>> These modern day Londoners might communicate with texts or emails. But in the 1900s messaging here was done underground using London's abandoned mail rail, until now, hidden to the public. A network of postal tunnels and trains built in 1913, nestled in between London's tube lines, underground rivers, sewers and World War II bomb shelters.
Closed for over a decade, in its hay day it ferried more than 4 million letters every day between Paddington and White Chapel.>> I'm Reuter's Rosanna Filport at the point where the bulk of London's post divided, and made its way underground through the city. When these tunnels were being developed, people were still using horses and carts above ground, and this was the most instant form of messaging.
>> With up to eight deliveries a day you could send your friend a message at breakfast and be meeting for lunch at midday.>> The journey from one side of London to the other takes exactly ten minutes.>> It was a world first, there had been no previous electric railway with driverless trains.
>> The tunnel proved very useful in the first World War for storing heritage and artifacts. In the second World War, the important thing was to keep the mail moving, especially during nights of the Blitz, where transport above ground was being disrupted.>> But, as postage systems changed, many sorting offices closed and the mail rail became redundant.
Old trains went to what engineers here call the train graveyards. Now, the tunnel's opening to the public for the first time, with new trains for visitors to ride, and a postal museum. But that's just one part, and the majority of the line is still blocked off and unused, though many have tried to get involved.
>> A sort of a bicycle super highway was suggested once, but unfortunately that wouldn't work because the tunnels are just too low at points. The other was for deliveries to businesses in the west end, or alternatively even for mushroom growing. But unfortunately, we always meet the same problem, because the infrastructure was never meant for people.
It's so expensive to get people into even into position to get down and monitor mushroom growing.