Passenger carriage — story beat: The train jolted to a stop in open country. Lights flicker, nobody is panicking yet, but the conductor has not walked through for a long time, and the doors will not open. Something stopped this train on purpose, or by accident — and you are the only railway worker aboard.
Conductor's cabin — story beat: His tea is still warm. His cap is not here — it was in the carriage — but his logbook is missing from its shelf, and the last radio entry is unfinished. He left in a hurry, toward the engine, and he never came back. You are now following his last steps.
Engine cab — story beat: Here is the answer to where he went: a burst steam valve drove him back, the emergency brake locked, and the door jammed behind him. He is alive, dazed, and relieved to see another railway worker. Now the train is yours to restart — if you can put power, brakes and fire back in the right order.
Train status: stopped — power off, brakes locked, boiler cold.