Anon_e_mouse Jr. and I enjoyed ourselves trememdously - thanks to everyone who organized it, and especially to those who set up the rope! Now, as Paul Harvey says, here's "the rest of the story".
After the tour ended, we went to lunch and eventually found ourselves southbound on the 6, headed for 23rd Street. (I recently acquired an old post card of the station and I wanted to see how much was recognizable. The answer: not much.) While looking around the southbound platform, we observed a faded sign, black with silver or white letters, attached to the column wall between the local and express tracks. I didn't write down the full text - it had something to do with it being dangerous to cross the tracks - but it was signed "Interborough Rapid Transit Co." I did photograph it; when I finish the roll we'll see if it came out. Since I was using Kodachrome 64 in my point-and-shoot it is a flash shot, and it's not too close, so Kevin, if you're reading this, grab your good camera and get a good shot!
Until next time...
Anon_e_mouse