Ready for the next 80 years

Around 500 trains pass through the eight-kilometre-long Hauenstein Base Tunnel every day. At the centre of this key artery in the Swiss rail network is a 134-metre-high ventilation shaft with a diameter of five metres. Its refurbishment requires the highest levels of precision and experience, as well as a perfectly coordinated team.

The comprehensive refurbishment of the imposing ventilation shaft forms part of a CHF 50 million contract to rehabilitate the entire Hauenstein Base Tunnel. It is also the most demanding element of the contract – due to the depth and confined working conditions, the shaft presents a particular technical and logistical challenge.

During this project, a specially constructed crane tower serves as the working platform and is assembled from the bottom upwards using a total of 30 elements. Even before the tower was erected, the entire shaft was equipped with permanent LED lighting and a stable Wi-Fi network. This infrastructure is essential for safe and efficient operations.

Working from the platform, the employees use a demolition robot to progress gradually downwards. Among other tasks, they remove extensive limescale deposits that have accumulated over approximately 100 years. At the same time as the demolition work, a waterproofing membrane is installed over the entire height of the shaft.

Working around the clock, an inner concrete lining is installed using slipform construction. Around 45 cubic metres of concrete are placed in the shaft each day in a controlled and uniform manner. This demanding interplay of technology, experience and teamwork will ensure that, once the work has been completed, the ventilation shaft remains safe and operational for another 80 years.