Hi everyone,
That heavyweight is looking very nice! I only have two suggestions, which are to:
1. Darken the interior--especially the walls--a bit. Although the wood paneling may well have been that light shade of beige on the prototype, the car's interior would have been dimly lit compared to the bright sunlight outside; therefore, the interior of the car would have appeared much darker when viewed from outside. It would be cool if you could add a reflection shader to the windows to enhance the effect, but I'm not sure that's really feasible in Railworks, and
2. Darken up the underbody of the car, especially the center sill and components towards the center of the car. No direct light would have ever reached most of the components on the underbody, meaning that the occluded surfaces should appear darker, and the car probably would have picked up a fair bit of grime during its travels, even if the sides were kept clean.
But that's just my

! This project is looking really great and I wish you success as you continue developing your products.
Thanks,
Eliot