Please forgive the ad but as it's about a hidden side of Glasgow I thought some might like it.
Feel free to move somewhere more relevant if needed.
We've done a 24min ambient soundscaping of a whole circuit of the Glasgow Subway
There's a full explaination of it on our website along with a video review. http://www.psychetecture.com
and you can hear a 128kbps MP3 stream of it on http://psychcomm.bandcamp.com/
Works best on headphones or quite loud on speakers.