Signal Box: Liverpool Street London Underground

Summary

Signal box. Built in 1875 for the Metropolitan Railway to a design by McKenzie and Holland. Some later alterations including the removal of the original frame and levers.

Reasons for Designation

The London Underground Signal Box at Liverpool Street, constructed in 1875 for the Metropolitan Railway, is designated at Grade II for the following principal reasons:
* Historical interest: as a rare survival of a C19 signal box on the initial part of the London Underground system, the world’s first underground railway. Its unique survival at a central London railway terminus is extraordinary. It provides a link to the early days of the London Underground and evidence of the short lived spur which originally went from the Metropolitan Railway to the Great Eastern Railway’s station at Liverpool Street;
* Architectural interest: a bespoke design for the Metropolitan Railway by McKenzie and Holland, it is unusual in having glazing on all sides because of its location on what was originally a junction;
* Degree of survival: the box survives well, with some alteration including the removal of the original lever frame and blocking of the locking room arches. It is otherwise largely unaltered externally and retains much of its glazing and other internal features including a 1950s 15-lever Westinghouse Brake and Saxby frame and control panel;
* Group value: groups with the Grade II listed Liverpool Street mainline station.

History

From the 1840s, huts or cabins were provided for men operating railway signals. These were often located on raised platforms containing levers to operate the signals and in the early 1860s, the fully glazed signal box, initially raised high on stilts to give a good view down the line, emerged. The interlocking of signals and points, perhaps the most important single advance in rail safety, patented by John Saxby in 1856, was the final step in the evolution of railway signalling into a form recognisable today. Signal boxes were built to a great variety of different designs and sizes to meet traffic needs by signalling contractors and the railway companies themselves.

Signal box numbers peaked at around 12,000-13,000 for Great Britain just prior to the First World War and successive economies in working led to large reductions in their numbers from the 1920s onwards. British Railways inherited around 10,000 in 1948 and numbers dwindled rapidly to about 4000 by 1970. In 2012, about 750 remained in use; it is anticipated that most will be rendered redundant over the next decade.

The signal box at Liverpool Street was built in 1875 on the extension of the Metropolitan Railway (MR) from Moorgate to Liverpool Street to a non-standard design by McKenzie and Holland, one of the largest signalling contractors. It originally housed a 40 lever mechanical frame which was replaced in the early years of the C20 by a 20 lever Railway Signal Company Tappet frame. In 1954 a 15 lever Westinghouse Brake and Saxby frame controlled from a push button desk was installed. The box was closed as a signal box and converted to an interlocking machine room in 1956. It is still in use although controlled from Baker Street.

The MR was the world's first underground line, opened in 1863 to ease surface traffic congestion and provide a passenger link between London's main northern railway termini at Paddington, Euston and Kings Cross.

Details

MATERIALS: locking room of yellow stock brick in Flemish bond. Operations room is timber-framed with dado-height vertical weatherboarding and timber-framed horizontally-sliding sash windows. Hipped slate roof has overhanging eaves supported by curved timber brackets.

PLAN: two storeys with the operations room two bays long by a single bay wide.

EXTERIOR: located at the western end of the northern Metropolitan and Circle line platform. Low locking room with three blocked round-arched openings facing the track partly encased by later extension of the platform. The upper, timber-framed, operations room has glazing on all four elevations. This was because a short lived spur, the tunnel for which can be made out in the headwall behind the signal box, originally ran into the Great Eastern Railway’s station. The windows are six-pane, timber, horizontal sliding sash windows. Above the windows are panels with cut-out quatrefoil decoration. The operations room has entrances at both ends with glazed six-pane doors reached via modern steel steps. On the southern elevation is a folding timber ledge on steel brackets allowing for window cleaning. At the north-east corner the signal box is connected to the headwall of the station via a brick flue for the fireplace.

INTERIOR: the interior has dado matchboard panelling, boarded ceiling, fitted cupboards at the west end and original fire surround at north-east corner. It retains the 1954,15 lever Westinghouse Brake and Saxby frame and control panel. The locking room was not inspected.

Sources

Books and journals
Horne, M, The Metropolitan Line, (2003)
Kay, P, The Signalling Atlas and Signal Box Directory, (2010)
The Signalling Study Group, , The Signal Box: A Pictorial History and Guide to Designs, (1986)

End of official list entry

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