A number of firms have been shortlisted for contracts on the second phase of High Speed 2 (HS2) worth a total of £520m.
The £350m professional services contract will be fought out between four firms, while three will compete for the £170m programme development partner role.
The winners for both packages will be announced before the end of the year.
HS2 chief executive Simon Kirby said: “Phase two will significantly increase capacity, enhance connectivity and improve journeys for millions of people travelling between London, the Midlands and the major cities of the North.
“HS2 will be Britain’s largest infrastructure development, and has the potential to change the way the UK designs and builds projects of national significance.
“That’s why it’s so important that we get the right team on board to help us develop the design and environmental assessment that supports obtaining the hybrid bill powers.
“This process needs to start now so that we are able to open all the way to Manchester and Leeds on time.”
For the professional services package, joint ventures will compete between: Aecom, Capita and Ineco; Mott MacDonald and WSP Parsons Brinckerhoff; and Atkins and Arcadis, while Arup will tender as a sole bidder.
The winner will work on the design of sections of the route, from Crewe to Manchester as well as Birmingham to Leeds via Sheffield and the East Midlands.
Meanwhile, the three firms in the running for the phase two programme delivery partner will be CH2M, Bechtel and a joint venture between Mace and Turner & Townsend.
These firms will support development and submission of the phase two hybrid bill in 2019.
Mace and Turner & Townsend has managed projects including the Shard and London 2012 Olympics.
David Leam, infrastructure director of London First, said: "With ministers in go-slow mode on new nuclear, it’s more important than ever that government takes decisive action on other nationally important infrastructure projects such as HS2 and airport expansion.
"As a country we have historically under-invested in our infrastructure, much of which is now operating at full capacity. Pressing ahead with new railway lines and runways will boost economic activity by helping people find new employment and business opportunities – and in a post-Brexit context also sends a powerful signal that Britain’s door remains open to the world."