My thinking is basic American comfort food.
For me, a cheeseburger, fries, and pitcher of beer are near perfect. Scrambled eggs, toast. Simple. That kind of thing.
How it relates to railroad traffic is something to explore. In this process there will be surveys, but as the one conceiving of this and a hopeful creative director on behalf of a team, there would be nothing snooty or complicated about it.
There was a chain of restaurants along the railways which featured women staffs and intended to be the 19th century equivalent of “family friendly” I want to say “Gibson Girls” but I thinks that’s wrong.
Cheeseburger and fries are fine choices but I’d hope you expand the menu a bit - perhaps do a search for ‘classic passenger train menus’ for inspiration.
I would be disinclined to choose a food at a restaurant that I could replicate at home with low effort.
I also avoid ordering foods which are difficult to do well in a commercial kitchen. For example fried walleye is fine but I never order salmon - i get it up to near room temp before cooking so the oils don’t congeal into white solids on top. I suspect many restaurants would pull the filet from the fridge and cook it right away out of necessity and wipe the congealed oil off with a kitchen rag.