LONDON — Eurostar passengers are braced for a second day of possible disruption, after a power outage in the Channel Tunnel caused travel chaos for thousands of people on Tuesday.

Some travellers spent hours stuck onboard trains overnight as they waited for them to move.

Train services through the Channel Tunnel linking Britain and continental Europe were suspended for much of Tuesday after a power supply failure, bringing chaos to peak winter holiday travel.

The disruption, caused by a fault in the overhead power supply, upended plans for thousands of passengers in London, Paris, Brussels and Amsterdam during one of the busiest travel weeks of the year.

In a statement on its website at 1530 GMT, high-speed train operator Eurostar said that the 31-mile-long (50-km) tunnel was partially reopened and that services were resuming gradually. But it warned passengers that the power fault was persisting.

Some Eurostar passengers have been sharing their experiences after being stranded after power problems and a stuck train interrupted rail services through the Channel Tunnel on Tuesday, ruining the New Year holiday vacation plans during the busy end-of-year holiday period.

At Paris' Gare du Nord station, Jamie and Issy Gill scrambled to find a flight back to the UK after their Eurostar train to London was cancelled, desperate to be reunited with their baby boy after enjoying a getaway together in the French capital.

One man told the BBC he had boarded the 19:01 service to Paris, but as of 02:30 GMT he was still stuck on the train at the entrance to the tunnel.

He said staff told him there was a "50% chance we go to Paris, 50% chance we go back to London".

Some Eurostar and LeShuttle services resumed on Tuesday evening after one of the tunnel's two lines reopened, but delays continued.

Getlink, who run the Channel Tunnel, said work is continuing through the night to fix the power issue.

It said it hopes it will return to normal overnight.

Earlier on Tuesday, Eurostar urged its customers "to rebook their journey for another day if possible, with free exchanges available".

"We also advise customers not to come to our stations if their trains have been already been cancelled."

By midday on Tuesday, at least a dozen Eurostar services between the UK, France, Belgium and the Netherlands had been cancelled.

The rail operator apologised and said passengers could rearrange their plans free of charge or can cancel their booking and get a refund or an e-voucher.

Passengers told the BBC how they had been left stranded and looking for alternative routes to get to their destination.

Two American tourists spent hundreds of pounds to reach Paris on Wednesday after their Eurostar service was cancelled from London St Pancras International.

Haley Adams, 38, and Hannah Hagar, 35, paid $580 (£430) for flights to the French capital to celebrate Hannah's 36th birthday there.

The pair had their Eurostar tickets refunded but said they will have to pay for an extra night at a hotel in London and cannot get a refund from the hotel they were going to stay at in Paris tonight.

"There's been a lot of queuing," Adams said. "We have been here for five hours."

A family from Mexico said their trip of a lifetime has been cast into doubt as their Eurostar service was cancelled.

Monserrat Hernandes, her brother John Paul and mother Olga were among dozens of people looking frantically at their phones near the Eurostar departure area at St Pancras.

The family got on the Eurostar just after 08:00 GMT but after their train left for Paris it had to return due to the incident.

In France, Ben Clark, from Bedfordshire, said he had been stuck on-board Le Shuttle in Calais with his wife and three daughters for hours.

"The first two-and-a-half hours weren't too bad but the girls have got restless in the last half an hour so we've let them run around the boarding carriage to burn off some energy," he said.

National Rail has advised passengers not to come to London St Pancras International if their Eurostar train is cancelled, while the Department for Transport said disruption is "likely for the remainder of the day" while faulty overhead cables are repaired.

A photograph shared with the BBC by a train driver for Eurostar appears to show overhead electrical cables strewn across the tracks.

Currently only one of two main tunnels in the Channel Tunnel is available for trains to run on, Eurostar said.

Eurostar's services resumed with the 15:04 train from London to Brussels departing after 16:00.

As of 18:00, only a few services to Paris Gare du Nord and Brussels were scheduled to depart London St Pancras International this evening.

The broken down LeShuttle train was also moved out of the Channel Tunnel. The operator said none of its passengers were stranded inside the tunnel after the power failure caused its closure.

LeShuttle has apologised and warned of delays of approximately five hours, telling passengers to "please check in as planned".

The LeShuttle service "resumed very gradually on one track" shortly before 15:00 local time (14:00 GMT), the EuroTunnel Press Office said.

"Service is operating alternately in both directions with significant delays," it said, adding that "additional shuttles will be added in the evening and until tomorrow morning".

Traffic has also eased on the M20 after cars hoping to cross the Channel Tunnel caused traffic jams near the LeShuttle Terminal in Folkestone.

Eurostar’s ambitious plans to launch a series of direct rail connections between Germany and the UK are one step closer to becoming a reality.

Earlier this year, the high-speed rail operator announced it would expand its network to introduce new routes connecting London to key European destinations such as Frankfurt and Geneva.

Following increased demand for international rail travel, Eurostar said it will also invest around €2 billion in up to 50 new trains to accommodate the expansion. — Agencies