You could very easily keep these old trains useable. Just replace the coal-fired boilers with one that run on petrol/diesel/fuel oil or use an electric boiler 9like a water heater). Then you have the function and looks, with less pollution.
I rode Union Pacific's Challenger from Chicago to Pocatello, Idaho, in 1952 at the age of seven. We hooked up to a Big Boy in Cheyenne for the haul up Sherman Hill, and I wondered why a steam engine should pull a state-of-the-art streamliner. Growing up in Poky thereafter, I remember row upon row of steam engines parked along Yellowstone Avenue into downtown for years as they were scrapped. Later, in high school, I would occasionally spend time high up in Juniper Hills at a buddy's house (his dad was a UP supervisor) listening to jazz and watching the yellow streamliners worm their way through the Portneuf Gap and into the yard (then the largest between Omaha and Portland, and still very active). An indelible memory.