FEDERAL RAILROAD ADMINISTRATION : FREIGHT RAILROADING

Chapter 4
Railroad Research and Development Program

Section 4.6
Train Control
Virtually all train collisions and elements of over speed accidents occurring today are the result of human error—failure to observe or obey wayside signals, or procedural failures by dispatchers, train crews, or maintenance personnel. Positive train control (PTC) systems using digital data communications, automated means of determining train location, and computer control suitable to provide oversight to the human operators of the railroad system, are becoming available at lower costs than traditional signaling systems. This program element is targeted at maintaining a base of technical expertise regarding the application of these sophisticated PTC technologies in order to provide expert advice and consultation to the FRA Office of Safety and to railroads; and to aid in the development and deployment of PTC systems by providing an affordable, uniform, accurate, continuous, reliable, secure, real-time location determination system throughout the United States.

Virtually all train collisions and elements of over speed accidents occurring today are the result of human error—failure to observe or obey wayside signals, or procedural failures by dispatchers, train crews, or maintenance personnel. Positive train control (PTC) systems using digital data communications, automated means of determining train location, and computer control suitable to provide oversight to the human operators of the railroad system, are becoming available at lower costs than traditional signaling systems. This program element is targeted at maintaining a base of technical expertise regarding the application of these sophisticated PTC technologies in order to provide expert advice and consultation to the FRA Office of Safety and to railroads; and to aid in the development and deployment of PTC systems by providing an affordable, uniform, accurate, continuous, reliable, secure, real-time location determination system throughout the United States.

Why a Priority?

The FRA’s 1994 report to Congress, entitled Railroad Communications and Train Control , noted that approximately 20 major accidents per year were result from failures of existing train control methods and procedures. Over the prior 10 years, these accidents resulted in 80 fatalities and more than $500 million in accident costs. More recently, the Railroad Safety Advisory Committee submitted its report, entitled Implementation of Positive Train Control Systems, to the Federal Railroad Administrator in September 1999. The report indicated that the railroad safety record had improved and that such accidents were now resulting in an annual average of seven fatalities, 55 injuries, and $20.6 million in property damage. The report also notes that “the implementation of other pending rule changes and industry actions could play a role in further reducing these numbers. At the same time, traffic and system density are expected to continue to grow, and the extent to which these factors interact has not been clearly resolved.” The NTSB continues to place PTC on its “Most Wanted List” of transportation improvements as it has for the last 13 years, and PTC is listed as a component of the “National Intelligent Transportation Infrastructure” initiative in NSTC’s National Transportation Technology Plan.

PTC is one of the major component elements of Intelligent Railroad Systems described in Chapter 2 of this Plan. The technologies that comprise PTC are the same as those used in air traffic control, maritime vessel tracking systems, and Intelligent Transportation Systems for highways and transit. In addition to providing a greater level of safety and security, PTC systems are also expected to facilitate the ability of railroads to run scheduled operations and provide improved running time, greater running time reliability, higher asset utilization, and greater track capacity. This is important at a time of growing freight and passenger traffic and increasing congestion.

Objectives

This program element is structured to ensure that an adequate base of technical expertise is maintained to support regulatory development enabling advanced train control systems; and to provide guidance in qualifying new and complex operational, communications, software and hardware revisions. The deployment of advanced technology for train control systems presents the railroad industry with opportunities to advance safety while increasing operational efficiencies. Key aspects of advanced train control systems are safety assurance of the complete system, railroad asset tracking ability along with tactical and strategic planners, and communication strategies. Objectives of this program will be:

To apply the state of the art of safety review and assurance for safety-critical systems within the FRA’s regulatory environment.
To deploy the Nationwide Differential Global Positioning System (NDGPS) as a nationwide, uniform, and continuous positioning system, suitable for train control.
To advance the state-of-the-art in tactical and strategic planning and railroad network control systems.

Expected Outcomes

In this program element, FRA engages in four types of activities regarding train control:

Facilitation;
Risk Analysis;
Testing and Evaluation, and
Development of Support Systems.

To facilitate the deployment of PTC on the nation’s railroads, FRA is taking a lead role within USDOT as the sponsoring agency for Nationwide Differential GPS. FRA is undertaking the analyses to evaluate the risks of collisions and over speed accidents on the corridors that make up the national railroad network, as well as to evaluate the risks of the various technologies that comprise PTC. FRA will undertake the necessary testing and evaluation to confirm the integrity of the various PTC demonstration programs when they become operational, and will establish facilities where further testing and evaluation can be carried out. Finally, Congress directed FRA to initiate the development of tactical traffic planners, one of the key support systems for PTC, needed to obtain the business benefits. FRA proposes to expand that activity into the development of strategic traffic planners as well.

