Slightly off-topic but the Royal Mail used to run a network of nine 'Mail Rail' stations underneath London with small trains that moved general mail around. The

Slightly off-topic but the Royal Mail used to run a network of nine 'Mail Rail' stations underneath London with small trains that moved general mail around. They were discovered in 2011 by a group of photographers exploring abandoned tube stations. If you want more detail: http://www.placehacking.co.uk/2011/04/24/security-breach-london-mail-rail/ http://www.placehacking.co.uk/2011/04/24/security-breach-lon...