RAIL services on the west coast main line will be disrupted for the next few weeks due to storm damage on the route.
Engineers are carrying out repairs to the Lamington Viaduct, just outside Lockerbie, after it was damaged by Storm Frank.
One pier of the structure has been weakened and investigations into the full extent of the damage will continue until the end of next week, Network Rail said.
The viaduct is expected to be closed until the end of January.
First TransPennine Express and Virgin Trains services will be affected.
Phil Verster, managing director of Network Rail Scotland, said: “Our engineers have been working round the clock for the past few days, in extremely difficult conditions, to try and gain access to the viaduct so that we can understand the scale of the damage that has been caused by Storm Frank.
“While that assessment work is not yet fully complete, it is clear now that the damage is significant.
“We are already working on solutions as to how we get the viaduct fixed and allow us to safely run trains over it again.
“However, it is likely that it will take us to the end of January until we can reopen it. If we can get it opened earlier, then of course we will. However, customers should plan for the work to continue until the end of the month.”
Phil Bearpark, of Virgin Trains, said: “We will continue to provide a replacement coach service for passengers between Carlisle and Glasgow, and there is also an alternative train service running on a diversionary route - however this is a limited service and will also add around 90 minutes to the journey.
“Virgin Trains tickets are being accepted on our east coast services between London King’s Cross and Edinburgh, and also on Cross Country services between Birmingham and Glasgow.
“Passengers should expect these services to be much busier than usual, and anyone who can postpone or cancel their journey should seriously consider doing so. We will of course give a full refund for anyone who decides not to travel.”
Paul Watson, of First TransPennine Express, said: “Customers are advised to either travel via the east coast main line, changing from Manchester at York or Newcastle for services to Edinburgh or using the coach replacement services between Carlisle and Glasgow.
“We have lifted ticket restrictions and are strongly advising customers to check the details of their journey before travelling.”