Floods have caused a wall to collapse on the West Coast Mainline at Caldew Maltings, near Carlisle.
A pylon carrying overhead cables has also become unstable.
All rail services north of Carlisle are currently suspended because of flooding.
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A 73-mile diversion will be put in place when a three-mile stretch of the A66 between Keswick and Penrith is closed for roadworks.
Mobile banking vans will be cut from eight communities in the Scottish Borders.
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