A programme manager will be appointed by the end of the year and main construction packages, under the NEC3 suite of contracts, will be tendered next year so work can start on site in 2010.
"Contractors will welcome the news that the Crossrail Bill has gained the Royal Assent and the enabling works are forecast to start as early as next year," said Civil Engineering Contractors Association (CECA) director Rosemary Beales.
Meanwhile, the City of London Corporation has urged the government not to use Crossrail as an excuse for failing to fund other much needed infrastructure upgrades in London.
"We want to see it, delivered, as part of a chain of infrastructure that includes an efficient Tube and rail networks and airports (especially Heathrow) that are fit for the 21st century," said the Corporation’s policy and resources committee chairman Stuart Fraser.
"Crossrail is vital, but delivering it should not become an excuse for cut-backs in other areas," said Fraser.
RMT general secretary Bob Crow warned that the rail union would be scrutinising the project to ensure it was "publicly accountable".
"We need to learn the lessons from the failures of privatisation and ensure that Crossrail
is a public project in every sense, publicly run and publicly accountable."