Northern line

The Northern line is a London Underground line, coloured black on the Tube map. For most of its length it is a deep-level tube line. It carries about 252,310,000 passengers per year, making it 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 that zone.