The City and South London Railway (C&SLR) was the first successful deep-level underground "tube" railway in the world, and the first major railway to use electric traction. The railway was originally intended for cable-hauled trains, but owing to the bankruptcy of the cable contractor during construction, a system of electric traction using electric locomotives—an experimental technology at the time—was chosen instead. When opened in 1890, the line had six stations and ran for in a pair of tunnels between the City of London and Stockwell, passing under the River Thames. The diameter of the tunnels restricted the size of the trains, and the small carriages with their high-backed seating were nicknamed padded cells. The railway was extended several times north and south, eventually serving 22 stations over a distance of from Camden Town in north London to Morden in south London. Although the C&SLR was well used, low ticket prices and the construction cost of the extensions placed a strain on the company's finances. In 1913, the C&SLR became part of the Underground Group of railways and, in the 1920s, it underwent major reconstruction works before its merger with another of the Group's railways, the Charing Cross, Euston and Hampstead Railway, forming a single London Underground line called the Morden-Edgware line. In 1933, the C&SLR and the rest of the Underground Group was taken into public ownership. Today, its tunnels and stations form the Bank Branch of the Northern line from Camden Town to Kennington and the southern leg of the line from Kennington to Morden. Establishment 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 . The bill received royal assent as the City of London and Southwark Subway Act, 1884 on 28 July 1884. Section 5 of the Act stated: In 1886, a further bill was submitted to Parliament to extend the