Ministers have insisted they support efforts to improve the rail links between Norfolk and London, but can’t yet say when a key upgrade of the line will be carried out.
But campaigners say they are encouraged by the latest comments to emerge from the Department for Transport this week.
Last month, politicians and business leaders joined forces to urge the Department for Transport to commit to an early upgrade of the Ely North junction.
The work is seen as crucial to enable half-hourly services to operate between King’s Lynn and London King’s Cross, as well as improvements to other services using the link.
The fate of the project has been unclear after transport secretary Patrick McLoughlin announced a review of Network Rail’s construction programme in the summer.
That review, which is being led by the company’s new chairman Sir Peter Hendy, is expected to report this autumn.
In a letter to South West Norfolk MP Elizabeth Truss, which was released on Tuesday, Mr McLoughlin said: “I do not want to pre-empt his findings, but I do recognise the extent of your support and the concern you have expressed to ensure the upgrade continues.
“The growth in rail demand in East Anglia is substantial and our franchise plans recognise this.
“I am strongly supportive of the efforts being made to generate economic growth through new and enhanced rail services.
“I have asked my officials to continue to work with you on this, once Sir Peter has reported back to me.”
Ms Truss said: “The upgrade of the Ely North junction will drive forward investment in South West Norfolk and provide a massive economic boost to the region.
“I am pleased that the Transport Secretary recognises the growth in the East Anglia rail network.
“I will continue to ensure the upgrade remains on track and will work with the DFT, MPs, councils and the business community in order that local residents and visitors can benefit from half hourly trains on the Kings Lynn to London line and increased services on the Thetford route.”
And Colin Sampson, chairman of the Fen Line Users Association praised the “terrific fight” being put up by MPs, council and business leaders on the issue.
He said: “We are encouraged by all that we hear from that pressure group.”