The Post Office Railway, or the Mail Rail, was an automatic electric railway designed to streamline Royal Mail deliveries in London by bypassing the city's congested streets.
 
Early in the 20th Century, Royal Mail officials explored ways to make deliveries faster, and they found inspiration in Chicago's underground freight train system.
 
In 1927, after more than a decade of planning and work, the Post Office Railway finally opened for distribution.
 
In its heyday, the system carried millions of items of mail down a 6.5 mile underground stretch of track at speeds approaching 40 miles per hour with terminals at Paddington and Whitechapel.
 
The stations are much closer to the surface than the tunnels between them, to allow workers to bring mail to the surface quickly.
 
The system reached maximum capacity in the mid 20th Century, shuttling more than four million pieces of mail a day.
 
However, as time went by, the mail volume dwindled, and the railroad was no longer financially viable.
 
In 2003, the track was closed down and abandoned, and sealed off many entry points.
 
Since the end of July 2017, the site has been turned into the Postal Museum complete with a 20 minute ride on specially made miniature trains, however it is currently closed due to the pandemic.
 
James Bayley.