Sir Bob Horton, Railtrack's chairman, is thought to be keen to bring in a new chief executive with a wider commercial background who can push investment in the rail network ahead more quickly. Although Railtrack said there was no conflict and would not comment on the timing of Mr Edmonds' departure, Sir Bob is believed to be dissatisfied over the slow pace of investment in infrastructure.
Under Mr Edmonds, Railtrack has also had increasingly severe public spats with the rail regulator, John Swift QC, and the Government. He joined the company, then British Rail, in 1960.
Railtrack, which has already employed London-based headhunter Spencer Stuart, is believed to be looking outside the rail and utility sector for a "big hitter" with broad commercial experience.
One observer said the change was welcome: "The problem with Railtrack is that it is still hide-bound by public sector thinking. British Rail has always looked for ways not to spend money and that is rather the feeling with John Edmonds.
"The company needs someone who wants to spend and is committed to investment - someone with a bit more flair and flexibility."
After floating in May last year, Railtrack was heavily criticised over low levels of investment in renewing and expanding the rail network. Analysts say that pressure from the rail regulator to make Railtrack more accountable and Transport Secretary John Prescott's recent hints that Railtrack is liable for the windfall tax increases pressure for change.
"Railtrack's boss should be someone who can negotiate firmly with the regulator, someone who's been around the block a bit more than Edmonds," another analyst said.
However, some analysts think Railtrack will find it hard to attract someone of the right calibre. One said: "I think there is a possible problem for someone coming into this culture from the commercial sector. Over the past six months Railtrack has gone backwards."
Pay will also be a factor. In 1995/6 Mr Edmonds earned pounds 136,000 basic salary and pounds 216,000 with benefits and bonuses: "They will certainly have to pay the new man more."