Work to enable half-hourly trains to run between West Norfolk and London is set to take a year longer than expected to complete, according to a borough councillor.
Rail service chiefs say they are currently assessing what needs to be done to enable the upgraded service from Lynn to the capital to operate.
But West Norfolk Council leaders say they now understand a long-planned multi-million pound upgrade of the Ely North junction, which is seen as a key bottleneck on the route, will not be enough to deliver additional services on its own.
There has been growing concern about the future of the scheme in recent months, amid campaigners’ warnings that improvements to the line are not being delivered quickly enough.
And those fears intensified in June when ministers announced a review of the upgrade programme to be carried out by Network Rail, the company responsible for maintaining and improving the railway network, over the next few years, including delays to several major schemes.
But, earlier this month, the borough’s MPs, Henry Bellingham and Elizabeth Truss, said they had received assurances that the work would be completed by the end of 2017, following a meeting with rail minister Claire Perry.
The government’s contract with Great Northern, the current franchise operator, requires half-hourly services to run from the spring of 2017, subject to the completion of the necessary infrastructure works.
But Network Rail officials have again said they are committed to completing the Ely project, which is expected to cost around £25 million, during its current spending round, which will be completed in 2019.
And, in a report prepared ahead of Thursday’s full council meeting, environment portfolio holder Brian Long said of recent talks: “Network Rail have indicated an autumn 2018 completion for works at Ely North Junction and not autumn 2017, as stated by the Department for Transport.”
But he also said of the upgrade: “This work alone will not be sufficient to allow a half hourly service.
“In addition, level crossings will need upgrading along the line, not just at Ely North, but along the line to Lynn.”
Network Rail has previously confirmed that safety concerns at three crossings close to the junction itself would need to be resolved as part of the upgrade project.
And a spokesman said on Friday: “To achieve more frequent services, we need to consider the impact on level crossings on the King’s Lynn line, and this work is ongoing.
“We understand the importance of enhancing services in this area and are working hard to deliver this.”
A review of the project is expected to be completed this autumm.
But passenger groups have said they are worried that increasing public demand for rail travel is already outgrowing the current service provision and the problems will only get worse without swift action.