Lilia and Ida breakthrough on Brenner Base Tunnel: delivery and design notes for engineers
Reviewed by Joe Ashwell

First reported on Tunnelling Journal – News
30 Second Briefing
Breakthrough of Herrenknecht Single Shield TBMs “Lilia” and “Ida” in Brenner Base Tunnel section H41 Sill Gorge–Pfons marks completion of two 10.25 m diameter, 4,550 kW drives totalling over 16.5 km of twin main tunnels excavated and segmentally lined since mid‑2023. The 2,400‑tonne, 160 m long machines, operated by ARGE H41 (Implenia, Webuild, CSC), bring Herrenknecht’s driven length under the Brenner towards 90 km, with two 10.33 m Double Shield TBMs still advancing on lot H53. Herrenknecht is also supplying segment formwork systems, VMT navigation and ring sequencing, and multi‑kilometre H+E conveyor belts, consolidating a full-process mechanised delivery model.
Technical Brief
- All advance has been segmentally lined with precast concrete, implying immediate ring build and minimal exposed face length.
- Herrenknecht’s scope includes Herrenknecht Formwork for segment production, integrating TBM ring geometry with casting operations.
- VMT GmbH navigation and ring sequencing systems manage guidance and ring build order over multi‑kilometre drives.
- H+E GmbH conveyor belts, several kilometres long, provide continuous muck haulage, reducing reliance on diesel truck logistics.
Our Take
Implenia’s role on both the Brenner Base Tunnel and Norway’s Sandbukta–Moss–Såstad double-track (via the MossIA JV in our related coverage) signals that its underground and rail portfolio is now spread across key north–south European freight and passenger corridors, which may help it leverage lessons learned on logistics and risk allocation between alpine and Nordic ground conditions.
With eight Herrenknecht TBMs deployed on Brenner and a further six ordered by TELT for the 70 km Mont Cenis Base Tunnel, Herrenknecht is effectively embedded across the two flagship Alpine base tunnels, which likely gives it strong influence over standardisation of lining systems, guidance tech (via VMT), and maintenance regimes for long transalpine rail drives.
The combination of large-diameter (around 10 m) Single and Double Shield TBMs on Brenner, plus similar-scale machines on Mont Cenis, suggests that contractors such as Webuild and Implenia are consolidating around mechanised excavation for long European base tunnels, reducing reliance on drill-and-blast and potentially tightening the market for high-capacity TBM crews and specialised support suppliers in the Alps region.
Prepared by collating external sources, AI-assisted tools, and Geomechanics.io’s proprietary mining database, then reviewed for technical accuracy & edited by our geotechnical team.
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