Rail passengers between Blackpool and Preston are facing delays of up to an hour this evening.
A signalling fault at Lytham means some lines between Blackpool South and Preston are blocked.
And Northern says services may be cancelled or be delayed up to 60 minutes.
A spokesman said: "Please expect minor/major delays of up to 60 minutes this evening on services between Blackpool South and Preston due to a fault with the signalling system at Lytham.
"Road transport has been requested."