Post Office Railway
The London Post Office Railway  was "mothballed" on the night of 30 May 2013. Main access and maintenance is via Mount Pleasant Depot . The core route it is paralleled for much of its length by the northern (eastbound) bore of Crossrail, built much later during the 2010s., less formally known as Mail Rail, is a deep-level tunnelled double-track narrow-gauge automated freight railway which runs east-to-west across London between Paddington and Whitechapel. The route runs via several former Royal Mail sites. It was opened in December 1927
Status on OpenStreetMap
The route is approximately in, but without the split tunnels at stations or the extensive reversing loops. Tours used to be held of Mount Pleasant station and depot during the 1990s, and the general layout and operation of the line is well-documented and well-known. The construction is early enough that the deposited plans are now out-of-copyright. For convenience it may be useful to FOIA one of the more recent GIS survey layers that are in circulation; these having been published extensively during the Crossrail development, the City of London's Pipe Subways survey. The City of London's plans for post-war rebuilding plans published in 1944 have the individual bores and should come out of copyright on 2014.
Gauge is 610mm, with a centrally-placed third rail at 440V DC. Depth is around 21 metres below the surface. The main tunnel route is double-track inside a 2.75-metre diameter tunnel. Single-track tunnels on station approach are 2.1-metre diameter, with the same size used for the turnback ballon-loops. Stations are generally four-track, with two tracks each side of a large island, and a large numbers of scissors crossovers to allow platform and "bypass" lines for each direction. Depot access into Mount Pleasant Depot is a steep double-track ramp, where the third-rail stops. The depot is laid with "tram style" rails in the floor, and power where needed is fed with drop-leads from a manually fed from an overhead trolley system.
- “The Post Office Underground Railway”. British Postal Museum & Archive .
- URS (December 2009). “City Of London Decentralised Energy & Pipe Subways Study Baseline Report”. p. 18 .
- “Subways and tunnels under the City of London”. Ian Visits. 14 April 2010 .
“Plate 1B: Map of London Railways and main subways”.