A recent trip through the 'Nati got me thinking about the subway again, and I remembered they used to do occasional tours.
Not anymore, according to this site:
http://www.cincymu.../programs/heritage (about halfway down the page). I'm genuinely disappointed, as I figure that's going to be about the only way in anymore. Being that I'm an out of towner, I know I have a slim chance of striking it lucky and the subway being accessible during the random visits we make down there.
I'm not completely giving up, but this is a bummer, as the subway is high on my UE bucket list.