Funding for the electrification of the 16km branch between Oxenholme and Windermere has been confirmed by the UK Government.
Transport Minister Baroness Kramer said: “Electrifying this key rail link will support the vital tourism industry in the area and help us build a stronger economy in the Lake District and beyond.
“Over the next five years, more than £38 billion will be spent on improving and running the system, to provide better services for passengers.”
Network Rail will now develop a detailed plan for the work, which should be completed by 2017.
Other routes being electrified include Manchester to Liverpool, Preston, Leeds and York, plus Preston to Blackpool North.