Role of Positive Train Control in Rail Safety

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Under the Rail Safety Improvement Act, all freight and commuter railroads in the United States are to be equipped with Positive Train Control (PTC) systems by the end of 2015. This decision was taken by Congress in 2008 and is intended to improve safety of rail transport by reducing the risk of human error. It is expected that these measures will contribute to the prevention of train-to-train collisions, over-speed derailments, train movement through a switch left, and to the protection of roadway workers and their equipment.

What is PTC?

PTC is a rail safety technology designed to automatically stop or slow a train before certain types of accidents occur. It integrates multiple technologies, including global positioning system (GPS), on-board computers and digital communications to monitor and control trains.

The infrastructure of the PTC system typically comprises five core segments:

  • Back Office
  • Communications
  • Locomotive
  • Wayside
  • Maintenance of Way

How does PTC work?

With PTC, the system determines the areas where the train needs to be slowed or stopped, and communicates with the train’s onboard computer in order to send this information to a train operator. It not only warns the operator, but also displays the train’s safe braking distance based on the train’s speed, length, width, weight, and the grade and curvature of the track. If the operator does not respond to the warning and screen display, the onboard computer activates the brakes and safely stops the train.

What are the difficulties of PTC implementation?

With just six months left until deadline, many rail operators face a number of challenges in implementing PTC, high cost being the primary of them. Thus, it is possible that the 2015 deadline may yet be extended to 2020.


We at PSA have actual experiences in the development and implementation of Positive Train Control systems. The most recent development project in this area is aimed at creating a railroad monitoring system – a part of PTC, responsible for displaying events, alarms, logs, corrective actions, and other information that is site specific, and then making the information available on a web interface.

If you need any additional information on the topic or you have any questions on your rail project, please don’t hesitate to email us at contactus@psa-software.com.


1. http://www.railwaysignalling.eu/positive-train-control

2. http://www.metrolinktrains.com/agency/page/title/ptc

PSA Marketing Team

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