The California Zephyr has a storied past and this particular engine was traded back to General Electric for credit after a crash in 1972. I wasn't able to verify if the train at DCA was the original--does anyone know for sure?
The California Zephyr was a passenger train known for its domes, which held an additional 24 passengers on a top level. The CZ operated from 1950 to 1970 and traveled from Chicago to San Francisco with stops in Denver and Salt Lake City. It was a two and a half day trip covering over 2,500 miles. At Disney's California Adventure, they have modified a few passenger trains to serve in some new retail capacities.