Until I realized the original post is 6+ months old, I was going to mention that in all the exictement, one of the styrofoam sheets on the 5th car was still attached between the truck and the floor! Presumably long since removed now. I wonder if the adult beverage had anything to do with that? .
An 18" SP sound car would be sweet! I don't have this set, but I do have the one (4 car + 2 Add-on) that was cataloged to go with the PA-1's probably 5-6 years ago. They never (to the best of my knowledge - I was sure looking out for one!) made a sound car to go with that set, so I 'm sure that doesn't help the scarcity of the one shown.
-Dave