August 2: When humanity first moved underground
On August 2, 1870, the Tower Subway opened in London, the world's first underground tube railway, bored beneath the Thames. Tonight's film: 12 Monkeys (1995).
There is a thought that always catches me when I turn to a day like this in the calendar. It is not the loud, grand things that grip me, it is one small, quiet gesture that later shapes everything. Tonight is one of those days.
On Tuesday, August 2, 1870, the Tower Subway opened to passengers in London. A 1,340-foot, roughly 410-metre bore under the River Thames, between Tower Hill on the north bank and Pickle Herring Stairs on the south. It was not grand: a single wooden carriage was winched back and forth on a 2 ft 6 in, 762 mm narrow-gauge cable railway. One car, moving non-stop between the two banks. The authorising Tower Subway Act 1868 had received royal assent on May 29, 1868.
What matters is not the size, it is the seven-foot, 2.1-metre diameter cast-iron shield used to drive the bore through the London clay. James Henry Greathead built that shield from a design Peter W. Barlow had patented in 1864. And that shield was the breakthrough: it made it possible, for the first time, to bore a deep tunnel safely through soft ground, under a river. Greathead’s shield became the template for every tube tunnel dug after it. Every modern metro descends from this shield and this tunnel.
