Editing London Post Office Railway (section)

===Closure===
A [[Royal Mail]] press release in April 2003 said that the railway would be closed and mothballed at the end of May that year. Royal Mail had earlier stated that using the railway was five times more expensive than using road transport for the same task. The [[Communication Workers Union (United Kingdom)|Communication Workers Union]] claimed the actual figure was closer to three times more expensive but argued that this was the result of a deliberate policy of running the railway down and using it at only one-third of its capacity. A local governmental report by the [[Greater London Authority]] stated that the "line carries an average of four million letters and parcels per day" and was in support of continued use and criticized the increase of lorries on local roads, estimated to be 80 more truck loads per week.<ref>{{Cite web|url=https://www.london.gov.uk/sites/default/files/gla_migrate_files_destination/archives/assembly-reports-pubserv-mailrail.pdf|title=The future of Mail Rail|author=London Assembly's Public Services Committee|website=Greater London Assembly}}</ref> The railway was closed on 31 May 2003.<ref name="finalcall"/><ref>End of the line for Mail Rail ''[[Today's Railways UK|Entrain]]'' issue 19 July 2003 page 12</ref>

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 is still largely in good condition, despite some natural decay.<ref>{{cite web |url=http://www.placehacking.co.uk/2011/04/24/security-breach-london-mail-rail/ |title=Security-Breach: London Mail Rail|publisher=placehacking.co.uk |archive-url=https://web.archive.org/web/20110429171845if_/http://www.placehacking.co.uk/2011/04/24/security-breach-london-mail-rail/ |archive-date=2011-04-29 |access-date=2021-04-25 }}</ref><ref>{{cite web |url=http://www.silentuk.com/?p=2792 |title=The Post Office Railway (Mail Rail)|publisher=silentuk.com |archive-date=23 April 2011|url-status=usurped |archive-url=https://web.archive.org/web/20110423152336/http://www.silentuk.com/?p=2792|access-date=20 April 2011|date=18 April 2011 }}</ref> More recently, media have been admitted to the tunnels as part of the pre-launch publicity for the Postal Museum. Photographs show much of the infrastructure in place.<ref>{{cite web|title=Eight storeys down on abandoned tracks|url=http://leftoverlondoner.tumblr.com/post/160455903728/eight-storeys-down-on-abandoned-tracks|website=Leftover London|access-date=10 May 2017}}</ref>

A team from the [[University of Cambridge]] has taken 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 camera]]s, [[Brillouin scattering#Fiber Optic Sensing|fibre optic deformation sensors]], [[laser scanner]]s and other low-cost instruments, reporting in [[Real-time computing|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.<ref>{{cite web|title=Bridging the Knowledge Gap in London's 'Secret Tube'|url=http://www-smartinfrastructure.eng.cam.ac.uk/news/20140613BCIawardshortlist|publisher=Cambridge Centre for Smart Infrastructure & Construction|access-date=16 June 2014}}</ref>