A Network Rail source has confirmed to the BBC that their chief executive, Sir David Higgins, will leave the company "at some time next year".
He has been credited with improving relations between Network Rail, the government, unions and the rail industry.
Sir David joined Network Rail, which is responsible for the UK's track, signals and stations, in February 2011.
He previously ran the authority which staged last year's London Olympics.
Manuel Cortes, leader of the TSSA rail union said that Sir David "had done a good job in difficult circumstances".
"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." Mr Cortes added.
Source: BBC News - Business http://www.bbc.co.uk/news/business-23443396#sa-ns_mchannel=rss&ns_source=PublicRSS20-sa
