The Inntal Tunnel, a key component of the southern Innsbruck bypass, was completed and commissioned in 1994. It was electrified and constructed as a double-track line with a ballasted superstructure. Already during the planning phase, the tunnel was designed to allow for a future connection to the Brenner Base Tunnel without the need for major structural modifications.
As installation work on the Brenner Base Tunnel approaches, the Inntal Tunnel will need to be adapted in an initial phase starting in 2028 to enable material deliveries to the Brenner Base Tunnel. During this time, a temporary construction station consisting of two sidings will be set up in the “Aldrans junction” cavern. This means that trains delivering and removing materials for equipping the Brenner Base Tunnel can be parked without disrupting ongoing rail operations in the Inntal Tunnel. At the same time, the tunnel infrastructure in the Inntal Tunnel, which has been in operation for over 30 years, will be partially renewed and the current tunnel safety level between the Tulfes portal and the Brenner Base Tunnel link will be upgraded from freight traffic to mixed traffic. Plans include widening the side paths, fitting handrails with emergency lighting and modernising the electrical and rail safety systems. In addition, the tunnel drainage systems will be renovated in sections. A newly installed long-distance flushing system will also enable flushing operations to be carried out from the rescue tunnel in future, eliminating any impact on ongoing rail traffic. The final scope of works is currently being further defined as part of the technical and economic evaluation of individual measures. This ongoing process forms part of project delivery and ensures that implementation is optimally aligned with the existing framework conditions while capturing the associated financial impacts. Installation work in the Brenner Base Tunnel is scheduled to be completed by 2031. The construction station, which will then no longer be needed, will be dismantled and the Inntal Tunnel will have the planned rail infrastructure for high-speed mixed traffic in its final state. In future, trains will be able to enter the Inntal Tunnel at Tulfes, enter the Brenner Base Tunnel via the connecting tunnels and leave it again at Franzensfeste, and vice versa. In the connecting tunnels, there is also a safe changeover from Austrian right-hand traffic to Italian left-hand traffic. Connecting the Brenner Base Tunnel to the Inntal Tunnel will create a continuous railroad infrastructure system of approx. 64 kilometres in length. This will allow international freight traffic to bypass the city of Innsbruck and use an efficient, safe and sustainable connection between Germany and Italy under the Brenner Pass.
Thomas Gstreinthaler, BERNARD Gruppe
Foto ©: BBT SE
