John & Hancock52,
Thanks to both of you for responding to my post. John, your figure painting and other modifications are enviable and I salute you! I am going to take the lazy man's way out and use pre painted figures from GGD, Lionel, Woodland Scenics and Wehonest from the bay . . . I am going to repaint the interiors so they're not all the same monotone tan color.
As long as we are comparing notes about modifying this car, I will add in what I have done so far (see below), which is broadly the same approach of using figures other than the Prieser ones John has used (which I find too difficult to source and I am not into grinding down to fit). I am using Lionel, Railking, WeHonest and some others from "quarter scale" suppliers. All are pre-painted. The Railking figures are the best in terms of variety and they fit without modification.
Hancock52, I did some scheming and measuring today. From what I come up with, the missing long screws for the obs blunt end should be 3mm dia x 60mm long measured from under the screwhead. If these are used however, the existing screw mounting holes in the plastic interior floor will need to be drilled out for clearance to let the screw pass through the floor in order to thread the screw into the roof. Today at my local mom & pop hardware store, I also found some small diameter opaque nylon standoffs/mounting posts that I may use between the floor and the roof for stability. The mounting will be down the road after I paint & populate the interior.
That's very useful to know; I'm obliged. Same here again as regards the fasteners except that I might try fitting mounting tabs to the car body below window height. The long screws or standoffs will definitely show through the car windows although the same arrangement is in all of the Lionel observation cars I have.
The dome observation car is the signature car of this set and the one that I think has the most prototypical interior features, at least at the rear of the car. I was not satisfied with the rest and in particular the dull color so I started by checking what information there is on the car as now in service. I started with the dome, which in the model is nicely built but not as interesting as the real thing:
The seating arrangement with six tables is not replicated in the model and to make something like it all the seats have to be removed, re-spaced and turned:
I then went way overboard in terms of colors, tables, excursion passengers and, er, refreshments, and added floor and overhead lighting in this section because as a display area it's a kind of jewel case but there's no lighting in the dome as it comes from the factory:
This is phase 1 of the interior rebuild; phases 2, 3 and 4 are the section under the dome, the forward section (which has only one window) and the rear. I've mostly done phase 2, which in the UP floor plan copied above is designated a bar area. I stripped out all of the stock seating and partitions, went for a patriotic theme and more LED lighting, in particular in the transparent columns at the corners of the blue bar:
All the beverage details are 3D printed quarter scale stuff.
This is all a lot more elaborate than I intended at the start but as there is reasonably good visibility into this section through the car's side windows I thought, why not? as I had the materials on hand.
I don't anticipate completing phases 3 and 4 until fall/winter.