Thanks for all your feedback (I gave both of you "Likes," UP4000 and MrTilt)! Since the APT-E never entered revenue service, I'm not gonna worry about being uber realistic. Like I said, I've left one train true to the prototype, and I want to run the 2nd train as a real passenger train and I just want to add several more coaches and not use the computer car; i.e. the consist will be: PC-1, a bunch of TC-1 coaches, and PC-2. Since TC-2 is the computer car, I'll not be running it on the 2nd train.
Look back through this thread? Uhm, you do realise this thread is 171 pages long, eh?
Do i plan on adding coach seats to the interiors of the TC-1s? No. Since this is such a rare and expensive train, I don't plan to make any destructive modifications to them or even weather them. I'm impressed at the detail that Rapido put into these trains as they are!
Get rid of the tilt mechanism to make the model more authentic? No. I'm not gonna try to remove, modify, or disable the tilt mechanism (I wouldn't even know how to begin to do that -- you're a braver man than I to even plan to make such changes to your train).
Though I am tempted to take one of my extra TC-1 coaches and turn it into a cafe or dining car by removing a window or two (if only I could match that blue paint exactly). And I also saw a video where someone installed a disco lighting system in an APT-E coach, lol.
One of these days, I'd love to go to the NRM and learn more about the history of this train, though that picture book that came with my 2 trains was fascinating to read!