Network Rail chief executive Iain Coucher has resigned as chief executive after three years in the job.
He will remain in the post during the search for a successor.
Coucher has been with Network Rail for eight years, having previously been deputy chief executive.
Network Rail chairman Rick Haythornthwaite said: “The Board and Iain agreed that ,with Network Rail one year into a five year financial settlement, now is the ideal time in our financial and regulatory cycle for Iain to hand over to a new chief executive who will guide the company through the process of reviewing our funding with the Office for Rail Regulation for the next regulatory control period and address the next phase of challenges in its transformational journey.”
Coucher was chief executive of London Underground infrastructure company Tube Lines before joining Network Rail.