Charing Cross, Euston and Hampstead Railway

The Charing Cross, Euston and Hampstead Railway was opened in 1907, running from Charing Cross to Golders Green with a branch line from Camden to Highgate. The line was unusual for the depth of the tunnels, the deepest point is under Hampstead Heath where the line is 250 feet below the surface. In 1923 the line was extended to Hendon and then Edgware in 1924. In the same year the line was linked to that of the City and South London Railway which ran between Clapham Common and Euston via the City. After the lines joined further extensions were made (to Morden in the south, High Barnet and Mill Hill East in the north, and a link between Charing Cross and Kennington) and the two railways were integrated into one system. In 1937 the line was renamed as the Northern Line.