Tauern Railway Tunnel

The Tauern Railway Tunnel is showing its age. It is time for a comprehensive modernization of one of the main rail corridors crossing the Alps. We at SWIETELSKY are taking on the challenge, overcoming a tunnel collapse and other surprises deep inside the mountain while carrying out the renovation partly with new technologies that have never been used before. Always with one goal in mind: delivering high quality and meeting an ambitious schedule.

Tunnel construction without tunnel vision

The historic structure of the Tauern Tunnel consists of granite blocks that were laid by hand 117 years ago. Removing the damaged stones must therefore be done very carefully – using four specially built prototype machines developed for this purpose.

“With these multi-blade saws, we can make lamella cuts up to 30 cm deep. This allows us to carefully remove the damaged sections using hydraulic excavators and milling attachments without significantly weakening the masonry structure. This technology is new – we are pioneers in this field,” says Wolfgang Pacher, Managing Director of SWIETELSKY Tunnelbau.

In addition, SWIETELSKY teams are carrying out numerous injection works in the Böckstein area to improve the bedding of the tunnel lining and seal the masonry.

Track construction with obstacles

A total of 8 kilometers of railway line – equivalent to 16 km of track – must be renovated. On 4 km, the slab track must be completely renewed, meaning the old concrete is removed and replaced. In addition, the foundation beneath the slab track is no longer usable and must also be replaced.

On another 12 km, all rail support points must be replaced. It sounds straightforward, but it is anything but simple. These support points secure the rails to the concrete – each one weighing about 10 kg, adding up to 420 tonnes of material. Much of it has corroded and is extremely difficult to remove.

“All of this is a premiere – a railway tunnel track has never been renewed on this scale before,” explains Rainer Marx, Project Manager for Railway Construction. A true challenge for all SWIETELSKY teams working deep inside the mountain.

Challenges underground

Even before the project began, bringing all the necessary equipment and sufficient personnel to the site was a major task.

“This is where the experience of our people and the size of SWIETELSKY really pay off – we can offer the client everything from a single source,” says Wolfgang Pacher.

Despite the difficult conditions inside the mountain, the work is progressing quickly. Up to 330 SWIETELSKY employees are working in the tunnel 24 hours a day, seven days a week.

Surprises are part of daily life on site – not surprising for a tunnel that has been in operation for so many years. For example, last December a larger tunnel collapse occurred at the north portal. Fortunately, no one was injured and all 13 colleagues were able to reach safety in time, reports Wolfgang Pacher.