Positive Train Control (PTC) as required under 49 CFR Part 236 Subpart I must be able to automatically stop a train to prevent:

1. Exceeding posted timetable speeds by more than 10 mph
2. Train-to-train collisions, overspeed derailments, unauthorized incursions into work zones, and movements through misaligned switches
3. Any movement when a crew member is outside the cab
4. Departures from terminals without a completed hazmat inspection