Since nobody has mentioned Fullerton on the BNSF Transcon, there is cafe right on the depot platform. I think it's still called The Santa Fe Express Cafe. The Old Spaghetti Factory in the former UP Depot in the west end of the parking lot and Knowlwood (awesome burgers!) just to the north of the Spaghetti Factory which also has some tables with track views (of the RR bridge going over Harbor Blvd.) All are casual and tolerate fans well.

I will also concur on the Depot Restaurant in the former Western Pacific Oroville Depot (great steaks) as well as Sarducci's in the San Juan Capistrano Depot (not too much freight action so leaving the radio in the car isn't too difficult). The Old Spaghetti Factory in the former WP depot in Sacramento is also a favorite (even though I'm not much of a pasta fan).

For upscale fine dining, the restaurant at the top of my list is Traxx inside Los Angeles Union Passenger Terminal (Union Station). No trackside view but great ambiance inside the station, outstanding food and a great wine list. My wife and I sometimes ride the train there from somewhere else just to have dinner and a quick train trip. Traxx has never disappointed either of us.

Cheers!