. "The Northern line is a London Underground line, coloured black on the Tube map. The section between Stockwell and Borough opened in 1890, and is the oldest section of deep-level tube line on the network.For most of its length it is a deep-level tube line. There were about 252,310,000 passenger journeys in 2011/12 on the Northern line, making it the second busiest line on the Underground."@en . . . "Northern line"@en . "58000.0"^^ . . "50"^^ . . "1890Z"^^ .