Eurostar services to and from Brussels were severely disrupted on Wednesday following a problem with the overhead power supply near Halle.
The rail operator was forced to cancel six Brussels services and one train broke down for two hours between Halle and Tubeke with around 600 passengers on board.
Some passengers took to twitter to complain about the lack of air conditioning in the 40 °C heat.
Staff were said to be handing out water to those trapped on board before all passengers were finally evacuated.
Eurostar sent an empty train to take passengers back to Brussels.
The following trains were then cancelled on Wednesday:
ES 9132 (12:58 from London to Lille/Brussels)
ES 9141 (14:56 from Brussels/Lille to London)
ES 9145 (13:46 from Amsterdam to Brussels)
ES 9149 (16:56 from Brussels/Lille to London)
ES 9152 (18:04 from London to Lille/Brussels)
ES 9157 (18:56 from Brussels/Lille to London)
Passengers due to travel on one of these trains can exchange their ticket for free or request a refund for the value of their ticket.
"We apologise for the inconvenience and we thank you for your patience," said Eurostar.
