Metrolink launched Positive Train Control (PTC) in trains with passengers on board, across the entire 341-mile network the agency owns earlier this month. With this latest accomplishment, Metrolink becomes the first railroad in the nation to have PTC running during regular service on all of its hosted lines and remains on track to become the nation's first passenger rail system to have a fully operational, interoperable, and certified PTC system in place. Metrolink began operating PTC on the last of Metrolink's hosted rail system on June 14. PTC involves a Global Positioning System (GPS)-based technology capable of preventing train-to-train collisions, over-speed derailments, unauthorized incursion into work zones and train movement through switches left in the wrong position. PTC monitors and, if necessary, controls train movement in the event of human error. The current cost for developing, installing and deploying PTC on the Metrolink system is $216.4 million.