Up to 500 passengers were trapped on a train in the Channel tunnel for four hours after a loss of power in an overhead wire gantry.
The Eurotunnel train was just a couple of kilometres from the French side when the incident occurred at about 10am, a spokesman for the company said.
The train, which had 130 cars on-board, was later pulled out by another train. No-one was injured.
A Eurotunnel spokesman said: "It would have been a bit eerie down there and reasonably hot, but the normal safety procedure is that the best way of dealing with this is to pull the train out rather than getting people to walk along the lines." He added that a reduced service would be operating for the next few hours.
One passenger has said she was trapped for over six hours with her family on the service from Folkestone to Calais. Emma Collins told BBC Five Live that she and her three young children aged six, four and 11 months had been stuck in their car.
"We got stuck in the Chunnel for over six hours, six and a half hours," she said. Miss Collins said her children had coped well with the situation.
"They were fine, they were really well behaved. And luckily they could get out of the car and move around. But it did start getting very very hot."
She added: "It got very, very hot and three babies I understand, were taken very poorly. They had to get a doctor on board to see to them. Our thermometer was saying it was over 30, 31 degrees. It's just that there was no air circulating at all."
But the holidaymaker, who was well on the way to Brittany when she spoke to the radio station, said there had not been any sense of panic amongst the passengers and that staff had attempted to ease their discomfort by distributing water.
"Everybody was really remarkably calm, surprisingly. It was just the children, they got very, very hot. But they did hand out water on the train."
