Northern Line 

A selection of diagrams showing the signalling arrangements for sections of the Northern Line at different times throughout its history.

	Northern Line Extensions 1939-1941 A large diagram showing the details of signalling on the Northern Line between Archway and High Barnet when LPTB services were extended over the former Northern Heights Line in stages between 1939 and 1941. Make sure you zoom in to see all the detail.
	Northern City Line A pair of diagrams showing the signalling on the Northern City Line (Finsbury Park to Moorgate), both before and after the construction of the Victoria Line.

Most of the diagrams are in PDF format and to open them you will need Adobe Acrobat Reader. If you do not already have this it can be downloaded from the Adobe Website.