It’s not just London with a whole host of abandoned rail infrastructure. The Petite Ceinture (or The Little Belt) was built in 1852 and was Paris’ version of The Circle Line connecting the cities main line termini. The 20 mile line was eventually closed when competition from The Paris Metro made it obsolete. It is now a facilitating hidden space within the city, and is being documented by Thomas Jorion.
Another great little insight into the line is featured here by from the BBC
Image by J.M. Schomburg
Calling All Stations 
This is a great story, saw it on BBC website recently. on seeing the old footage of the stations and rolling stock I immediately thought it would make a great scratch modelling project. Then I realised I already have at least another 20 projects still to complete! Can’t wait for retirement!