The Post Office Railway (Mail Rail), UK
Sealed off for nearly a decade, the folks at SilentUK have finally uncovered London’s secret ‘Mail Rail’, first opened in the 1920s after extensive and complicated construction. Closed down due to lack of use and high costs, the elaborate underground system became an urban legend for adventurers. For more photos, history, and the full story of the find, see: http://www.silentuk.com/?p=2792
From Wikipedia:
In 1911 a plan evolved to build an underground railway 6½ miles long from Whitechapel to Paddington serving the main sorting offices along the route; even then, traffic congestion was causing unacceptable delays. The contract to build the tunnels was won by John Mowlem and Company. Construction of the tunnels started in February 1915 from a series of shafts dug along the route. 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 tube of 9 ft diameter with two tracks. Just before stations, tunnels diverge into two single-track 7 ft diameter tunnels. These then connect to two parallel station tunnels of 25 ft diameter. The main tube is underground at a depth of around 70 ft.[5] 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.
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 developed for a new Western District Office at Rathbone Place which required a diversion to the line. The diversion came into operation in 1958.[6] It was not until 3 August 1965 that the new station and office was opened by the Postmaster General of the United Kingdom, Anthony Wedgwood-Benn. The disused section was used as a store tunnel; some parts of it still have the track in place.
Originally posted on poindexter, who?