How Positive Train Control Works

by @lamthuyvo May 14, 2015 5:00PM ET

Rail experts believe PTC would have prevented Tuesday’s deadly Amtrak derailment.

Topics:
Philadelphia
Pennsylvania
U.S.

Positive Train Control (PTC) is a safety system that monitors train position and speed and feeds the information back to the locomotive in real time, helping engineers stay aware of speed limits and automatically reducing train speed if necessary.

Using GPS satellites and wireless networks, an onboard computer monitors a train's speed and position in real time and sends this information to data centers, where computers also collect train traffic and wireless signals from traffic lights, switches and crossings.