I went down there last summer with some friends and we actually ran into some kids who were “working” down there. We started to talk to them and they actaully gave us a “tour” of the subway. There is one area down there that has doors that block it off from the rest or the subway. Its all newer construction so if you been down there then you know what Im talking about. The kids told us that the newspaper used to use that part for storage and delivering mail to comercial buildings. After they abandoned that idea, they cleaned out their area and the doors are left open so you can walk through the subway from one end to the other. I guess its is now a common thing (2-3x per year) for local kids to carry generators down there and set up a rave type party. The kids were telling us that they bring in lights and a DJ and everything is run off of generators.
Not sure how much truth is behind it but it sounds cool. My only concern would be the CO levels with those generators going.