Pilot: Renewal of SBB underpasses with UHPC ballast troughs

The 10 underpasses were already in operation when the line opened in 1897. For the redevelopment of the natural stone arch bridges, ballast troughs made of ultra-high-performance fiber-reinforced concrete were used for the first time on the SBB rail network. The troughs do not need to be additionally sealed and are extremely slender with a thickness of 5 centimetres. This improves the material balance and eliminates the need for track lifting. The redevelopment also included the repair of the historic natural stone masonry.

The new ballast troughs were used in nine underpasses. In one underpasses, the clearance profile was to be enlarged, which is why the arched masonry was replaced with a new reinforced concrete frame.

Nine underpasses were renovated in an intensive construction phase with 10 days of total closure, while one underpass underwent a further intensive construction phase with a weekend closure.