Power problems and a stuck train interrupted rail services through the undersea Channel Tunnel connecting the United Kingdom and continental Europe on Tuesday, operators said, stranding passengers during the busy end-of-year holidays.

At Paris’ Gare du Nord station, Jamie and Issy Gill scrambled to find a flight back to the U.K. after their Eurostar train to London was canceled, desperate to be reunited with their baby boy after a getaway in the French capital.

“We came for my 30th birthday,” Issy Gill said, wiping away tears.

Jamie Gill said they’d take a roundabout route back, with a flight via Birmingham on Wednesday.

Eurostar — which runs passenger trains between London and Paris and other European destinations — blamed “overhead power supply issues in the Channel Tunnel” and a failure aboard a train operated by LeShuttle, which transports vehicles and their passengers between the ports of Calais, France, and Folkestone, England.

On Tuesday afternoon, Eurostar said the tunnel was partially reopening but with only one of its two train lines, allowing Eurostar services to resume in the evening — although with expected continued delays and longer journey times than usual. It advised passengers to rebook their journeys on other days.

The 50-kilometer (32-mile) Channel Tunnel, more than half of it undersea, has revolutionized U.K.-Europe rail travel since its inauguration in 1994. But because it’s the only fixed cross-English Channel rail link, train services tend to be vulnerable to severe disruptions.

The Gare du Nord station heaved with frustrated passengers trying to book plane or bus tickets.

“I’m disgusted, disheartened,” said Sarah Omouri, a French traveler whose plans to celebrate the New Year in London were dashed.

“It’s been maybe a year since we’ve had a vacation,” she said. “We were made to get on the train, to get off, get on again, and get off again. Now we’re told that everything is fully booked for several days. It’s ruined.”

In London, would-be traveler John Paul had expected to enjoy a romantic river cruise in Paris and a trip to the Eiffel Tower with his partner, Lucy, but their Eurostar got turned back before reaching the continent.

“We got probably about an hour down the track, maybe 40 minutes, and then they basically said the train’s got to stop, because the train ahead got a braking issue,” the 46-year-old Paul said.

“They kept telling us that the driver was trying to fix the brakes on this other train and that the other trains were then backed up,” he said. “There’s no clear information and, obviously, we’ve lost a lot of money, haven’t we?”