An alerter watches for activity at the controls: if the engineer does not touch the throttle, brake, horn or reset button within a set interval, it flashes a light and sounds an alarm, and if the warning is ignored it makes a penalty brake application that stops the train. The interval shortens as speed rises. A dead man's pedal does a cruder version of the same job, applying the brakes whenever the engineer's foot comes off it.
Alerter went off twice while you were on the radio, reset it before it pulls a penalty on us.
Related terms
Big hole
The emergency position of the automatic brake valve, which vents the brake pipe and stops the train as fast as possible.
Set and release
Applying the train's air brakes and then releasing them, the basic sequence of every air brake test.
PTC
Positive train control: an onboard and wayside system that stops a train before it breaks a speed limit or authority.