The Kalte Rinne viaduct of the Semmering railway in Breitenstein, Lower Austria (Image: Wikipedia)
The line’s fourteen tunnels are 1,477 metres long in total, nearly one-tenth of the route, and its sixteen major viaducts also add up to 1,477 metres. There are 118 smaller arched stone bridges and eleven iron bridges. Fifty-seven two-storey attendants’ houses stand at roughly 700-metre intervals, a characteristic feature of the line. About two and a half months of work, chiefly to renovate the Kalte Rinne viaduct, ended on 29 May 2026, when normal traffic resumed, according to Austrian Federal Railways. Crews renewed the reinforcement with around 92 tonnes of steel, laid roughly 1,200 square metres of waterproofing, and renewed 200 metres of track; the company is investing about twenty million euros this year. Trains kept running on one track from 14 March to 28 May. The operator says the mountain line will stay vital until the Semmering Base Tunnel opens at the end of 2029.
The continued operation of the line testifies to the engineering genius of project engineer Carl von Ghega, according to the World Heritage Centre. Most tunnel portals are simple but monumental, with varied ornamentation, and the support structures are largely stone, with brick used for the viaduct arches and tunnel linings. Keeping a line this old running takes constant work.
