Friends of the Rail Forum

A very interesting examination of the use of sidings on the London Underground.

A Brief History of Sidings

Whilst reading this link, this lead me via another link to another interesting website which has lots of technical information about London Underground including track and signal diagrams.
http://www.microlp.co.uk/Homea/index.html

Thanks John.

And Steve - your link. A great find. And very interesting.

The more so as the one line I know inside out is the Northern Line and this is what it is all about!