The City & South London Railway becomes the first line to operate underground electric traction trains in 1890.

Part of the modern-day tube system’s Northern Line, the City & South London Railway started running underground electric traction trains in 1890.

Today, the London Underground – known as ‘the Tube’ due to the circular tunnels through which the underground trains run – carries around 5 million passengers per day. The Tube has 270 stations across 11 lines, and spans 250 miles (400 km) of track. In 2015-16, statistics show that the London Underground carries 1.34 billion passengers, making the network the 11th busiest metro system in the world.

In 1931, Harry Beck designs the Tube map, which in 2006 gains critical acclaim by being voted a national design icon. The branding of the Tube is very deliberate and distinctive. The station-designating roundels and Johnston typeface are the two most obvious examples of this.