OBB working on the Koralm tunnel i

ÖBB nears the finish line on major Koralm tunnel project

120-metre-long pieces of rail will bolted to the support slabs. 2023, ÖBB / Chris Zenz

ÖBB installed the final concrete track support slab in Austria’s new Koralm tunnel this week, hitting a fresh milestone in a project that is scheduled to open for traffic by the end of 2025. The tunnel will reduce travel time between the cities of Graz and Klagenfurt to 45 minutes.

The 33-kilometre-long Koralm tunnel is now fitted with 13,000 concrete track support slabs, each measuring 5 metres in length and weighing in at over 5 tonnes. The units form the basis for 120-metre sections of rail, which are also currently being installed. That phase of the project is nearing completion too.

In tandem to installing tracks, ÖBB is also working on installing technical and safety systems, taking noise and vibration protection measures, as well as fitting signalling and electronic interlockings. The final piece of the puzzle will be running the the overhead conductor rail through the entirety of the tunnel.

Digital tunnel twin

Even though the tunnel has yet to be completed, ÖBB has already gained experience with future maintenance via the digital twin of the Koralm tunnel. The structure was planned and implemented using Building Information Modeling (BIM). The digital twin will also in the future be instrumental in assessing the required quantities of building materials and pieces of infrastructure along the Koralm railway, the company says.

The Koralm tunnel is the key piece of infrastructure of the Koralm railway, a 130-kilometre-long new route that features various sections, 47 kilometres of tunnels and 100 bridges. Once completed, trains on the line will call at 23 stops along the route between Graz and Klagenfurt, Austrian state capitals of Styria and Carinthia, respectively.

ÖBB/Chris Zenz
The support slabs are installed using this machine, which has its own set of tracks. Image: ÖBB / Chris Zenz

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Author: Nick Augusteijn

Chief Editor, RailTech.com

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