Network Rail maintenance crews carried out emergency repairs over the weekend after torrential rain last week caused landslips and flash flooding on both the East and West Coast Main Lines.
Landslips forced the closure of the northern section of the West Coast Main Line between Cumbria and Glasgow.
Network Rail area general manager Stuart Middleton said: “We had several landslips, the worst of which was at Tebay, where we lost 30m of the cess ballast.”
He said that emergency repairs enabled the line to be reopened with a 32km/h speed restriction, but further work is needed before trains can run at their usual speed of 201km/h.
Rail services in the north east of England were also hit by flooding, landslips and scouring.
The East Coast Main Line was closed until Sunday morning, while repairs were carried out at Spittal, south of Berwick-upon-Tweed, and at Scremerston in Northumberland, where 400t of material was washed away.
The Newcastle to Carlisle route was also hit by a landslip at Haltwhistle forcing a reduced service on the rail line until Monday morning. Network Rail general manager Warrick Dent described the conditions as “atrocious”, and said: “Some of the damage is extensive and requires significant work to make good.”