Services are beginning to resume at Preston after trains were suspended this morning due to debris on the tracks.
All services had been suspended after debris fell from the station roof and onto the tracks.
The disruption has affected all services through Preston, including Avanti West Coast, Northern and TransPennine Express.
Northern said severe weather has been to blame for the disruption, which has affected rush hour journeys from 7.50am.
But Network Rail said the cause of the debris from the roof is under investigation.
Network Rail said its engineers have assessed the roof and services are able to resume.
It initially warned passengers to expect major disruption until around 12pm, but some services are already running again.
Residual delays are now expected until 9.30am whilst services return to normal.