All rail services between Carlisle and Workington have been cancelled.
Northern says a fault with the signalling system means they expect disruption until at least 5pm.
Problems have been ongoing since this morning.
All services running between the two stations will be cancelled.
Meanwhile, flooding in the signal box at Wigton means all lines are blocked between Maryport and Carlisle. A train service will operate between Barrow and Maryport in both directions.
A bus will provide a service between Workington and Carlisle in both directions.