Contractors have worked round-the-clock to clear more than a thousand tonnes of mud and rocks which blocked the Westcountry's main railway line.
A landslip at Teignmouth sent about 1,500 tonnes of debris on to the tracks between Exeter and Newton Abbot on Wednesday night, blocking the way for trains.
Officials were last night hoping to reopen the westbound line in time for trains to start running again this morning. Network Rail said a train with 18 empty wagons had been sent to Teignmouth to remove material from the site.
"Progress is slower than hoped for because loose material is continuing to slide down the cliff face," a spokesman said.
"Staff are making the main slip site safe and erecting barriers."
Heavy rain and flood water loosened earth and prompted the collapse between Sprey Point and Parsons Tunnel. There were 13 other landslips nearby, mostly minor, with one designated a "medium risk".
To the east of Exeter, where the River Exe overtopped and completely submerged rail tracks, services remain severely limited.
The main line out of Exeter to the Midlands and the north of England has reopened but the flooding at Cowley Bridge junction continues to disrupt journeys.
Signals are being operated by hand with officials saying it could be up to two weeks before services are completely restored.
Two trains per hour are running through Cowley Bridge in each direction, with services delayed by 20 minutes.
Meanwhile, on the Tarka Line between Exeter and Barnstaple, work to lay new track is only half complete.
Services are due to resume on Monday but further closures will now be needed next year.