Capital & Counties Properties (Capco) has acquired Kier's share of its Solum Regeneration joint venture with Network Rail.
Network Rail established Solum in 2008 to attract private investment for its rail services.
It is also intended for the project to help bring development projects forward to regenerate underused land around major rail stations.
Property development director for Network Rail Stuart Kirkwood said Capco's expertise will help unlock further regeneration opportunities.
He added that his organisation's previous partnership with Kier has already led to major development work getting underway at Christchurch, Epsom and Walthamstow Central stations.
Gary Yardley, managing director and chief investment officer of Capco, said her company has gained valuable experience in creating new spaces, which it can bring to this project.
"We are delighted to be entering into this joint venture with Network Rail, which offers the opportunity to take forward significant urban regeneration schemes at key transport interchanges in London," she commented.