The Northern line is coloured black on the Tube map. The section between Stockwell and Borough opened in 1890, this is oldest section of deep-level tube line.
It is the second busiest line on the Underground. It is unique in having two different routes through central London – the Charing Cross branch, serving the central part of zone 1, and the Bank branch, serving the eastern part of zone 1. Despite its name, it does not serve the northernmost stations on the network; ironically serve the southernmost station. There are 50 stations in total and 36 are below ground.
The line has a complicated history, and the current complex arrangement of two northern branches, two central branches and the southern branch reflects its genesis as three separate railway companies that were combined in the 1920/30.
- Deepest station below street level is Hampstead at 58.5 metres
- Longest escalator is found at Angel and is 60 metres