Expected outcomes will include a better understanding of new advanced train control and dispatching systems and technologies; location and tracking systems; new methods of monitoring and control of operationally related railroad assets; such as switches, and remote gathering of right-of-way integrity information. Outcomes will be geared towards the safety issues of such new technologies, when applied in the railroad industry; and when warranted, demonstrations of the new technologies to validate potential risk reduction or mitigation benefits.

The PTC demonstration projects, a key element of FRA’s overall program of train control activities, are described in Chapter 5 of this Plan.

Project Descriptions

NATIONWIDE DIFFERENTIAL GPS

Nationwide Differential GPS (NDGPS) is described in Chapter 2 as an element of Intelligent Railroad Systems. NDGPS is a joint project of the FRA, the U.S. Coast Guard, the Federal Highway Administration, and the Office of the Secretary of Transportation; and is now being implemented as an expansion of the Coast Guard’s Maritime DGPS network. By the end of 2001, approximately 80 percent of the area of the contiguous 48 states will be able to receive an NDGPS correction signal from at least one NDGPS transmitting site. By the end of 2004 all the territory of the contiguous 48 states will receive the signal from at least two transmitting sites.

In July 1999, FRA published a report to Congress, entitled The Department of Transportation on Civilian Use of the Global Positioning System (GPS): The Nationwide Differential Global Positioning System and Additional Civilian GPS Signals . It states that FRA established the Federal requirement for NDGPS because of its need for a location determination system for the PTC safety initiative. It also noted that NDGPS would also play a role in the national Intelligent Transportation System program by helping to improve the effectiveness and efficiency of its services. Full nationwide deployment of NDGPS would significantly aid the development and deployment of PTC systems by providing an affordable, uniform, continuous, accurate, reliable, msecure, real-time location determination system throughout the United States. NDGPS provides a GPS integrity monitoring capability; it gives an alarm to users within 5 seconds of detecting a fault with the signal from any GPS satellite.

Figure 4.6.1 GWEN Site Converted to NDGPS, Appleton, Washington

Public Law 105-66, Section 346 (October 1997) authorized the Secretary of Transportation to establish, operate, and manage NDGPS to promote public safety. Congress subsequently appropriated funds to the Coast Guard in FY1998 authorizing them to take possession of decommissioned Ground Wave Emergency Network (GWEN) sites from the Air Force, and directed them to begin implementation of the NDGPS. Neither the capabilities of, nor the need for, NDGPS for railroad train control purposes were altered by the elimination of Selective Availability (the intentional degradation of the signal) from the GPS Standard Positioning Service by Presidential directive on May 1, 2000.

When completed, the NDGPS network will number 86 transmitting sites (including 15 in Alaska) and NDGPS Master Control Stations in Alexandria, Virginia, and Petaluma, California. By the end of 2001, 23 of these transmitting sites are to be operational. The new sites are being integrated into the Continuously Operating Reference Station and Precipitable Water Vapor System networks operated by the U.S. Department of Commerce.

Figure 4.6.2 NDGPS Coverage – End of 2001

The installation and implementation of NDGPS across the continental United States and Alaska, is described in detail in the 1999 Federal Radionavigation Plan. It is another component of the National Science and Technology Council’s “National Intelligent Transportation Infrastructure” initiative; and is a key element in supporting the Strategic Goals of the U.S. Department of Transportation Strategic Plan 2000-2005 to improve safety, mobility, economic growth and trade, human and natural environment, and national security. NDGPS will help reduce transportation collisions and fatalities, reduce travel and shipping times, increase overall transportation system throughput, and reduce transportation operating costs. The integrity and positioning information from NDGPS will also be very valuable to those who are engaged in strengthening the security of the nation’s surface transportation modes in the aftermath of the recent terrorist activity.

POSITIVE TRAIN CONTROL ANALYSES

Corridor Risk Assessment

Projects to identify which, if any, railroad corridors might benefit from PTC on more than an average basis are nearing completion with development of the geographical information system and accident location databases and the model specification for accident prediction, definition of comparison groups, and consequence estimation. Included is development of a risk identification model that uses the FRA’s railroad network GIS platform, coupled with other relevant data such as passenger and freight (including hazmat) traffic patterns, detailed track and signal system configurations, population densities along the line, and the specific accident locations.

