The chief executive of Network Rail (NR) is to resign after three years in the job, saying it was a "good time" to move on.
Iain Coucher, 48, who has been at the rail infrastructure firm for eight years, will remain in his post over the coming months and will be involved in the search for his successor.
NR's chairman Rick Haythornwaite said Mr Coucher had been an "outstanding leader", adding that the railways had been "transformed" during his time at the company.
But Bob Crow, general secretary of the Rail Maritime and Transport (RMT) union, said Mr Coucher had presided over a culture that had attacked jobs, working conditions and rail safety while his salary and perks had "gone through the roof".
NR was reportedly set for a clash with the new Government over the payment of bonuses to staff and senior managers.
The rail infrastructure operator is due to announce its staff bonuses at the end of the month, leading to speculation that senior staff could receive hundreds of thousands of pounds on top of their salaries.
Last year, Mr Coucher waived his annual bonus of around £300,000 but still received £150,000 as part of a three-year rolling management incentive scheme on top of his salary of around £600,000.
He said on Thursday: "I am enormously proud of what the Network Rail team has achieved over the past eight years. Britain's railway is now on a sure footing for the future.
"Following three years as chief executive, and five before that as deputy, now is a good time for me to move on. The company needs continuity of leadership throughout the next five-year regulatory review period. Leading the thousands of dedicated railwaymen and women that make up this company has been the greatest privilege of my professional life. I know that under the management team we have in place, complemented by a new chief executive, they will continue to go from strength to strength in the future."
Mr Haythornthwaite, said: "Iain has been an outstanding leader for Network Rail both as chief executive and deputy chief executive. During his time with the company Britain's railway has been transformed with improved punctuality, which is at record levels, safety improved and billions removed from the company's costs through efficiency saving. What was a company with enormous problems in 2002 is a strong and stable one today, and Britain's rail users and taxpayers are the main beneficiaries."