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Semmering Base Tunnel

Written by Roma Publications

Semmering Base Tunnel

The Semmering Base Tunnel is designed to reduce gradients and increase the line speed on the Vienna – Bruck an der Mur main line, so that when it opens in 2026 the Vienna – Graz journey time will be cut by 35min to 2 hours.

The project entails the construction of 62km of running tunnels, plus 8km of access tunnels, as well as connecting tunnels and shafts.

As of right now, adding up all the work that has been completed thus far, including the access tunnels, already constructed are more than a quarter of all the cavities in the Semmering Base Tunnel. Four tunnel construction sites are being set up for logistical and time reasons. Work was also started at the western portal construction site this year, starting in Mürzzuschlag.

Lower Austria

The Lower Austrian contract section; the Gloggnitz tunnel, will be classically built from two construction sites using excavators and blasting. This tunnel runs from the tunnel portal in Gloggnitz and is being built in the direction of Mürzzuschlag. Currently, this track is 3.5 kilometres long and runs through the mountain from Gloggnitz using both tunnel tubes. The tubes are connected every 500 metres with cross-tubes ( seven of them have already been built). An inner shell has even already been installed in two of the cross-tubes, which stabilises the tunnel in the long term.

From the Göstritz (Schottwien/NÖ) entrance, the miners are building towards Gloggnitz and Mürzzuschlag. There, the 1-kilometre long access tunnel has been completed and the two 250-metre-deep shafts have almost been built.


The contract section, the Fröschnitzgraben tunnel, forms the middle section of the Semmering Base Tunnel. From here, construction is underway in the direction of Gloggnitz and Mürzzuschlag. The approximately 4 km section towards Mürzzuschlag will be created using excavators and blasting, and the approximately 9 km section towards Gloggnitz will be built using two tunnel boring machines. In order for tunnel construction from Fröschnitzgraben to commence, two shafts had to be built deep inside the mountain.  The first of the two tunnel boring machines at the Semmering Base Tunnel, which has been nicknamed “Carl”, started work in summer 2018 in the northern tunnel tube and has already dug more than 2 kilometres in the direction of Gloggnitz. The second machine, called “Ghega”, has been excavating the southern tunnel tube, which runs parallel to the northern one, since May 2019.

The miners first worked their way deep down 100 m shafts in the contract section, the Grautschenhof tunnel, between Spital am Semmering and Mürzzuschlag. Currently, the two tunnel tubes are being excavated using excavators and blastings both in the direction of Mürzzuschlag and Gloggnitz; currently, around 1 kilometre of tunnelling has been completed in all four tunnels.

Mürzzuschlag Portal Area and Context Projects

As part of the construction of the Semmering Base Tunnel, the Mürzzuschlag railway station will also be rebuilt to meet the requirements of a modern traffic junction. With its new forecourt, the station will be more modern, customer-friendly and barrier-free. The bus station will also be rebuilt closer to the station building, shortening the walking distances for future rail customers. As ÖBB-Infrastruktur expects there to be significantly more rail customers at Mürzzuschlag station after the Southern Line has been completed, the existing Park&Ride facility will be expanded to 370 parking spaces. During the course of the conversion work, a modern maintenance base with a rail track hall, location for rescue trains and service buildings will also be built. Rebuilding work will be carried out on the station itself while the railway line continues to operate here.

The tracks in the area around the station must be adapted so that the Semmering Base Tunnel is integrated into the existing line. As the area around the Mürzzuschlag railway station is part of the Semmering Railway Unesco World Heritage zone, all work must be coordinated with a Design Advisory Board and the National Heritage Agency (Bundesdenkmalamt).


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