The chief executive of Network Rail is to retire from the company later in the year.
Mark Carne, who joined the rail infrastructure giant four years ago, said he was timing the announcement so there was stability while the next five-year business plan was developed.
He said: "The men and women who run the railway are enormously committed and it has been a privilege to lead the organisation at a time of huge investment and transformational change. "
NR chairman Sir Peter Hendy said Mr Carne would submit the strategic business plan and lead discussions with the regulator.
"The timing of his decision ensures that a new chief executive will have time to get their feet under the table before the next regulatory period starts."
Transport Secretary Chris Grayling said Mr Carne had done an "excellent job", presiding over the biggest modernisation of the UK's rail infrastructure since Victorian times.