Sadiq Khan has asked to take control of railway tracks and stations in London to pave the way for high-frequency services.
Transferring responsibility for the infrastructure on suburban rail lines from Network Rail to Transport for London (TfL) would be the first step towards creating a “turn-up-and-go” service at comparatively underused stations.
The proposals could result in services of up to 18 trains per hour on key routes and trains running every 10 minutes between town centres in south-east London.
The London mayor has previously called on the government to hand over the inner lines of train operating franchises, such as parts of Govia Thameslink Railway’s Southern network.
The new proposal to extend TfL’s control of tracks and stations comes as the government reviews the nationwide structure of rail.
The review’s chair, Keith Williams, has so far indicated he would favour individual, devolved solutions, bringing track and train operation closer together.
TfL and the mayor argue devolution could increase capacity and reduce journey times, allowing the transport body to prioritise investment where it is most needed.
The success of the London Overground, where passenger usage of some rail lines in the capital has increased by 700% in just over a decade since being incorporated into the tube map and ticketing system, could be replicated at stations particularly in south and south-east London, which have infrequent services.
Currently, large numbers of commuters bypass local rail stations to get the tube instead. The equivalent of 33 double-decker busloads of people travel daily to Brixton underground station rather than catching trains from nearer West Norwood, according to TfL, while there are fewer jobs and houses around rail stations than tube stops.
The deputy mayor for transport, Heidi Alexander, said the current rail franchise system was broken beyond repair.
“Transferring responsibility for key rail assets to TfL would be the first step towards a long overdue transformation of the transport network in south and south-east London,” she said.
“The time has come for the whole of London to have an integrated, frequent and reliable rail service fit for a global capital city, with a high-quality suburban metro which would also stimulate economic growth, new jobs and homes.”
A strategic case for “metroisation” of rail services, published by TfL, said a flagship route between Balham and Victoria could have up to 18 trains per hour. Services could run all day, every 10 minutes, from Victoria to Herne Hill and Lewisham, as well as between town centres in south-east London such as Orpington and Bromley, and on the Greenwich, Bexleyheath and Sidcup lines.
It also promised tube-level service on the East London and Sydenham lines, and simpler all-day, turn-up-and-go services on the Wimbledon loop line.