Which system monitors train movements and enforces safety rules to prevent collisions or overspeed?

• A. Positive Train Control (PTC)
• B. Automatic Train Protection (ATP)
• C. Automatic Train Operation (ATO)
• D. Catenary system

Answer: (A)

A system that constantly tracks a train’s position and authority and can automatically intervene to prevent unsafe conditions is the core idea. Positive Train Control does exactly that: it combines data from track layouts, signaling, onboard position, and wireless communications to determine the allowed speed and movement for each train. If a train would exceed the speed limit, pass a signal at danger, or enter a space where another train has priority, the system can automatically apply the brakes or limit acceleration to bring the train to a safe state. This automatic safety intervention is what prevents collisions and overspeed, going beyond what a human operator could reliably achieve in time.

Automatic Train Protection is a related safety concept used in some regions, but the scenario described points to the modern, comprehensive control system commonly referred to in this context. Automatic Train Operation focuses on driving the train automatically for efficiency and service patterns rather than enforcing fixed safety rules, and a catenary system is merely the overhead power supply, not a safety or movement-monitoring system.