Editing Holborn (Piccadilly) signal cabin

{{Infobox signal cabin
|name = Holborn (Piccadilly)
|image = 
|imagesize = 300px
|cabin_code = D
|opened = 15 December 1906
|closed = 1 March 1980
|operator = [[London Underground]]
}}Holborn (prefix D) was a signal cabin located within the station of the same name on London Underground’s Piccadilly line. It was opened in 1906, re-fitted circa 1930, superseded in 1979 and closed in 1980. The 1930 lever frame is believed to be the example that resides at London Transport Museum, Acton Depot under the adopted pseudonym of York Road as a demonstrative exhibit. The 1979 lever frame has also been preserved at Acton Depot in an operational capacity as part of the Acton Miniature Railway.

== Great Northern Piccadilly & Brompton Railway ==
The signal cabin came into use on 15 December 1906 on the inaugural section of the Great Northern Piccadilly & Brompton Railway (GNPBR) between Hammersmith and Finsbury Park. The signal cabin was equipped with an electrically interlocked Westinghouse B-style miniature lever frame of 19 levers. Whilst the GNPBR station at Holborn and the signal cabin were built with four platforms and a junction for the Aldwych Branch, this was not ready at the time instead opening on 30 November 1907.<ref name=":0">Horne, Mike (2020). [http://www.metadyne.co.uk/pdf_files/LTSB_new.pdf Inventory of Signal Cabins and Other Interlockings]: London Transport Railways</ref> The GNPBR was a subsidiary of Underground Electric Railways of London (UERL) which by 1907 also owned the District, Baker Street & Waterloo and Charing Cross, Euston & Hampstead railways.<ref>Wolmar, Christian (2005) [2004]. The Subterranean Railway: How the London Underground Was Built and How It Changed the City Forever. Atlantic Books. <nowiki>ISBN 1-84354-023-1</nowiki>.</ref> <ref>Badsey-Ellis, Antony (2005). London's Lost Tube Schemes. Capital Transport. <nowiki>ISBN 1-85414-293-3</nowiki>.</ref>Despite being the 2<sup>nd</sup> station in the Holborn area and being near the Central London Railway (CLR) at British Museum (opened 1900), the two stations were not linked, and passengers had to change at street level.<ref name=":1">Bruce, J. Graeme; Croome, Desmond F. (2006) [1996]. The Central Line. Capital Transport. <nowiki>ISBN 1-85414-297-6</nowiki>.</ref>

Despite some persistent marketing and publicity, the line to Aldwych failed to generate any substantial traffic and would spend most of its operational life as a self-contained shuttle service. After a mere 8 years in 1914, the dead-ended platform at Holborn and a similar one at Aldwych were taken out of use leaving the single line layout that remains to this day.<ref name=":1" /> By 1930, the lever frame of Holborn (Piccadilly) was reduced in size to 11 levers in response to the reduction of platforms, signals, and points for the Aldwych Branch. No records from the time survive although it is thought that a switch of lever frame occurred. At around the same time, the lever frame at Hendon Central was being decommissioned due to the plain lining of track in the area. It was also a Westinghouse B-style frame of 11 levers and at just 7 years old would have been considered ideal for modification for use in a new location. It is believed that this frame replaced the original at Holborn (Piccadilly).<ref name=":0" />

== London Transport ==
In 1933, London’s independent Underground lines were taken into public ownership through London Passenger Transport Board under the public brand of London Transport. With this unification of the network came a desire to iron out some of the historic deficiencies of the network caused by private competition. The Piccadilly and Central lines at Holborn and British Museum stations was one such example with the railways crossing on a north-south and east-west axis generating significant interchange traffic early on. Holborn station was subsequently expanded with additional platforms and interchange corridors to accommodate the Central line coming into use on 25 September 1933 with British Museum station having closed a day earlier.<ref>Rose, Douglas (1999). The London Underground, A Diagrammatic History. Douglas Rose/Capital Transport. <nowiki>ISBN 1-85414-219-4</nowiki>.</ref>

The interwar years of London Transport marked the zenith of the proliferation of signal cabins on the Underground with lines operating a dense network of single cabins overseeing small geographic areas in line with the technological advances of the time. Whilst the sub-surface lines were able to build physically larger signal cabins early on with relative ease, this was not the case on the deep-level lines. The cramped nature of the tunnels coupled with the historic tendency to locate signal cabins within head walls or in the small confines between tunnels limited their size from the outset. As a result, lines such as the Piccadilly would continue to retain an expansive network of decentralised signal cabins till the late 1970’s.

It was the continued developments in automated programme machines pioneered at Earl’s Court control room by London Transport in the 1960’s that finally enabled closure of the remaining signal cabins on the Piccadilly line. Instead of being constrained to a small geographic area, signallers could oversee the running of entire lines from large amphitheatre style control rooms. Programme machines could automatically set routes and signals to a pre-loaded timetable with human intervention only required in the event of disruption. Despite Holborn (Piccadilly) signal cabin being earmarked for imminent closure, on 15 July 1979 the lever frame was replaced by a Westinghouse N-style frame also of 11 levers next to the existing building. The replacement frame was assembled using segments from the recently decommissioned LT signal cabin at Drayton Park. This operated for less than a year before closing on 1 March 1980 when Earls Court control room assumed remote supervision for this area via an Interlocking Machine Room.<ref name=":0" />

== Preservation and Historical Theories ==

=== Westinghouse B-style frame (1930-79) ===
This lever frame passed into the collection of the London Transport Museum before its opening in 1980. Intended to operate as an exhibit highlighting the operation of electro-mechanical interlocking, several non-standard modifications were made to it. The diagram was heavily altered to show a single direction branch and station with a diverging junction just beyond it, a layout that has never existed on the Underground for lever frame of this kind. It was also given the pseudonym of York Road which further concealed its original identity.

Later publications have wrongly attributed this lever frame to the station of the same name on the Piccadilly line. York Road tube station had closed due to low patronage in 1932 but its signal cabin remained fully operational until 1964 when the both the lever frame and crossover it controlled where removed for disposal. There have also been theories that suggest that the lever frame never saw operational use and was purely built as a demonstrator for Westinghouse Brake & Signalling Company who named the frame after their London headquarters. This has also been debunked since the London offices of Westinghouse were located at York Place not York Road and the high number of spare levers (6 out of 11) suggests operational use as a custom-built demonstrator would never have been built with such excessive redundancy. It is for these reasons that Holborn (Piccadilly) is believed to be the source for the lever frame with its early history of rationalisation.

In August 2021, the lever frame was showcased in the TV documentary series, Secrets of the London Underground. Charlotte Monroe, the final Service Operator to work at Edgware Road signal cabin, made a guest appearance explaining the operation of conventional signalling on the Underground.

=== Westinghouse N-style frame (1979-80) ===
After seeing brief service at Holborn, the section of N-style lever frame also found its way into the collection of London Transport Museum albeit in disassembled form. It would remain in this state until the late 2000’s when the kit of parts was used to construct a lever frame for the Acton Miniature Railway at London Transport Museum, Acton Depot. 

== References ==
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[[Category:London Underground]] [[Category:Signal cabins]]