The Post Office Railway, when it started running in 1927, was the first fully automated driverless railway in the world, a full forty years before the Victoria Line started service in London in 1967. The railway below London became the main means of moving mail, with Mount Pleasant being the hub of the distribution system. Linking with London's main line stations most of the country's long-distance mail travelled via the Post Office Railway. The fascinating story of how it began, how it was built, and why it closed is told here in an accessible way that tries to cover a highly technical and innovative system in a way that is easy to understand. The railway closed in 2003, but that was not the end of the story. The Postal Museum took over part of the Mount Pleasant sorting office to tell the story of 500 years of postal history and to open Mail Rail again with specially built trains as a visitor attraction and the start of a whole new adventure. If you are a railway enthusiast, postal enthusiast, urban explorer or just interested in finding out more about one of London's best-kept secrets this book is a must read for you.