Symbolic Groundbreaking Ceremony at the North Portal of the Brenner Base Tunnel
At the base of the Viller Berg mountain in the heart of Innsbruck's Sill Gorge, the symbolic start of tunnelling was celebrated on 28 October 2021. The significance of this important step towards connecting the Brenner Base Tunnel to Innsbruck's main railway station was underlined by the participation of Tyrol's Deputy Governor Josef Geisler, the Mayor of Innsbruck Georg Willi, as well as the two board members of BBT SE Martin Gradnitzer and Gilberto Cardola.
The western main tunnel tube heading south was begun. Prior to this, a blessing ceremony was held at the site where the future north portal of the Brenner Base Tunnel will be built. Starting from the Sillschlucht construction lot, two 140-metre-long tunnels are to be excavated in a southward direction.
Northern and Southern Portal of the BBT
The start of excavation works at this spot is especially symbolic: the future northern portal here will be a visible entry and exit point, to and from the longest underground railway connection in the world. The breakthrough of the southern portal to the Brenner Base Tunnel near Fortezza already took place in December 2018.
Whereas there (once the BBT is operational) freight trains will transit as well, the northern portal will mainly be used by passenger trains, because freight trains can use the Innsbruck by-pass. After passing through the portals in Tyrol and Alto Adige, railway traffic between Innsbruck and Fortezza will run through the two single-track tubes of the BBT for 55 km.
Since the trains coming from Brenner run on the left, at a three-track entrance towards Innsbruck Central Station a switch occurs and trains are re-routed from left to right, so that passengers can get out at the platform as usual.
A Collection of Several Structural Elements
The main portal of the Brenner Base Tunnel, along with two new railway bridges and with the portal towards Innsbruck connecting to the Silltal tunnel at the foot of the Bergisel mountain, forms a collection of structural elements.
Everything was implemented with an eye to uniformity. The portals are designed so as to be inclined to the slope, and the approx. 50-m long and 9-m high steel trellis bridges span the Sill between them.
To ensure separate ventilation for both tunnel tubes, the western steel trellis bridge will be built in a closed configuration. A panoramic viewing area above the portal of the first tunnel at Bergisel constitutes a transition from the redesigned front part of the Sill Gorge with the existing and new transport infrastructures to the natural brook gorge in the rear part of the area.
Connection to the Central Station
BBT SE, in close cooperation with ÖBB Infra, had already completed the construction lot at Innsbruck Station in September 2019. A three-track entrance to adapt the southern end of the main station to the future configuration with the Brenner Base Tunnel was built and handed over to ÖBB.The works were carried out without interrupting railway operations. The new infrastructure is already being used during the construction phase of the BBT to supply parts for tunnel outfitting.
