mont Cenis, with the French-Italian TELT (Tunnel Euralpin Lyon Turin) responsible for the project. Mont Cenis Base Tunnel is a complex system
consisting of two parallel main tubes, four access tunnels and 204 safety bypasses. At the peak of tunnelling on the project, a total of seven TBMs will be in operation simultaneously. The joint ventures contracted by TELT have ordered a number of machines from Herrenknecht AG. One TBM has commenced tunnelling and four have been formally accepted at the plant. The first of the two TBMs for excavating the tunnel section on Italian soil has been ordered and is ready for acceptance in March 2026. In Lot CO6/7 (Chantiers Opérationnels) ‘Saint
Martin-LaPorte – Villarodin-Bourget/Modane’, three single shield TBMs with a diameter of 10.34m are each carrying out 8.3km of hard rock tunnelling with segmental lining. For the neighboring Lot CO5 ‘Villarodin-Bourget/
Modane – Chiomonte’, two Gripper TBMs with a diameter of 10.43m and two Wurm installations are being used to construct the 18km-long tunnels. A multi-
24 | March 2026
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