The track difference of the track layout of the London Underground and London Overground is whereas one is underground the other is over the ground.
it is neither in underground or overground. it is a separate system.
The London Underground did give the East London line to the London Overground to ease its traffic.
You can get an underground train and an overground train from London Bridge.
Well the easiest way would be to use the London Underground. If it is imperative to use a train there is the London Overground Network. A link to the Underground/Overground rail network can be found below.
There was too much overcrowding in central London to accommodate above ground rail lines into the city.
Take the Underground (tube) to Victoria and then the Overground (main line) to Eastbourne.
London Overground Rail Operations was created in 2007.
Transport for London (TFL) is the umbrella name for all of London's transport services which include underground, overground, DLR, taxis, hire cars, buses, trams etc.
The Circle line connects with all TFL "underground" lines. It does not (directly) connect with the Emirate Air Line (the cable car link between Greenwich and the Docks) and the London Overground (an "outer" circle line around London). (Both of these are marked on the Underground Map, the latter [definitely] operated by TFL.)
Merseyrail Similar to London Overground in terms of how they operate since they all offer railway services to the people.
Yes
tube lines: Bakerloo, Central and Victoria; Jubilee, Northern and Piccadilly; sub-surface lines: District, Hammersmith & City, Circle, Metropolitan, East London (currently in major refurbishment to become part of the London Overground)