As far as I know, Lynch, I've been told that it houses the generators for PR, but it seems unlikely since it sits so far from the lift motor and the station itself. My guess is that it's just storage, or something.
When the Laser Loop was around, it sat right on top of that building, which faced the parking lot and Kennywood Blvd., and the second entrance to the park was right next to it. (Anyone else remember when KW had 2 entrances?) Hence why it was painted with the Kennywood logo. I remember walking past the building, and right when they launched the Laser Loop, you would hear this loud roar come from that building.