Troubled construction giant Carillion is among the firms awarded contracts for the building of phase one of the HS2 rail line, the Government has announced.
The deals are worth £6.6 billion in total and will see tunnels, embankments and viaducts constructed between London and Birmingham.
The work is estimated to support 16,000 jobs.
A partnership featuring Carillion has been commissioned for two of the projects.
The firm's share price tanked by more than 70% last week after a profit warning and an £845 million write-off on construction contracts.
The final route of the Manchester and Leeds arms of the railway will be confirmed later.
Ministers suggested in November last year that the line should serve the existing Sheffield city centre station, after proposals to run trains to the Meadowhall shopping centre were shelved.
But critics have warned this will mean homes on the new Shimmer housing estate in nearby Mexborough being bulldozed.
Some residents found out about the HS2 plans just weeks after moving into the development of two and three-storey town houses.
A number of foreign firms were successful in bidding for the HS2 contracts, including Swedish-based Skanska, French company Bouygues Travaux and Austria's Strabag.
High-speed trains are expected to begin operating between London and Birmingham in 2026.
Transport Secretary Chris Grayling said: "This is a hugely important step in the construction of Britain's new railway and underlines this Government's determination to deliver an economy that works for all.
"HS2 will deliver vital links between some of our country's biggest cities, helping to drive economic growth and productivity in the North and Midlands.
"As well as providing desperately needed new seats and better connecting our major cities, HS2 will help re-balance our economy.
"We will now get on with building the railway, while continuing to ensure affected communities get appropriate support and are treated with fairness, compassion and respect."
Opponents of the £55.7 billion project claim it will run over budget, create havoc during construction and have disastrous environmental consequences.
Joe Rukin, of the Stop HS2 campaign, said: "The case for HS2 has been invented by the very cheerleaders who intend to rake in billions of taxpayers' money which is desperately needed elsewhere, so it really is time to ditch this gigantic white elephant before it is too late."
In February, Parliament granted powers to build the first phase of the line, which will see trains travel at high speed between London and Birmingham before running on from Birmingham on the existing West Coast Main Line.
Preparatory work has begun and major construction projects are due to launch in 2018/19.
Mr Grayling will soon publish a Bill to deliver Phase 2a from the West Midlands to Crewe, with services expected to begin in 2027.
Phase 2b from Crewe to Manchester, and Birmingham to the East Midlands and Leeds, is due to open in 2033.
Mr Grayling defended the cost of the project, insisting that "we are spending what it will take to deliver the best infrastructure in a way that is as sensitive as possible to the environment it's going through".
He told BBC Radio 4's Today programme: "Anyone who travels by train today knows that in and around our big cities the railway lines are congested and the trains are full.
"If we're going to free up the capacity of our mainline rail network, and that's what this is all about - it's about taking express trains off the existing railway line so we can run more commuter trains, more freight trains - then you're going to have to invest over the next decade and more to make sure that can happen."