Dead Man's Switch - Trains Magazine

Sawtooth500

So what do new units have?

ANSWER:  Alerters.  Depending on the design of the device, the engineer has to "do something" like change throttle settings, blow the horn, ring the engine bell, work the sanders, dim the headlight, or acknowledge a cab signal change.  More often though he presses an acknowledgement device.

Every 90-seconds or so, the Alerter "will ask" for an acknowledgement.  The request is usually visual at first, but then a visual signal accompanied by a chirping alarm comes next. 

QUESTION:  "What happens if you don't push the button?" 

ANSWER:  If the engineer takes too long to acknowledge the Alerter, the system takes over by automatically initiating a brake application, throttling the locomotive down, and bringing the train to a grinding halt.  After the train stops, the engineer can recover control and get the train going again.

A more affective system might replace the chirping tone with a random stream of 250 or so pre-recorded insults directed at the crew and delivered by "Mr. Warmth" himself, comedian Don Rickles.