LUL intends to award a contract in 2012 to build a single signal control centre for the whole of the sub-surface network ( Circle, Metropolitan, and Hammersmith & City lines ).

The existing Charing Cross station on the sub-surface District and Circle lines was renamed Embankment.

The station was rebuilt in the late 1950s and reopened on 1 March 1959 linking the two ' Notting Hill Gate stations ' on the Circle and District and Central lines, which had previously been accessed on either side of the street, with a shared sub-surface ticket hall with escalators down to the Central lines.

The station is in two parts: sub-surface platforms opened in 1870 by the Metropolitan District Railway ( MDR ) as part of the company's extension of the Inner Circle eastwards from Westminster to Blackfriars and deep-level platforms opened in 1906 by the Baker Street and Waterloo Railway ( BS & WR ) and 1914 by the Charing Cross, Euston and Hampstead Railway ( CCE & HR ).

Of the MR's original stations, the sub-surface Circle and Hammersmith and City line platforms are the best preserved.

The station is in two parts: sub-surface platforms opened in 1868 by the Metropolitan Railway and the Metropolitan District Railway as part of the companies ' extension of the Inner Circle route eastwards from Gloucester Road to Westminster and deep level platforms opened in 1906 by the Great Northern, Piccadilly and Brompton Railway.

The station is in two parts: sub-surface platforms opened in 1868 by the Metropolitan District Railway ( MDR ) as part of the company's first section of the Inner Circle route and deep level platforms opened in 1999 as part of the Jubilee line extension from Green Park to Stratford.

The Circle, Hammersmith & City and Metropolitan lines of the Underground system all use platforms in the sub-surface station, which has platforms 1 and 2, which are through platforms.

The station is in two parts: sub-surface platforms, opened in 1868 by the Metropolitan Railway as part of the company's extension of the Inner Circle route from Paddington to South Kensington and to Westminster, and deep-level platforms opened in 1906 by the Great Northern, Piccadilly and Brompton Railway.

It is a sub-surface station served by trains on the Circle and District Lines.

At this time Notting Hill Gate tube station was also redeveloped linking two stations on the Circle and District and Central lines which had previously been accessed on either side of the street with an entirely underground station enabling interchange between the deep level Central Line and the sub-surface Circle and District Lines.

The network was split into three parts — JNP ( Jubilee, Northern and Piccadilly Lines ), BCV ( Bakerloo, Central and Victoria Lines ) and SSL ( the sub-surface lines — District, Metropolitan, East London, Circle and Hammersmith & City Lines ).

# The first exploded on a Circle line sub-surface train, number 204, travelling eastbound between Liverpool Street and Aldgate.

# The second device exploded in the second carriage of another Circle line sub-surface train, number 216, which had just left platform 4 at Edgware Road and was travelling westbound toward Paddington.

Most of the District line's services use sub-surface D stock trains, although the Wimbledon to Edgware Road service is operated with C stock trains due to shorter platform lengths between High Street Kensington and Edgware Road.

The St Mary's curve connection between the District Line track and the East London Line was used for passenger traffic until 1941 but was subsequently only used to transfer empty trains to and from the other sub-surface lines.

Mile End is the only subterranean station on the network that offers cross-platform interchange between ' tube ' ( Central Line ) and ' sub-surface ' ( District and Hammersmith & City Line ) trains.

These companies, along with the sub-surface Metropolitan Railway and Metropolitan District Railway, criss-crossed beneath the city streets, competing with one another for passengers as well as with the new electric trams and motor buses.

It is a " sub-surface " line, running through the central area in shallow cut-and-cover tunnels.

Although passenger services via this spur ceased in 1941, it was retained to transfer empty trains between the East London line and the rest of the sub-surface network

In 1897 the MDR obtained parliamentary permission to construct a deep-level tube railway running between Gloucester Road and Mansion House beneath the sub-surface line.

The new line was to be an express route using electric trains to relieve congestion on the sub-surface tracks.

The sub-surface station is connected to the open-air Metropolitan line station.

To relieve the congestion, the MDR planned an express deep-level tube line starting from a connection to its sub-surface tracks west of Gloucester Road and running to Mansion House.

The construction of the deep-level station involved the excavation of a deep void around and beneath the sub-surface station to house the escalators to the Jubilee line platforms.

To relieve the congestion, the MDR planned an express deep-level tube line starting from a connection to its sub-surface tracks west of Gloucester Road and running to Mansion House.

In 1897 the MDR obtained parliamentary permission to construct a deep-level tube railway running between Gloucester Road and Mansion House beneath the sub-surface line.

The new line was to be an express route using electric trains to relieve congestion on the sub-surface tracks.

Here a Metropolitan line London Underground A60 and A62 Stock | A Stock sub-surface train ( left ) passes a Piccadilly line London Underground 1973 Stock | 1973 Stock tube train ( right )

The loop was constructed from a large excavation north-west of the MDR station and was connected to the sub-surface line with escalators.

Only one intermediate station was planned, at Charing Cross, below the sub-surface platforms.

A single platform was constructed on the northbound return section of the loop, and escalators were installed between both sets of deep-level platforms and the sub-surface station.

" For the opening of the CCE & HR extension, the deep-level parts of the station were named Charing Cross ( Embankment ) although the sub-surface platforms remained as Charing Cross.

In 2008 TfL proposed a project to provide step-free access to the sub-surface platforms.

When the station was rebuilt in 1933 with escalator access to the platforms, a new sub-surface ticket hall was built to the west under the roadway and new station entrances were constructed on the corner of Piccadilly and Stratton Street and on the south side of Piccadilly.

Today's sub-surface underground platforms, further west, were opened in March 1941, but Widened Lines services continued to use the original station until 1979.

alt = Diagram of original and current layout of platforms of sub-surface station showing changes in platform usage and numbering and change in location of tracks

The arcaded station entrance and shops, the brick retaining walls to the sub-surface platforms and the Exhibition Road pedestrian tunnel are Grade II listed structures.

A variety of underground and mainline services have operated over the sub-surface tracks, but the original station was completely rebuilt in conjunction with the construction of the deep level platforms and Portcullis House which sits above the station.

During the works, the level of the sub-surface platforms was lowered to enable ground level access to Portcullis House.

The new station initially operated as part of a combined station with the Metropolitan Line's adjacent sub-surface Swiss Cottage station ( platforms 1 and 2 were Metropolitan Line and 3 and 4 were Bakerloo Line ) but the Metropolitan Line station was closed on 17 August 1940

It was not possible to construct the inclined escalator shaft between the platforms and the existing entrance and so a new sub-surface ticket hall was constructed below the road junction.