ROCK TUNNELS | PROJECT


Brenner Base Tunnel and Connecting Tunnel


Right:


Map of Brenner Base Tunnel and Connecting Tunnel, showing advanced status of construction activities


Ahrental Access Tunnel Wolf Access Tunnel Constructed (end of Sep 2025) Mules/Mauls Access Tunnel


Ampass Access Tunnel


Long sought after, the enhanced Brenner link is


set to be completed in the near future. High-speed rail services are planned to start running through the long Alpine base tunnel in the early 2030s.


PROJECT - CONTRACT ORGANISATION The tunnelling packages on the full Brenner project are organised in the following Lots, in sequence from north to south along the alignment (Austria to Italy):


For the TEN-T route link tunnel: ● H33 - Tulfes to Pfons


And, for the Brenner Base Tunnel: ● H21 - Sill Gorge ● H41 - Sill Gorge to Pfons ● H53 - Pfons to Brenner ● H52 - Hochstegen ● H61 - Mules 2-3 ● H71 - Isarco River underpass


In Austria, a long connecting tunnel (Lot H33) allows the TEN-T high-speed route to join the Brenner Base Tunnel while bypassing the northern portal, at Innsbruck. The tunnels are not aligned and the connection is a relatively sharp turn. The connecting tunnel’s own portal is farther north, at Tulfes. This connecting link utilises a prior rail bypass tunnel while adding various extra tunnels plus the necessary tie-ins to the northern end of Brenner Base Tunnel. The Brenner Base Tunnel itself extends from the


Innsbruck portal southwards to Italy, to the Fortezza portal (in Italian, or Franzensfeste in German). It is far longer than the connecting tunnel and, as such, its Lots hold the majority of the underground works needed for the entire Brenner link project, including H21 to H71 as listed, plus other tunnels. Some of the Lots are near the portals, which


provided them with access for the works, but most of the excavations for Brenner Base Tunnel are along the alignment and required intermediate adits to get underground for main tunnelling activities. These access and logistics tunnels are (north to south):


Connecting Tunnel: ● Austria: Ampass Access Tunnel; part of H33


Crosscut 333m 70m


And, for the Brenner Base Tunnel: ● Austria: Ahrental Access Tunnel; ● Austria: Wolf Access Tunnel; ● Italy: Mules (Italian) or Mauls (German) Access Tunnel;


The alignment also includes construction of three large tunnels complexes as Emergency Stop, at: ● Innsbruck; ● St Jodok; ● Trens


In addition, to help prepare for all these works, the planners strategically invested in an exploratory tunnel to run the full length of the Brenner Base Tunnel. With early excavations in different sections along the alignment, the main tube and cavern works were prepared for, and the tunnel will have a future in the operational stage of Brenner Base Tunnel. The Lots, the tunnelling works involved and their


West tunnel ø8.1m


Exploratory tunnel ø6m


East tunnel ø8.1m


status - main excavations completed or works still underway - are discussed in the following sections.


24 | December 2025


Innsbruck


Innsbruck Bypass Tunnel (TEN-T Connecting Tunnel)


AUSTRIA ITALY


Fortezza/Franzensfeste Aicha/Aica


Exploratory Tunnel


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