This ghost track is close to my heart, Crystal Palace race track on the site of Crystal Palace park.
This track was in use up untill 1973, both my parents spectated there and more recently a small section of the track was re opened for once yearly sprint events, staged betwean 1997 and 2000. No chance now of returning it to being a race circuit, its deep in the heart of a large residential area in South London and parts of the old circuit have been narrowed to become cycle paths.
If you look at the aerial photo below you can still see the basic track outline.
http://www.multimap.com/map/photo.cgi?client=public&X=534500&Y=171000&scale=10000&width=700&height=400&gride=&gridn=&lang=&db=freegaz&coordsys=gb