Positive Train Control (PTC): The Need of an Hour for US Railroads

By Pranav Misal

Industry Trends

Amtrak Cascades train 501, on its inaugural journey, traveling from Seattle to Portland derailed on Dec. 18 near Tacoma while navigating a curve. Data obtained from trailing locomotive suggests that Amtrak was operating at a speed of 80mph on a track segment with a speed restriction of 30mph. The train was powered by Siemens Diesel Charger Locomotive in the front and GE P42 Genesis Locomotive from the rear end of the Talgo passenger cars. Based on the preliminary investigation by the rail officials, the emergency brakes were deployed automatically but were not manually activated by the engineer and positive train control (PTC) -- a technology that automatically slows down and stops a speeding train had been installed on the right-of-way, but it was neither operational nor activated at the time of journey.

With this incident, it brings the focus back to the mandate enforced by Federal Railroad Association on the installation of PTC on US Railroads. The original (unfunded) mandate stipulated conformance by the end of 2015, but the slow rate of implementation resulted in pushing the due date to December 2018. Also, in 2012 the Federal Railway Administration modified the mandate to eliminate the need for implementation on lines that don’t carry passengers or toxic materials.

What is Positive Train Control? What does it do? How does it help?

Positive train control refers to systems designed to meet the mandate outlined in the US Rail Safety Improvement Act of 2008. Safety is the primary objective of a PTC system, which is intended to provide train separation and prevent train-to-train collisions, over-speed derailments, and incursions into roadway work limits that could jeopardize rail worker safety.

PTC works by slowing and stopping trains that are cruising over posted speed limits--that technology might have helped prevent anPositive Train Control (Flickr) incident. The systems can be added to existing lines. The implementation also allows trains to go faster due to improvements in communication, train management, and operational efficiency. PTC is designed to prevent accidents like the Amtrak crash in Seattle and Philadelphia.

PTC system components include onboard computers, wayside interface units, ground & wireless communication, office servers, etc. Train’s onboard computer stores all the required data (speed limits, constructions, hazards). During the journey, the onboard computer communicates with the dispatchers and wayside signals. PTC operates by sending and receiving a continuous stream of wireless signals about train location, speed, and direction. PTC systems utilize advanced technologies including digital radio links, global positioning systems, and wayside computer control systems that help dispatchers and train crews safely managing train movements.

What is holding back the installation and activation of Positive Train Control?

Interoperability: Creating a system that is completely interoperable with PTC is a challenge. It means that PTC must work for any train on any track and should be compatible with other railroads with different PTC systems.

Testing and Upgrades: PTC requires substantial upgrades to the four main segments of rail operations: the server, locomotives, wayside signals, and communications components. Each element must undergo rigorous testing before it can be deployed. The limited number of suppliers that provide technical design services, particularly for signal systems, is hampering the quick installation of PTC technology.

Bulk Deployment: PTC involves the deployment of several technologies pieces which makes it complicated to execute and integrate the system.

Expensive and Time Intensive: PTC is both expensive and time-intensive to install. Not only must every locomotive operating on a PTC route have the necessary hardware in place, but equipment also needs to be stationed at key locations along the line.

These tragic events highlight not only the urgent need for Positive Train Control measures but also the extreme difficulty the rail industry is facing making those technologies a reality.

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