Colas Rail and AECOM will work with Network Rail across the south of England, while a three-way joint venture of Babcock Rail, Arup and Arcadis will deliver upgrades in Scotland.

Deals are still subject to contract terms being finalised and agreed, with procurement currently operating a standstill period.

The bidding process for the remaining third regional alliance – Central region – is still underway with a preferred bidder due shortly following final verification and internal approvals.

The framework award for the next generation rail system contracts will be one of the most substantial of Network Rail’s CP6 contracts to be let.

Steve Featherstone, programme director Track, said: “Reaching this important milestone ensures we will have a stable foundation for the delivery of the Great Britain’s core railway infrastructure for the next decade.

“Our new strategy allows us to better align to the routes and ultimately, deliver for customers.”

Jean-Pierre Bertrand, CEO of Colas Rail said: “We are extremely proud of our team being recognised for the quality of the tender submission. We are fully committed to delivering major improvements to the UK railways in the South working together with our partners Aecom and Network Rail over the upcoming 10 years.”

This was echoed by Archie Bethel, Babcock International’s CEO: “Building on our long term relationship with Network Rail, we are delighted to have been selected as preferred bidder for this major programme of railway systems work, with our alliance partners Arcadis and Arup.  We look forward to working with Network Rail in the new alliance.”