Brenner Base Tunnel

Isarco River Underpass section

High Speed Railways

Start of works

October 2014

Progress status


Data updated to November 2021

Brennero, Italy
SDG Obiettivi di sviluppo sostenibile
Climate action Climate action
Industry innovation and infrastructure Industry innovation and infrastructure

The southern end of the railway that connects Munich to Verona

The Brenner Base Tunnel is at the heart of the new Brenner railway link from Munich to Verona. Once completed, it will be, at 64 kilometres long, the longest underground railway connection in the world.

The Isarco Underpass lot is the southernmost part of the Brenner Base Tunnel before entering the Fortezza station. It is located one kilometer north of the town of Fortezza, in Prà di Sopra, in the province of Bolzano.

The section will include civil works for the two main tunnels for a total length of roughly 4.5 km, as well as two interconnecting tunnels for a total length of 1.7 km that connect with the existing railway line.​

Technical data

East inteconnection (m)


West inteconnection (m)


Connection tunnels' total length (m)


Supply chain: 918 companies from all over Italy involved in the Isarco River Underpass Section

Nearly 1,000 businesses at work with Webuild longest underground railway connection in the world.


Sustainable KPIs

Reduction of travel times


Passenger expected per year


C02 emissions avoided per year

2,800 t


A safe underpass due to liquid nitrogen

Construction will be extremely complex from a technical point of view: both the main tunnels and the interconnecting tunnels will pass under the Isarco River, the A22 motorway, the SS12 motorway and the Verona-Brenner railway line with minimal leeway.

Webuild has started using a special application to allow workers to excavate a tunnel under the Isarco River safely and sustainably without having to divert the natural course of the river.

The Group is overseeing the use of liquid nitrogen to freeze the ground along the tunnels being excavated for the underpass: by freezing the ground, workers can proceed with the excavation of the tunnels without being hindered by water infiltration.


Brenner Base Tunnel

Webuild Project

Brenner Base Tunnel

Isarco river uderpass - freezing operations