Disruption on Great Western Railway (GWR) services brought about by the discovery of cracks in some trains could continue for days, the Rail Delivery Group has said.
The operator's Hitachi 800 trains were pulled from lines across the West Country yesterday (May 8) after cracks were found in some trains.
GWR is continuing to advise people not to travel today (May 9) and that refunds will be provided, as there will be no trains or an 'extremely limited service.'
Local services are running but they are expected to be very busy and rail replacement services will be extremely limited.
London Paddington - Swindon - Bath Spa - Bristol Temple Meads.London Paddington - Swindon - Bristol Parkway - Newport - Cardiff Central - Swansea.London Paddington - Reading - Taunton - Exeter St Davids - Plymouth - Penzance.London Paddington - Reading - Swindon - Gloucester - Cheltenham Spa.
Other rail firms not affected by the faults, including Avanti West Coast and West Midlands Railway, are taking GWR passengers on ‘any reasonable’ route.
Robert Nisbet, regional director at the Rail Delivery Group, told BBC Breakfast: "With the inspections completed initially by the end of today, we are still expecting some disruption to carry on for a few days.
"It's impossible for me to say how long that is going to take, but we are obviously going through this as quickly as possible, but we don't want to rush it.
"We want to ensure that all of those trains are thoroughly inspected and cleared and put into service when things are ready, but there may well be a knock-on effect for some of those timetables into next week.
"It's fair to say this didn't pose any particular danger to passengers that were travelling on those trains but if you don't treat these kind of issues early on they have the potential to develop."
Hitachi Rail has apologised after cracks were found during routine checks yesterday, adding that by Saturday evening "some trains" had been cleared to run as normal.
Rail minister Chris Heaton-Harris has asked operators to deploy extra staff to help passengers complete their journeys and access refunds.
He added: "I share the frustration of passengers who are experiencing significant disruption and would ask people whose journeys are affected to check before travelling."