City and South London Railway
The City and South London Railway is the first deep-level underground “tube” railway in the world. It was the first major railway to use electric traction. It was originally intended for cable-hauled trains but the contractor of the cables went bankrupt during construction. Therefore, a system or electric traction using electric locomotives was chosen instead, it was still considered an experimental technology. It opened in 1890 with six stations that ran for 5.1km in a pair of tunnels between the City of London and Stockwell which passed under the River Thames.
The diameter of tunnels restricted the size of the trains therefore small carriages with high-backed seating were designed and built for the system. The railway was extended several times north and south with a result of serving 22 stations over a distance 21.7km from Camden Town in north London, to Morden in Surrey.
In 1883, a bill was presented to Parliament for the construction of the City of London & Southwark Subway (CL&SS). The main promoter of the system was also the engineer of the railway, James Henry Greathead, who started the tunneling with the shield/segmented cast iron tube method. The railway was to run from Elephant & Castle, under the Thames to King William Street in the City of London. The railway received Royal Assent as the City of London and Southwark Subway Act, 1884. In 1886, the twin tunnels, originally 3.1m in diameter, were extended with an increase diameter or 3.2m.
The small dimension of the tunnels made it difficult to provide sufficient ventilation with the steam power that was used on London’s other underground railways. It was not feasible to use steam power for deep tube railways. By 1888 when the cable company went bankrupt significant progress had been made in engineering since the tunnels’ construction had begun (1886). Therefore, the chairman Charles Grey Mott decided to switch to electric traction. The solution adopted was electrical power that would be provided by a third rail beneath the train.