Orbirail

Orbirail was a name for a suggested orbital railway route around London.

It would have connected the extended North London Line, East London Line, the South London Line and the West London Line, possibly including the Gospel Oak to Barking Line. The combined line would have orbited London in Zone 2, Zone 3 and (possibly) Zone 4.

It is not to be confused with London's existing circular railway, the Circle line of the London Underground.

Until recently Orbirail had no official status as a planned project. However, the completion of Transport for London's London Overground on 9 December 2012 achieved substantially the same objective.

On 12 February 2009, Mayor Boris Johnson and Transport Secretary Geoff Hoon announced £75 Million to fund the southern extension of the Overground network between Surrey Quays and Clapham Junction as part of the East London line extension, creating the final connection of an orbital railway for London to be completed in time for the 2012 Olympic Games. However, the timeline published by TfL in April 2011 stated the line would not open until late 2012, well after the Olympics and Paralympics.

London's railway system was largely built in the 19th century, by competing private companies. The benefits of an integrated transport system were unknown at this time and each main-line railway company built its own terminus in central London and operated radial routes from that point. For example, Waterloo railway station in south-west central London is the focus of lines radiating out to the south and west. Meanwhile, metropolitan and suburban railways developed also on radial lines.

...
Wikipedia