London's mayor is to take control of part of a rail network which will be crucial for the 2012 Olympic Games.
The franchise will end in November 2007
Ken Livingstone and Transport for London (TfL) will take over the running of Silverlink Metro in November 2007.
This includes services from Richmond to North Woolwich on the north London line which the government wants to increase the capacity of in time for the Games.
It is part of a move to give the mayor more control over rail services within Greater London.
Transport Secretary Alistair Darling said: "The Government, TfL and London 2012 are developing plans to greatly enhance the capacity of the line both in preparation for the Games and to leave a lasting legacy".
The current Silverlink franchise consists of Silverlink Metro services and Silverlink County services.
Silverlink Metro also runs services between Gospel Oak and Barking; Clapham Junction to Willesden Junction and local services between Watford and Euston station.
The Silverlink County services will form part of the new West Midlands franchise as announced last October.
Mr Livingstone said the announcement meant work could begin to revitalise London's overground rail services.
"In addition to improved services, my first priority will be station safety and security, which means putting staff back into the stations where the public want to see them," he said.
"Stations that are currently often understaffed or empty altogether will be staffed adequately, offering passengers a more visible and reassuring presence."
He also said that security would be improved at stations and on trains by introducing CCTV.