Passengers hoping to use the East Coast line between Edinburgh and Newcastle have been advised to postpone their trips after a series of landslips.
Severe wintry weather overnight in the Borders and north Northumberland also prevented train operators from providing replacement coach services.
East Coast, which operates trains on the route, said passengers should not travel for the rest of the day.
It said passengers could use valid East Coast tickets on the West Coast route.
An East Coast spokesman said: "We apologise to customers for the disruption to their journey today.
"Customers who choose not to travel today can do so when the East Coast route north of Newcastle reopens. Tickets for travel will be honoured where trains can operate.
"Weather conditions in the Borders and north Northumberland have been severe. Network Rail's engineering teams are doing everything possible to help us restore train services as soon as possible."