South West rail problems could last five days
A flooded railway line in the South West could be closed for up to five days, Network Rail has admitted.
The line between Tiverton and Exeter is blocked and only limited bus replacements are available.
Engineers used plastic dams in a bid to stop water getting into signal boxes at Cowley Bridge, Devon.
But Network Rail engineer Steve Hawkins said they would have to wait for flooding to subside before they can begin repairs.
Water from the swollen River Exe has washed away the ground from underneath some of the nearby track, buckling rails and making the area unstable.
Trains between London Paddington and Penzance use the area and passengers were being advised to make alternative arrangements.
Mr Hawkins said: "Once we're assured from the Environment Agency and the Met Office that the flooding isn't going to occur again, we'll then remove the dams that we've got in place.
"We'll then start work on the structure of the track which, depending on how bad it is, it could take from between three days and five days to fix."
Mr Hawkins added flood defences installed a decade ago had worked until this winter - and the firm was now expecting more rain.
Problems at the Cowley Bridge junction mean trains are unable to run between Tiverton and Exeter.
"It happened 12 years ago, but in the past four weeks its happened three times.
"We did put protection in 12 years ago and it's done us proud up until now. But we are looking at other flood defences now.
"We do apologise to our customers at this most important time but the weather has affected us."
On Saturday, long queues built up at Taunton station as passengers tried to board bus services.
South West Trains said it would accept tickets from First Great Western passengers travelling to Devon and Cornwall.
First said the routes between Par and Newquay, Liskeard and Looe and also Exeter and Barnstaple were also facing significant problems.
All three routes were blocked by flooding on Sunday morning.
There also also problems at Badminton near Bristol, at the Severn Tunnel and the Yate to Cam and Dursley line.
Earlier problems between Cardiff and Swansea were resolved at Sunday lunchtime.
Replacement buses were available between St Austell and Newquay but First said road conditions were so bad in Wales that it could not provide an alternative.
First Great Western said tickets valid for travel on 23 December will be valid for journeys on 24 December.
The company is advising passengers to check their website for the latest information.