In message , at
04:45:14 on Sun, 7 Apr 2013, contrex remarked:
http://traintimes.org.uk/map/tube/

There appear to be 2 secret lines in South London that are about 1 mile to the east & west of the Northern Line, with trains running at several
hundred miles an hour between approx Kingsway and Merton. Can anyone tell me how I can get a ride, because I am sure it would be very exciting?

I saw that too. Driven by Gremlins, perhaps.
--
Roland Perry