Trains running between Preston and Carlisle, Windermere and Barrow-in-Furness were still facing disruption at 10am due to damage to overheard wires on the West Coast Main Line.
The chaos has affected all three major operators on the West Coast Main Line - Avanti West Coast, Northern and TransPennine Express.
National Rail said the line from Preston north to Carlisle, Windermere and Barrow-in-Furness has reopened, but there remain delays to some services.
The Southbound line remains closed, but is expected to reopen later this morning.
Trains running between Oxenholme Lake District and Lancaster remain affected, with all services either cancelled or delayed.
No trains are able to run between Oxenholme, Carnforth and Lancaster until works are completed.
Teams of specialist Network Rail engineers worked overnight to repair damage to the 25,000-volt cables at Hest Bank between Lancashire and Oxenholme.
The complex electrical work to the overhead lines, which supply power to trains, was completed by 7am today (January 17).
But with trains and crews displaced for start of service this morning, passengers are being advised to check the status of services before they travel.
Network Rail has apologised to passengers for disruption to their journeys over the past 24 hours.
Phil James, director for Network Rail’s North West route, said: "I want to say sorry to passengers for the disruption and discomfort they faced making their journeys yesterday.
"The damaged overhead lines made travelling by train very difficult at times and we thank passengers for their patience while we worked hard to get people moving again.
"Everything was done to get things back up and running as fast as we could, with dozens of staff out fixing the damage and repairing the railway throughout the night, ready for today.
"Trains are running again this morning but please, check before you travel for the latest information."
Network Rail said the following services are running this morning.
Oxenholme to Windemere both directions.
Lancaster to Morecambe both directions.
Barrow to Carnforth both directions.
Skipton to Carnforth both directions.
Bus replacement services are running between Carnforth and Lancaster/Preston, leading to significantly increased journey times.
Passengers can check their journey with their train operator or at www.nationalrail.co.uk.