An interrupted train between Exeter St. Davids and Barnstaple has blocked all routes.
National Rail says there will be no trains to or from the train station by 10.30 in the morning.
Buses replace trains here until the train has been removed.
It is believed that the train collapsed on Thursday morning just before 7am.
Passengers will be faced with more disruptions as of next week due to tunnel upgrades and the replacement of tracks.
The closure of the Whiteball Tunnel near Tiverton Parkway, which lasts from Monday, February 18 to Friday, March 8, will sever the railway line to Devon and Cornwall, forcing passengers to take a bus between Taunton and Exeter.
The closure of one of the two tunnels in Marley near Totnes (which will also run from Monday, 18 February to Friday 8 March) – will be less disruptive, but will lead to a reduction in services – and replacement of trains by buses only day
The other works will also be less disruptive and limited to single days or weekends.
The CrossCountry website says, "A revised train service will operate between Exeter St Davids, Dawlish, Teignmouth, Newton Abbot, Totnes and Plymouth.
"Replacement rail traffic between Taunton and Exeter St Davids will operate on Monday, February 18. Road transport will operate on Sunday, February 17, between Newton Abbot, Totnes and Plymouth."
GWR announced this morning on Twitter: "From 18 February to 8 March, upgrade work will be carried out in Devon & Cornwall.
"Long-distance trains are being diverted, their journey times are being lengthened, and buses are being used at a reduced frequency to supplement some trips."
A tweet infographic indicates that from Monday, February 18, through Friday, March 8
- Buses replace trains between Taunton and Exeter
- Train services between Exeter and Plymouth will be reduced
- A shuttle train operates in Cornwall
- On February 17, buses will replace trains between Newton Abbot and Plymouth