A wish list of rail upgrades - including more frequent, faster services - largely depends on spending millions of pounds on a new bridge, according to experts.
Norfolk County Council has published its priorities for the region's rail network, calling for:
-Faster journeys on all routes
-New track at Ely and the Norwich-London line
-A new station at Broadland Business Park
-A new line between Dereham and Wymondham
-Norwich in 90 services every hour and more, faster Norwich to Cambridge trains
However, apart from some improvements at Ely junction, none of the priorities are currently funded.
And to run more frequent, faster services between Norwich, Cambridge and London, the swing bridge at Trowse will need to be replaced.
The bridge was originally built in 1845 but replaced in 1986 to a single track. Both Network Rail and Greater Anglia have said it needs to be doubled if they want more trains running in and out of the city.
In 2014 this newspaper reported that Network Rail, which carries out infrastructure improvements, may replace the bridge by 2024 but that is no longer going to happen.
It is instead spending £2.2 billion on the region's rail network between now and 2024 on things like replacing track and signalling.
The new bridge is expected to cost tens of millions of pounds but would be cheaper if replaced with a fixed bridge rather than a swing bridge which can open for boats.
At the moment the British Railways Act means the bridge must be able to open so that law would also need to be changed.
Jonathan Denby, Greater Anglia's head of corporate affairs, said their priorities were to run Norwich to Cambridge trains every 30 minutes, instead of every hour, and to improve speeds on the Norwich to London line.
They also want to run more Norwich in 90 services, but he said they cannot run more frequent trains without a new bridge at Trowse.
Norwich North MP Chloe Smith, who is on the Great Eastern Mainline taskforce, said she would be lobbying the Government to solve the problem of the swing bridge.
"We have done well to get the new trains," she said. "But I want to continue securing investment for the area.
"I want to see a faster, more reliable service. Passengers deserve better and it will bring the jobs of tomorrow to our city."
Norfolk Chamber of Commerce has also called for the swing bridge to be replaced describing it last year as "the number one infrastructure need" for the whole of the east. They said it would unlock investment for the region.
Mr Denby said other infrastructure also had to be upgraded to get faster trains to London, including more track at Colchester, upgrades to Haughley Junction in Suffolk and digital signalling. None of that has yet been earmarked for funding.
Meanwhile to achieve the council's aim of cutting journey times between Cambridge and Norwich to 70 minutes, Mr Denby said track had to be upgraded on that line as well as Ely junction.
The council's wish-list, outlined in its Rail Prospectus, also calls on Greater Anglia to improve punctuality to 93pc of trains, up from 89pc last year.
The council last put forward a Rail Prospectus in 2013.
Some of its priorities from then, which it wanted to see happen by 2019, have happened - including some Norwich in 90 services, improvements to stations, direct trains to Stansted and new trains - but many have not.
In 2013, they also wanted to look at building a new station at Broadland Business Park on the Bittern Line.
That is included in the latest Rail Prospectus.
The report states there would be benefits to opening the new station, but the council would have to take on some of the cost which it cannot do currently.
The council also wants to see journey times reduced by five minutes on the Bittern Line and trains to North Walsham every 30 minutes.
On the Wherry Line - between Great Yarmouth, Lowestoft and Norwich - they want improvements to stations and faster services.
A Network Rail spokesperson said: "We are absolutely committed to improving the railway for our passengers and to drive and support economic growth.
"In order to do this, we identify potential schemes to upgrade and improve the railway as part of our long-term planning process to put forward to funders."
The priorities put forward by the council are dependent on the Government giving Network Rail the money to fund it.
Martin Wilby, the council's cabinet member for highways and infrastructure, said: "Ultimately, we are dependent on Greater Anglia, Network Rail and the Government funding and delivering them.
"We will continue to press for improvements and for our fair share of rail investment in this region, so that the Government's attention is not just focussed on HS2 and proposals for the North."
Norfolk's eight Conservative MPs have all said they want Ely junction to be upgraded and more frequent Norwich in 90 services.
-The last wish list
The council last put forward its rail wish list in 2013.
A host of its priorities then have never happened, but some were achieved.
The 2013 Rail Prospectus included services to Norwich in under 100 minutes as well as better trains, all of which happened.
But the region remains in the slow lane on a series of other priorities which the council hoped would be completed by 2019.
They include Norwich to Sheringham services every 30 minutes, Ely junction upgrade and Norwich to Cambridge in 70 minutes.
Labour leader at the county council Steve Morphew, chaired a group ten years ago to put forward the business case to improve the region's rail. He said they warned then major infrastructure upgrades were needed.
Mr Morphew said the new trains should have come alongside network upgrades.
"We always needed both and one without the other was asking for trouble," he said.
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