Network Rail said engineers have replaced the faulty signalling module, which has resolved the fault, and most services have now resumed.
But Northern said the fault, which allows trains to change tracks, has meant some services will continue be disrupted until around 10.15am.
A Northern spokesman said: "As a result, train services are unable to run between Preston and Blackpool North. But services are currently able to run to/from Blackpool South.
A number of rush hour train journeys were delayed to a signalling fault between Preston and Kirkham & Wesham stations this morning (Monday, December 6)
"Train services running between Preston and Kirkham and Wesham stations are returning to normal but some services may still be cancelled or delayed, with disruption expected until 10.15am."
The first service affected was the 5.19am from York to Blackpool North, which only arrived at the station at 8.09am.