At its heart, Positive Train Control is all about safety.
Positive Train Control, or PTC, is a collection of federally regulated requirements that are being installed on trains and railroads across the United States. PTC involves taking existing rail side and on-board equipment, and synchronizing them with new technologies to create a safer experience for passengers and rail crews as mandated by the U.S Rail Safety Improvement Act of 2008.
There are three key elements to the PTC system: wayside devices, a dispatch center, and the locomotive itself.
The wayside device is essentially a trackside stoplight — with green, yellow and red lights — that appears every two miles, segmenting the tracks into two-mile “blocks.” If the light is green, it means that there are no other trains in the two blocks ahead and it is safe to proceed. If the light is yellow, then there is a train in the block that is two ahead of yours. If the light is red, then there is a train in the next block. Operators aboard the locomotive use these signals to dictate the proceedings of the train.
Under PTC, these signals, as well as train location, will be tracked through a series of communications networks, and then sent to a dispatch system back at the railroad’s control center, which is much like an air traffic control center. The dispatcher at the control center will know what the signals say, and thanks to on-board GPS technology will be able to gather the location of all locomotives on the railways, as well as how fast they are going.
Using GPS, PTC will create a rolling buffer zone ahead of trains. If for some reason the train does not adhere to the signals and starts to penetrate that buffer zone, the computer will take over and bring the train safely to a stop before there is any type of incident on the track. So even in the case of operator error, technology will be in place to dramatically decrease the risk of collision. The end result: a higher level of safety for the nearly 30 million people who ride the rails in the US each year.
Overall, PTC requires the updating of 17,000 locomotives and 75,000 wayside devices — that’s an average of 9 locomotives and 38 wayside devices per day before the December 31, 2015 deadline. Between the major Class I Railroads — BNSF Railway, Canadian National Railway, Canadian Pacific Railway, CSX Transportation, Kansas City Southern Railway, Norfolk Southern Railway and Union Pacific Railroad — industry-wide costs are expected to reach $5 billion.