Crossrail has awarded the last of its major contracts to a joint venture including Costain, Alstom and TSO.
The £26m contract is for a maintenance facility at Plumstead, which will house the staff and the equipment required for the maintenance of the tracks and other infrastructure in the tunnels.
The JV was shortlisted in August 2015 along with Vinci Construction UK, Balfour Beatty and VolkerFitzpatrick.
However, VolkerFitzpatrick subsequently withdrew from the tender process in December 2015 and did not submit a bid.
Crossrail programme director Simon Wright said: “The procurement of billions of pounds-worth of work for the Crossrail programme has been a monumental exercise.
“We have used the procurement process as a way of ensuring world-class standards in the construction of the new railway as well as value for money for the taxpayer.
“The contracts we’ve signed with our principal contractors have also set the future standard for major UK infrastructure projects, helping us to deliver more than 550 apprenticeships, reducing our impact on the environment and spreading the economic benefits of the project.”
The maintenance facilities are due to be fully operational in August 2018.