Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations (2014)

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81 A P P E N D I X B B.1 Introduction A high profile collision between a Los Angeles Metrolink commuter train and a Union Pacific freight train in September 2008 killed 25 people. This incident galvanized political interest in estab- lishing firm deadlines for long-discussed improvements in train control and safety technologies on the nation’s rail system. Interest in the new technologies was focused on lines where passenger trains and/or hazardous materials move on a regular basis. In October 2008 Congress passed the Rail Safety Improvement Act (RSIA), legislation that includes a requirement that much of America’s main line rail network be equipped with advanced signaling and train control technology by December 31, 2015. This package of technologies, known popularly as Positive Train Control (PTC), had been under consideration by carriers and other rail stakeholders for more than two decades but appeared no closer to implementa- tion until the time of the Metrolink disaster. Absent a regulatory mandate the industry had failed, on its own, to develop common design approaches and standards that would support common use across the North American rail network. Other elements of RSIA include revi- sions to hours of service, employee training, safety reporting, and whistleblower protec- tion regulations. It is the implementation of PTC, however, that is seen to have the greatest potential impact on railway capacity over the short to medium term. The Federal Railroad Administration is responsible for promulgation and enforcement of rules applicable to the new systems. B.2 PTC Explained PTC systems are formally defined as “a system designed to prevent collisions between trains, over-speed derailments (derailments caused when a train exceeds speed limits); incursions into established work zone limits (i.e., for roadway workers maintaining track); and the move- ments of a train through an improperly positioned switch.” (Reference: Overview Highlights and Summary of the Rail Safety Improvement Act of 2008, Federal Railroad Administration, March 10, 2009.) The technologies required to support these capabilities are still in various phases of testing and development despite the looming 2015 deadline. Systems can operate through a combination of satellite, ground transponder, and internet communications channels. Securing robust and redundant data transfer capabilities for the huge volumes of information generated by the new PTC architecture is, in and of itself, a major challenge. Figure B-1 is a generic diagram illustrating how a PTC system would work. Discussion of Positive Train Control and Effect on Line Capacity

82 Capacity Modeling Guidebook for Shared-Use Passenger and Freight Rail Operations B.3 Anticipated Effects of PTC on Line Capacity As PTC systems are just evolving, it is premature to quantify the impact of PTC on rail capacity for a typical corridor. However, some general comments of likely effects may be made: • The earliest impacts following PTC installation will be to reduce flexibility and overall cor- ridor capacity. This is because PTC architecture is being employed as an “overlay” to existing, traditional train block and signaling systems. In any given circumstance the more conservative (restrictive) rule will apply for train operations. • Development of PTC data channels will deliver unprecedented volumes of highly granular, near real-time operations data to railway operations and control centers. Extracting manage- ment value from those data streams will require new tools and processes but should, over time, position carriers to refine their operations plans and protocols and improve the predictability and regularity of line operations. • Significant elements of the PTC overlay systems architecture can later serve to support more sophisticated, stand-alone train control systems that move beyond the legacy signaling and con- trol environment. In this new environment the “protection” would be dynamic, that is, it would move along with the train itself. Wayside signals would disappear, and spacing between trains would be the product of both train speeds and the unique deceleration capabilities of each unique train consist. Service capacity benefits may be significant for these new stand-alone sys- tems. The time required for developing and then vetting, through regulation, this entry into the “new world” of rail operations is, however, a matter of considerable controversy. Figure B-1. Generic diagram of a PTC system. Source: “Positive Train Control Implementation Status, Issues, and Impacts”, Federal Railroad Administration, August 2012.