The Northern line is a line on the underground railway system, London Underground. It is coloured black on the Tube map.
it is mosly underground (deep lvl) and serves the southernmost and some of the northen most stations, running in a complex noth sout with branches arrangemnt because origianly it was built by lots of comanies. On par with the Jubilee line it is the deepest line. It uses simmilar stock to the jublee line as well (1955/ 1956 Stock).