Use as post office railway In 1911, a plan evolved to build an underground railway long from
Paddington to
Whitechapel serving the main sorting offices along the route; road traffic congestion was causing unacceptable delays. The plan was approved by the '''''' (
3 & 4 Geo. 5. c. cxvi). The contract to build the tunnels was won by
John Mowlem and Co. Construction of the tunnels started in February 1915 from a series of shafts. Most of the line was constructed using the
Greathead shield system, with limited amounts of hand-mining for connecting tunnels at stations. The main line has a single diameter tube with two tracks. Just before stations, tunnels diverge into two single-track diameter tunnels leading to two parallel diameter station tunnels. The main tube is at a depth of around . 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. During 1917, work was suspended due to the shortage of labour and materials. By June 1924, track laying had started, and additional time was granted by the '''''' (
14 & 15 Geo. 5. c. lxxx). 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. It was not until 3 August 1965 that the new station and office were opened by the
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. The railway was closed on 31 May 2003. In April 2011, an
urban exploration group called the "Consolidation Crew" published accounts of illicit access to the tunnels. Detailed photography and text revealed that the railway was still largely in good condition, despite some natural decay. Later, media were admitted to the tunnels as part of the pre-launch publicity for the Postal Museum. Photographs showed much of the infrastructure in place. A team from the
University of Cambridge took over a short, double track section of unused Post Office tunnel near
Liverpool Street Station, where a newly built tunnel for
Crossrail is situated some two metres beneath. The study is to establish how the original
cast-iron lining sections, which are similar to those used for many miles of railway under London, resist possible deformation and soil movement caused by the new works.
Digital cameras,
fibre optic deformation sensors,
laser scanners and other low-cost instruments, reporting in
real time, have been installed in the vacated tunnel. As well as providing information about the behaviour of the old construction materials, the scheme can also provide an early warning if the new tunnel bores are creating dangerous soil movement.
Redevelopment and preservation In October 2013, the
British Postal Museum & Archive announced that it intended opening part of the network to the public. After approval was granted by
Islington Council, work on the new museum and the railway began in 2014. Special tourist trains were installed in late 2016. It was planned to open a circular route, running beneath the depot at Mount Pleasant with a journey time of around 15 minutes, by mid-2017. The museum opened on 5 September. In its first year of operation (2017–2018), the trains performed 9,000 trips totalling , with the railway and museum hosting over 198,000 visitors. ==Rolling stock==