runaway train
noun1
Rail transport, Railways, Transport An uncontrolled railroad incident where a train or rolling stock moves without operator control, often due to brake failure, loss of power, or an accidental release on the main line.
- Lefty comes to the rescue by descending from an aeroplane on to the runaway train, which he saves from destruction, and administers a thrashing to the doctor.1926, “Reviews Of New Productions”, in The Film Renter and Moving Picture News, numbers 635-643, page 44: