Network Rail (NR) chief executive Sir David Higgins is set to step down, according to rail industry sources.
Sir David, who took over the job in February 2011, is understood to have decided that he will go some time after next year when a successor has been found.
It means a new boss will take the rail infrastructure company through its next five-year period from 2014-19 during which it will have to meet tough new train punctuality and financial targets set by rail regulators.
News of the exit of Sir David, an Australian who headed the UK's Olympic Delivery Authority, comes at a time when a new bonus scheme has been introduced for executives of the not-for-dividend company, which has no shareholders and which is effectively a public company.
This scheme was approved last week by NR's members who effectively act as shareholders in that they hold the board to account.
Under a new long-term incentive plan Sir David, who is on an annual salary of £577,000, and his fellow directors could get huge six-figure bonuses if certain targets are met.
NR would not comment on the future of Sir David who took over from Iain Coucher at the company.
Manuel Cortes, leader of the TSSA rail union, said: "Sir David Higgins has done a good job in turning NR around after the difficulties experienced under the previous regime.
"He removed its bullying culture and placed a new emphasis on safety which had been sadly lacking. He was not afraid to take on the 'old guard' who sadly wanted things to remain the same. He was slowly restoring the company's reputation and we would have liked him to stay around to finish the job he had started. He will be a hard act to follow."
Any of the top NR directors who leave before March 31 2015 will not be eligible for the long-term incentive plan bonus.