I like the idea that this is a class One railroad not only operating passenger stock in the mid 80's, but expanding it and making it better. Thereby being an actual rival to amtrak.
It's definitely evolved as a railroad in terms of an idea. The current incarnation of TPR is the result of a merger in 70's with the Louisville & Nashville RR and the Western Maryland RR.
Those are actually EMD SDP45s! They were part of a lineup of EMD locomotives manufactured in the late 60's, ranging from SDP35, SDP40, and finally SDP45. They were freight locomotives equipped with steam generators for passenger train service. The Southern Pacific bought some units, which featured the cab mounted gyra-light.
As far as I know, there weren't any in real life. The term "theater car" usually applies to inspection cars that carry railroad executives (the ones that have the large glass window taking up the entire rear of the car). However, I do movies were played in some lounge cars; a story I read somewhere talked about a lounge car playing "American Graffiti" on an Amtrak train in the mid-70's. Other than that, the idea of a purpose-built movie theater car is something I kinda dreamed up.