The flooding of the Wien River, following severe weather and storms in mid-September, has caused significant damage to an U-Bahn construction site at Pilgramgasse, Vienna’s transit authority Wiener Linien has said.

The full financial and scheduling impacts are still being assessed.

The floodwaters, which rushed through the Wien River, were described as a 1-in-1,000-year event. Despite protective measures, the construction shaft at the future U-Bahn interchange – where the new U2 line will eventually connect with the U4 – filled with 19,000 cubic metres of water, equivalent to the volume of about 50 large family homes. In some areas, the water rose as high as 10 metres.

According to Managing Director Gudrun Senk, it’s unclear whether the project’s completion date will be delayed further.

An initial assessment revealed that construction machinery and vehicles were completely destroyed by the flooding. Equipment such as drills and diggers were fully submerged and are now unusable due to severe damage to the electronics and engines.

Some of the vehicles, weighing up to 50 tonnes, had to be dismantled and lifted out of the construction pit by crane, according to Senk. Efforts are currently underway with contractors to source replacement machinery, aiming to restart work on the U2 project as soon as possible.

The riverbed of the Wien River in this area also sustained damage. Wiener Linien reported that they are working with the construction companies and the Vienna Water Department (MA 45) to promptly find a solution for repairs.

Concrete slabs in the riverbed were torn away, and sections of soil were eroded, Senk explained. This will need to be repaired before any further digging can take place.

Senk described the situation as causing “a significant delay.” Whether the overall project completion will be postponed again is still uncertain. Only this summer, it was announced that the U2 extension would not open by the end of 2028 as planned, but had been delayed until 2030 due to technical issues.

The financial impact is also yet to be determined, though Senk noted, “We’re talking about damage in the millions.” It’s now a question of whether insurance or disaster relief funds will cover some of the costs.