Risks of Signal and Train Control Devices

The objective of this program is to develop methods to mitigate potential hazardous failures in the signal systems that are in common use today. Technological advances, particularly in the application of embedded microprocessors and high-power electronics, have resulted in many wayside and train-borne systems having interfaces among signal, train control, communications, and power control functions. One element of this project is to explore more reliable methods to detect train presence. This is of vital importance to the overall safety of a train control system and for preventing collisions at highway-rail crossings.

This project will investigate attributes of microprocessor-based and other advanced signal and train-control systems. It is designed to evaluate current regulations governing such systems, and provide guidelines for development of new regulatory language or other viable regulatory or auditing alternatives to ensure minimal requirements that would guarantee the level of safety of these systems to be the same or better than more conventional systems.

Work will lead to guidelines and recommended practices for safety validation of software-driven and other advanced technology train control systems. The safety-relevant implications of latent faults in electrical and electronic systems affecting train propulsion and control require procedures for testing and validating the safety of these new systems. Research in this area needs to be conducted from a systems perspective. Of particular importance is ensuring the electromagnetic compatibility among all interrelated systems, so that neither causes ill effects upon each other.

Human Reliability Analysis in PTC

The reliability of complex systems is now a routinely analyzed aspect of systems engineering. However, while reliability analyses have been routinely performed on electrical, mechanical and chemical systems for many years, it has only recently been recognized that to minimize the probability of system failure, human reliability must also be considered. This project, also described in Section 4.2 of this Plan, will, in consultation with the Office of Safety and the Railroad Safety Advisory Committee (RSAC) on PTC, determine the critical human failure modes in emerging PTC technologies and quantify the human failure probabilities. This project is currently examining the Communications-Based Train Management system of CSX and is expected to continue into FY 2005.

TESTING AND EVALUATION OF POSITIVE TRAIN CONTROL SYSTEMS

As various train control concepts are installed and tested around the country, FRA proposes to participate in their testing and evaluation. An example of such participation is FRA’s involvement in varying degrees in the ongoing PTC demonstration projects in Michigan, Alaska, South Carolina, and Illinois. The dynamic performance of the systems will be tested to confirm braking curves, headways, and improvements in meets and passes. Handling of the highway-rail intersections will receive special attention. The evaluations will include reviews of the safety documentation provided by the system developers and an assessment to determine if actual operation in the field is consistent with that described in the documentation. Verification of the “robustness” and “fault tolerance” of the new systems will be determined.

FRA is installing a Vehicle Tracking System at the TTC with three objectives in mind: (1) improve the safety of operations at TTC; (2) improve the efficiency of operations at TTC; and (3) provide a testbed at TTC for testing and validating various PTC architectures and components. The project includes the installation of a digital communications network at the TTC. It also includes equipping locomotives; track maintenance and inspection equipment; and road vehicles with GPS/DGPS receivers, data radios, and display screens to permit transmission of location and velocity information to the TTC’s Operations Center and to receive instructions and information messages. A demonstration system that tracks three vehicles is currently operational, and the full system is planned for completion in FY 2002.

TACTICAL AND STRATEGIC TRAFFIC PLANNERS

Tactical and strategic planners are described in Chapter 2 , Intelligent Railroad Systems. Congress, recognizing that there is growing traffic congestion in high density corridors that has resulted from recent consolidations in the rail industry, directed FRA to undertake the development and deployment of such systems to enable railroads to manage the flow of rail traffic and avoid congestion and jamming. In FY 1999 - 2000, Congress earmarked funds for the development of algorithms for a tactical traffic planner to optimize meet-pass planning, along with building the interfaces with computer-aided dispatching systems.

To optimize the running time, capacity, and asset utilization benefits from tactical and strategic traffic planners, the planners should be installed along with PTC systems that can provide the precise train location and speed information so that the TTP and STP have a timely and accurate view of operations and can plan most effectively. The PTC systems then provide the capability to implement the optimum plans by transmitting operating authorities and precise speed control instructions back to trains.

In FY 2003 and 2004, FRA proposes that work on tactical and strategic traffic planners be carried out in such a manner that they can interact with, and be demonstrated with, one or more of the PTC demonstration projects described in Chapter 5 . The project should be competed among interested suppliers, and cost sharing would be one of the selection criteria.

Table 4.6
Planned Timeline for Train Control Projects