Ha! One search effort and I did learn the abandoned train is in the Ural Region, Russia.
Part of a Cold War backup plan by the Soviets, that was fortunately never required.
Trainspotting in the Shumkovo railway cemetery
Watch: Rare abandoned trains from the early 20th century reached their terminus near the Russian village of Shumkovo
www.euronews.com
The Steam Train Graveyard: Used to be a secret location should war break out - Abandoned Spaces
www.abandonedspaces.com