In November 1883, notice was given that a private bill was to be presented to Parliament for the construction of the City of London & Southwark Subway (CL&SS). The promoter of the bill, and engineer of the proposed railway, was James Henry Greathead, who had, in 1869–70, constructed the Tower Subway using the same tunnelling shield/segmented cast iron tube method proposed for the CL&SS. The railway was to run from Elephant and Castle, in Southwark, south London, under the River Thames to King William Street in the City of London. The tracks were to be in twin tunnels in diameter, running for a distance of .