London’s underground railways date back to 1863 (being cut and cover construction) and the first tunnelled deep tube line, the City and South London Railway (CSLR), opened in 1890. This line ran between Stockwell and its city terminus (and railway company headquarters) in King William Street, which was the first Underground station to close in 1900, only 10 years after opening.

The line was built by James Henry Greathead, who had earlier built the Tower Subway using a modified design of Brunel’s tunnelling shield (used on the Thames foot tunnel from Wapping to Rotherhithe). The Tower Subway was a narrow-gauge railway, hauled using a cable system developed for San Francisco’s trams powered by stationary steam engines. Financially, it was a disaster, going bankrupt in less than a year. But its engineering was sound.

Greathead selected the same cable system for the CSLR, which permitted him to follow a tortuous route following the lines of streets on the surface to avoid paying fees to property owners above the line.

The above map, from Greathead’s paper to the Proceedings of the Institution of Civil Engineers¹, shows the line leaving King William Street (on the left) with two parallel tunnels, take a sharp turn (a 140 ft radius curve) and then the two tunnels align one above the other to stay within the limited width of Old Swan Street. They then dip down under Old Swan Pier (a gradient of 1 in 130) and traverse the Thames parallel again.

The tunnels were only 10ft 2in in diameter; somewhat smaller than that presently used on the deep tube network, being around 12 ft in diameter. Unfortunately, the cable contractor went out of business halfway through the construction of the line, so the forward-thinking board of the CSLR opted to use (what was then experimental) electric traction using small wheelbase locomotives.

Despite this setback, the line opened only four years after construction started, and by 1895 King William Street was being used by 15,000 passengers a day. However, there were problems associated with electric traction and the tortuous route. The Board of Trade had imposed a severe speed restriction on the curve leading into the station which was inconsistent with its approach up the steep gradient from under the river. So, drivers would descend under the river from the south side as fast as possible in the hope of having sufficient momentum to ascend the northern gradient and thence into the terminus. Often, they failed, and the train would roll backwards under the river for them to have another go, or to seek assistance from a ‘banker’ locomotive.

In 1900, the line was extended to Moorgate using new, larger diameter tunnels and a better alignment that replaced King William Street Station with a new one – Monument. The line formed the basis of the present Bank branch of the Northern line – being extended to Angel in 1901 and Euston in 1907.

Greathead’s statue stands outside the Royal Exchange, at Bank. The original tunnels still exist, and the access can be seen above the Northern line platforms at London Bridge. After closure, King William Street station and its tunnels provided extensive air-raid accommodation during the Second World War.

Since King William Street, a further 20 stations have closed, 13 have been re-sited or re-named and a significant number of street-level buildings are no longer in use. All casualties of economics.

Dr David Johnson FREng
Past Master, the Worshipful Company of Engineers

(based on his talk to the Worshipful Company of Engineers on 15th September 2020)

1.Greathead, J.H. (1895) The City and South London Railway; with some Remarks upon Subaqueous Tunnelling by Shield and Compressed Air Min Proc ICE Vol 123: 1895-96:Part 1, pp 39-73.
Image Credit: from Plate I of Greathead, J.H. (1895) (op. cit.) by kind permission of the Archivist, The Institution of Civil Engineers