Geograph - photograph every grid square

The London Underground system is also known as the "Tube". It is the oldest underground system in the world, the first section dating from 1863. The present system has over 250 miles of track and 272 stations. There are 11 lines covering Greater London, Essex, Buckinghamshire & Hertfordshire. Nearly half the system is above ground.
Wikipedia: Link
Transport for London: Link

A few years ago I read a book by Mark Mason "Walking the lines" in which he walked the route of the London Underground lines, overground. I will repeat this visiting all 272 stations (some more than once). My route tries to follow the line of the railway as closely as possible, using footpaths and roads, deviations are made to make the walk more "interesting".

Northwick Park is an Underground stationon the Metropolitan line. It lies between Harrow-on-the-Hill and Preston Road and is in Travelcard Zone 4.
It is served by 'slow' (all stations) trains only.
It is close to Northwick Park Hospital, the Harrow campus of the University of Westminster, and the suburb of Kenton.
The station opened in 1923.