Hi willy6.
This video:
https://www.youtube.com/watch?v=0a1iHs30gEI
may be useful. It is an Amtrak training video from 1994 and shows the interiors of different Superliner coaches from this period.
For as long as I can remember passenger car interiors from just about every manufacturer have been beige. I guess they figure it is a nice neutral color and most people aren't too concerned about it. People who want them to be accurate will paint the interiors themselves. I'm among the people to whom it doesn't matter.
You can find photos of Superliner Car Interiors on Google.
willy6I have some from Walthers that are somewhat a sand color, but it just didn't look right.
Walthers uses that generic beige in all their lightweight stuff. They do a little better with the heavyweight cars using dark green and brown.
From my experience, if you decide to paint the interior, be sure to wash it very thoroughly. I found out that there is lots of silicone mold release left on them!
Here's a few interior photos:
https://en.wikipedia.org/wiki/Superliner_(railcar)
and some from the '70s!
http://www.usatoday.com/story/travel/2016/03/29/amtrak-1970s/82346702/
and from Amtrak... somethin' special: (one shot of the brown scheme)
http://history.amtrak.com/blogs/blog/creating-somethin-special-a-short-history-of-the-superliners
and if that doesn't get you anywhere, there's always Google...
https://www.google.com/search?q=amtrak+superliner+interior+photos&biw=1344&bih=766&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwi0k4vD28XSAhUK7YMKHRyuBVoQsAQIGQ&dpr=1.25
Good Luck, Ed
When I rode the Empire Builder last June, all the seats were a darker blue, not quite navy. This was true for the coach and the sleeper. I don't recall the dining car seat color.
Modeling whatever I can make out of that stash of kits that takes up half my apartment's spare bedroom.
In the old days, burgundy. In the now, dark blue.
What is the proper seat color of Amtraks Superliners? I have some from Walthers that are somewhat a sand color, but it just didn't look right.