Tower Subway

The Tower Subway is a tunnel beneath the River Thames in central London, close - as the name suggests - to the Tower of London. Its alignment runs between Tower Hill on the north side of the river and Vine Lane (off Tooley Street) to the south.

It was designed and built by James Henry Greathead in 1870 using a cylindrical wrought-iron tunnelling shield he designed with Peter W. Barlow. The tunnel has an internal diameter of 7ft (approx 2m) and is 1430ft (410m) long. The entrance shaft at Tower Hill is 60ft deep, while that in Vine Lane is 50ft deep.

Originally intended to provide a cable car service beneath the river. As such, it was world's first underground tube railway, officially opened on 2 August 1870. However, the cramped, low-capacity subway proved uneconomic (lasting just three months) and the tunnel was converted to a pedestrian route. This became a very popular way to cross the river, averaging 20,000 people a week, but it was eventually superseded by Tower Bridge which was constructed almost directly above it.

In September 1888, the Subway briefly achieved a certain notoriety after a man brandishing a knife was seen in the tunnel at the time when Jack the Ripper was committing murders in nearby Whitechapel.

From 1896 the Subway fell into disuse but from the 1920s gained a new purpose as a route for hydraulic tubes and water mains. While the tunnel is no longer used for hydraulic tubes, it still carrys a water main; today the hydraulic tubes have been replaced by telecommunication cables.