Train services between Barnstaple and Crediton will not resume until Monday at the earliest, according to Network Rail.
The Tarka Line will remain closed between Barnstaple and Crediton until inspections of two bridges have been carried out by specialist divers.
A spokesperson for Network Rail confirmed the divers were awaiting specific river-flow speeds before they could enter the water to check the structural integrity of the bridge.
Chris Denham, of Network Rail, said: “We had planned to check all of the bridges which needed inspecting yesterday but due to high water levels in the fast-flowing River Taw, the divers were unable to enter two of the bridges safely.
“The best way to check the bridges is to use divers so they can get down under the water and see if the flooding or debris has caused any damage to the foundations of the bridge’s piers.
“We do apologise for any disruption that people have endured on the Tarka Line. It has been the wettest year on record. Safety is our first priority and until we can ensure the track and bridges are safe, we will not let firms run trains on the line.”
Mr Denham said divers would attempt to search and inspect underneath the Umberleigh River Viaduct and the Black Viaduct at Great Fisherton Farm on Saturday.
However, the River Taw’s speed-flow needs to be at two knots or below to enable the divers to enter the water safely. It is currently flowing at four knots. If the river-flow does not reduce in speed on Saturday divers will be unable to inspect the bridges and the line may not re-open until mid-next week. The line will also remain closed if the bridges are deemed unsafe.
Mr Denham said: “We don’t know what we are going to find when we get down to inspect the bridges. They are not in danger of collapsing or anything but we need to check the structural integrity of each bridge.”
Inspections of two other bridges nearer to Exeter were carried out yesterday and the bridges were deemed safe.
The Tarka line has been closed since before Christmas. Replacement rail buses have been providing an amended service, and trains between Exeter St. David’s and Crediton have been able to resume after excessive flooding at Cowley Bridge was cleared.
Network Rail strongly advises anyone wishing to travel to or from Barnstaple on the Tarka Line on Saturday, Sunday or Monday to check the status of the services at www.nationalrail.co.uk.
Video: Engineering work at Cowley Bridge following severe flooding on the track in December. Video footage taken by Mike Yearworth on Sunday, December 23.