"Opened in 1890, with 6 stations over 3.2 miles (5.1 km) and running in a pair of tunnels between the City of London and Stockwell passing under the River Thames, what was the first deep-level underground ""tube"" railway in the world, and the first major railway to use electric traction?"
City and South London Railway City and South London Railway The City and South London Railway (C&SLR) was the first 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
Tunnels underneath the River Thames Tunnels underneath the River Thames The table below lists many of the tunnels under the River Thames in and near London, which, thanks largely to its underlying bed of clay, is one of the most tunnelled cities in the world. The tunnels are used for road vehicles, pedestrians, Tube and railway lines and utilities. Several tunnels are over a century old: the original Thames Tunnel was the world's first underwater tunnel. The figure and list above leave out at least three tunnels: under the Thames Barrier; the 2.8m diameter tunnel carrying electricity cables from West Ham to the Greenwich Peninsula