Who was the first manufacturer to introduce a breakdown unit. By that, I mean a train car or loco that can go around the track as part of a consist, but also has a feature where it can activate a breakdown sequence. Perhaps crew chatter discussing a malfunctioning engine, or maybe even smoke coming out where it shouldn't. I know Lionel made a breakdown F3 B unit. Any others?
Was this introduced in O gauge, or maybe the HO guys had it first?
Just wondering...