Tube railways, which caused less disruption because they were constructed by boring a tunnel, arrived in 1890, with the opening of the City and South London Railway, a line from Stockwell to King William Street. It was planned as a cable-hauled railway, but the advent of electric traction resulted in a simpler solution, and the change was made before the cable system was built. It became the world's first electric tube railway. Although the system includes of track, only about 45 percent is actually below ground.