Editing London Post Office Railway (section)

===Use as post office railway===
{{London Post Office Railway}}
In 1911, a plan evolved to build an underground railway {{convert|6+1/2|mi|km}} long<ref>Romance of London's Underground, Ayer Publishing</ref> from [[Paddington]] to [[Whitechapel]] serving the main sorting offices along the route; road traffic congestion was causing unacceptable delays. The contract to build the tunnels was won by [[Mowlem|John Mowlem and Co]].<ref>{{cite web|url=http://www.time-capsules.co.uk/picture/number2132.asp|title=Sign in to Photo Forums|website=www.time-capsules.co.uk}}</ref> Construction of the tunnels started in February 1915 from a series of shafts. Most of the line was constructed using the [[Tunnelling shield|Greathead shield system]], with limited amounts of hand-mining for connecting tunnels at stations.

The main line has a single {{convert|9|ft|adj=on}} diameter tube with two tracks. Just before stations, tunnels diverge into two single-track {{convert|7|ft|adj=on}} diameter tunnels leading to two parallel {{convert|25|ft|adj=on}} diameter station tunnels. The main tube is at a depth of around {{convert|70|ft}}.<ref>{{cite magazine| title=London's Post-Office Railway| date =  March 1952| page =164|volume= 97| number= 3| issn = 0032-4558|magazine = [[Popular Mechanics]]| publisher =[[Hearst Magazines]]|url=https://books.google.com/books?id=yNwDAAAAMBAJ&pg=PA164}}</ref> Stations are at a much shallower depth, with a 1-in-20 gradient into the stations. The gradients assist in slowing the trains when approaching stations, and accelerating them away. There is also less distance to lift mail from the stations to the surface. At [[Oxford Circus]] the tunnel runs close to the [[Bakerloo line]] tunnel of the [[London Underground]]. The tunnel also runs under [[Selfridges]] as the recent 2018 refurbishment of the building revealed.<ref>{{cite web | url=https://www.ajbuildingslibrary.co.uk/projects/display/id/8258 | title=Selfridges London &#124; AJ Buildings Library }}</ref>

[[File:London Post Office Railway Map.jpg|thumb|Map of the Post Office Railway]]
During 1917, work was suspended due to the shortage of labour and materials. By June 1924, track laying had started. In February 1927, the first section, between Paddington and the West Central District Office, was made available for training. The line became available for the Christmas parcel post in 1927 and letters were carried from February 1928.

In 1954, plans were developed for a new Western District Office at Rathbone Place, which required a diversion, opening in 1958.<ref>New Tunnels for Post Office Railway ''[[Railway Gazette International|Railway Gazette]]'' 25 April 1958 page 495</ref><ref>{{Cite journal | last1 = Blackford | first1 = S. | last2 = Cuthbert | first2 = E. W. | doi = 10.1680/iicep.1960.11893 | title = Underground Station for Western District Post Office, London. (Includes Plate) | journal = ICE Proceedings | volume = 15 | issue = 2 | pages = 81 | year = 1960 }}</ref><ref>{{Cite journal | last1 = Collingridge | first1 = V. H. | last2 = Tuckwell | first2 = R. E. | doi = 10.1680/iicep.1960.11897 | title = Underground Station for Western District Post Office, London. (Includes Plates) | journal = ICE Proceedings | volume = 15 | issue = 2 | pages = 95 | year = 1960 }}</ref> It was not until 3 August 1965 that the new station and office were opened by the [[Postmaster General of the United Kingdom|Postmaster General]], [[Tony Benn]]. The disused section was used as a store tunnel; some parts of it still have the track in place.

In 1987, the railway changed its name to Mail Rail in celebration of its 60th anniversary, and some trains were rebuilt with more aerodynamic casings.<ref name="story"/>