A signalling problem which left passengers stranded for several hours between south Wales and London has been fixed.
Trains were suspended while repairs were carried out on a broken signal between Swindon and Didcot Parkway.
National Rail Enquiries said lines had reopened but disruption would continue.
Passengers on the 13:33 BST service from London Paddington to Cardiff Central were among those affected.
Earlier, one passenger said they had been waiting on the train near Swindon for hours before being returned to Didcot station.
"All they have done is bring us back to the station to stretch our legs, what we are doing, how we are getting home, no one seems to know," she said.
"I should have been back home by 15:30. All we have been offered is a cup of tea."
Services were affected between Swansea, Bristol Temple Meads, Penzance and London Paddington.
In an update at 21:15 BST, National Rail Enquiries said a limited service was able to run but "disruption will continue until the end of service".