Two of the developers shortlisted for the redevelopments of Euston and Victoria stations have signed architects to masterplan their bids.
Land Securities has appointed Hamilton Associates to draw up its design for Victoria, and Stanhope has recruited John McAslan + Partners to work up its bid for both sites.
The appointments come just days after the developers were named by Network Rail, and are the first to be made public.
British Land, which is shortlisted for both projects, has also chosen an architect, but declined to reveal the practice's name.
Other shortlisted bidders for the projects, including More London, Grosvenor, Hines and Hammerson, are understood to have delayed choosing an architect until they have worked through the briefing documents, which were released last Friday.
The Victoria development is expected to include up to 75,000 m2 of mixed-use space. It is also likely to involve moving the bus station in front of the rail station underground.
Hamilton and Land Securities are already working together on a mixed-use scheme in Oxford Street
At the 15-acre Euston site, a mixed-use scheme of up to 400,000 m2 is planned.
Hamilton and Land Securities are already working together on a large mixed-use office and retail redevelopment at the western end of Oxford Street.
The architect's other high-profile schemes include Ask Developments' Central Spine site in Manchester, the developer's proposed northern headquarters for the BBC.
McAslan has long experience in redeveloping transport hubs, having worked on schemes at London King's Cross, Birmingham New Street, Piccadilly Gardens interchange in Manchester and several of the new Jubilee Line stations on the London Underground.