Jessica Chambers, from Essex, was supposed to be travelling to Amsterdam for her friend’s birthday.
Speaking to the BBC while she was stuck on board, she said: “It truly feels like an emergency situation but there’s no communication from staff.”
Eurostar said on X that it was not possible to make customer announcements “due to a lack of power on board”.
At about 15:15 GMT, Ms Chambers said the train was getting dark as the lights were out due to the lack of power.
“Following a complicated situation due to the position of the train and the track infrastructure, it’s meant that certain safety procedures had to be adhered to before we could move the train,” said Eurostar.