Under the contract, the ATC consortium will design and install track, overhead lines and mechanical and electrical equipment to fit out the 21km of twin tunnels currently being bored under the streets of London.

Design work will commence immediately, with the fit-out works starting in 2014 on the entire tunnelled and surface sections of the Crossrail route between Royal Oak, Pudding Mill Lane and Plumstead Portals.

Costain also confirmed a separate joint venture with Alstom has been awarded the £15m contract for the design, construction and commissioning of the system that will provide traction power for the trains in the central tunnelled section of the Crossrail scheme.

Work will involve the construction of several auto-transformer stations and a feeder station site at Pudding Mill Lane to provide a 25 kV supply to the overhead line equipment that will power the new Crossrail trains.