There's disruption on the First Great Western line between Cardiff and London Paddington.
It means no trains are running between Bristol Temple Meads and London Paddington; Cheltenham Spa and London Paddington; and Oxford and London Paddington. It's due to signalling problem between Didcot Parkway and Swindon.
Tickets being accepted on CrossCountry and Virgin Trains services.
More top news
A 42-year-old man who staged a bomb hoax resulting in hundreds of homes being evacuated in Fishponds has been jailed for 20 months.
Laurence Llewelyn-Bowen pledges to fix The Magical Journey Christmas experience he designed, which shut down after a string of complaints.
Gavin Henson booted an 18-point haul as Bath moved up to second in the Premiership with a 33-23 win over struggling London Irish.