For seventy-six years, starting from 1927, the London Post Office operated a fleet of driverless electric trains that scuttled around pairs of narrow gauge rails deep under the ground hauling mails between various sorting offices. The Mail Rail ran from the Paddington Head District Sorting Office in the west to the Eastern Head District Sorting Office at Whitechapel in the east, a distance of 6.5 miles. In between, it had eight stations, the largest of which was underneath Mount Pleasant. At its peak, the Mail Rail operated for 22 hours a day and carried 4 million pieces of mail in a single day.

Photo credit: Miles Willis/ The Postal Museum and Mail Rail