U2 x U5 Metro Lines

All photos ©ARGE Linienkreuz U2xu5

The expansion of metro lines U2 and U5 is currently one of Vienna’s largest infrastructure projects. Construction has been in full swing since early 2021 and, after six years of work, is expected to deliver capacity for 300 million additional passengers and create 30,000 new jobs for the two-million-strong capital—while saving around 75,000 tonnes of CO₂. What it takes to achieve this below ground is explained firsthand by SWIETELSKY metro specialist Wolfgang Friedl.

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A public-transit fan—professionally and personally

“I’m a huge fan of Vienna’s public transport,” says SWIETELSKY division manager Wolfgang Friedl as we meet at the site office of the U2xU5 joint venture at Rathaus/Frankhplatz. Right outside—largely out of sight beneath Auerspergstraße—one of the key sections of the metro expansion is taking shape: more than two kilometres of tunnels and numerous shaft structures. For Friedl, it’s personal too: he commutes every day by suburban rail from Purkersdorf and covers the last stretch in a climate-friendly way by bike.

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Building in the city’s protected historic core

With a budget of around €242 million, the project is considered one of Vienna’s largest climate-protection initiatives—and it also comes with the highest demands, because major historic landmarks line the route, including City Hall, the University, and Otto Wagner’s famous “Hosenträgerhaus.” Beyond the much-publicised relocation of a plane tree near Café Eiles, many crucial protective measures happen out of public view: foundations have been reinforced, buildings structurally upgraded, and concealed drainage wells drilled in courtyards and basements to safeguard the historic fabric.

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A tough start—and engineering on a massive scale

Work began under challenging conditions: the contract came in December 2020, and construction started in January 2021—amid heavy snowfall and in the middle of a major COVID wave. The engineering scale is enormous: shaft support includes bored piles up to 60 metres long. On earlier U5 works, SWIETELSKY also used modular hydraulic struts spanning shaft widths of up to 32 metres—a reusable solution with advantages in schedule and structural safety.

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Around-the-clock effort—and clear benefits for Vienna

More than 40 staff members and over 200 workers are involved on site, with tunnel excavation operating almost around the clock. The goal is to complete the U5 to Frankhplatz by 2026, followed two years later by the U2 to Matzleinsdorfer Platz. This will add capacity for around 300 million additional passengers and significantly ease environmental pressure: shifting traffic from cars to public transport can save up to 75,000 tonnes of CO₂ per year.