Train services between Carlisle and Whitehaven have been cancelled after a points failure blocked the railway line.
Northern said services are unable to operate in either direction on Wednesday morning (November 11), with trains running through the affected area liable to cancellation or delays.
The disruption is currently expected to continue until around 8.15am.
Network Rail staff are on their way to the area to investigate and repair the fault, with further updates expected.
Passengers have been advised to take the next available Northern service to their destination where possible.
Northern has also temporarily lifted ticket restrictions in the affected area, including Advance and Peak restrictions, while the disruption continues.
Passengers delayed by 15 minutes or more may be entitled to compensation through Northern's Delay Repay scheme.
Travellers are being advised to check their journeys before setting off.
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