I didn't see that this has been posted on these forums yet. I just heard of it today (via the skyscraperpage forums) and watched it on youtube. It was filmed last summer and it's a behind-the-scenes look at the people who work the 3rd shift and the work they do to maintain the T system. I didn't expect to watch the whole thing but I actually found it all quite interesting.
http://www.youtube.com/watch?v=aPWxs8FVSJM
http://www.youtube.com/watch?v=aPWxs8FVSJM