MPs have called on the government to prioritise improvements to Ely rail junction.
The East of England All-Party Parliamentary Group said the upgrade would be the "key" to unlocking economic growth across Britain.
The group also suggested that upgrades would unlock "thousands of extra freight trains" from Britain’s busiest container port at Felixstowe, to serve distribution centres in the midlands, the north and Scotland.
Improvements would also increase the frequency of passenger services to places such as Peterborough, Ipswich and King’s Lynn, Norfolk.
In a letter to transport secretary Louise Haigh, the APPG has asked that the schemes are "prioritised", include the "early release" of funding to allow for detailed planning of the delivery.
MPs said there was "unprecedented support" from freight and logistics firms, businesses and local and combined authorities.
They said two organisations, England’s Economic Heartland, external and Transport East, external, had released an updated report, external on the benefits of Ely and Haughley upgrades.
Andrew Pakes, MP for Peterborough and Co-Chair of the East of England All-Party Parliamentary Group said: "Improvements to Ely and Haughley are key to realising the Transport Secretary’s strategic priorities: improving the performance of our railways, transforming infrastructure right across the country; and delivering greener transport.
"Alongside allowing more goods to be moved more efficiently right across the UK, improvements to Ely Junction will also unlock capacity for better rail services in Peterborough, supporting the regeneration of our city and helping to realise its significant economic potential.”
Charlotte Cane, MP for Ely and East Cambridgeshire, added: "The government needs to release the funds for the upgrades to the Ely junctions.
"Taking more freight by rail has economic and environmental benefits. Local residents have been left in limbo for too long, they deserve to know what is happening."
Dr Nik Johnson, Mayor of Cambridgeshire & Peterborough, added: “Ely means business. Open up Ely, and you open up a world of opportunity for Global Britain.
"Unblocking Ely will enable passengers and freight to move freely not just through the East but through the Midlands and the North, with benefit surging throughout the UK.
"There’s tremendous public backing for this high-reward and climate-friendly investment which would make life better for hundreds of thousands of people in many parts of the country. For too long, UK growth has been fettered by this problem and now is the time for action. Open Ely and open all the world.”
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