Tower Subway

The Tower Subway is a tunnel beneath the River Thames in central London, between Tower Hill on the north bank of the river and Vine Lane (off Tooley Street) on the south. In 1869 a circular tunnel was dug through the London clay using a cast iron shield, an idea that had been patented in 1864 by Peter W. Barlow but never built. A narrow gauge railway was laid in the tunnel and from August 1870 a cable-hauled wooden carriage conveyed passengers from one end to the other. This was uneconomic and…