I have the operating passenger platform. It has the same footprint as the regular platforms, like the two extra's that come with the big MTH passenger terminal. I use the accessory switch that comes with it and have it mounted underneath the table in front of the platform. Close to the edge so i can flip it while the train is stopped in front. Wiring is pretty straight forward in the directions, I chose to have the wire that controls the lights hooked up to a seperate wire so that it lights up when all the other lights are turned on at the control panel.
It comes with detailed instructions on how to wire it up to an ITAD.Heres a quick vid of it in operation someone posted on youtube ; (I'm a 3-rail guy, but I just love that S scale PRR train )