The alerter helps crew members maintain vigilance in the locomotive cab by monitoring locomotive engineer activity. If it has been too long since the locomotive engineer performed an input or action to reset the alerter, the system issues visual and audible alerts, and applies train brakes if there are still no inputs from the crew. However, the agency found, an alerter’s reckoning of “idle time” can be reset to zero by inputs that do not necessarily demonstrate a crew member’s continuing engagement.