PTC: What it is, how it works

Los Angeles Metrolink — a 512-mile commuter rail system, which serves the Southern California counties of Los Angeles, Orange, Riverside, San Bernadino and Ventura — is moving to be the first railroad to install and implement a positive train control (PTC) system.

PTC is collision avoidance technology that monitors and controls train movements remotely, can prevent train-to-train collisions, prevent unauthorized train movement into a work zone, halt movement of a train through a switch left in the wrong position, and stop trains exceeding authorized speeds.

Congress has mandated that freight and passenger railroads install PTC on designated lines by Dec. 31, 2015.

To view an animated depiction of how PTC works as a safety overlay system to improve railroad safety, click here.