The appointments, made last week, will be seen as a step forward for the controversial project, which has been dogged by delays since it was first considered in the 1980s.
Crossrail will run east-west across the capital, relieving congestion on the Central Line and other crowded London underground lines.
Trains would run from Maidenhead in the west through London to Abbey Wood and Shenfield in the east, with the potential for routes to Heathrow airport and Canary Wharf.
There would be stations in central London at Paddington, Bond Street, Tottenham Court Road, Farringdon, Liverpool Street and Whitechapel.
Ministers have in recent years encouraged the development of the scheme without formally committing the government to its construction. Legislation to pave the way for the project was preserved when parliament dissolved in April for the general election.
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Transport experts say the project is likely to have a complicated funding structure, with the possibility of a special London business rate being levied to help finance it.
A previous version of the project was killed off in 1990 by a committee of MPs.