Santa Fe #3751 steam locomotive.
Santa Fe 3751 (Los Angeles-San Bernardino) Feat. High Speed Pace! - YouTube
Santa Fe 3751 (Los Angeles-San Bernardino) Feat. High Speed Pace! - YouTube
Very clean, thought for a minute that the fuel might have been propane instead of coal or wood but then saw smoke emerge from the stack! Ah, "Those Good Old Days" gone by. Oh Yes, I Know, never seen one powered by propane.
The lack of discernible smoke was very impressive. .