Reducing the probability of collisions between trains, collisions between trains and maintenance-of-way crews and overspeed accidents are top priorities for any rail operation. The Illinois Department of Transportation (IDOT), in conjunction with the Federal Railroad Administration (FRA) and Association of American Railroads (AAR), is working on a way to make those incidents more preventable with its positive train control (PTC) project.
The project entails installing a PTC system on a 120-mile segment of a mixed passenger/freight line of the Union Pacific Railroad extending between Springfield and Mazonia, Ill. The line segment is part of a high-speed rail corridor designated by IDOT and the FRA between Chicago and St. Louis.
“The primary benefit is increased railway safety,” says Alan Polivka, general manager of the North American Joint Positive Train Control Program, which the IDOT project is part of. “The project is going very well, with great momentum.”
On half of the segment, the system is being integrated with the existing railroad traffic control and signaling system. There, the system operates in fixed block mode. Existing signals allow for speeds of up to 79 mph; the PTC system allows for speeds of above 79 mph. The system is being designed so that the authority conveyed by the onboard display is constrained by the wayside signal system in this half of the segment.
The other half of the segment uses the PTC as a stand-alone system with moving block operation. It can provide conventional fixed block operation for trains not equipped with PTC onboard functionality, or for which digital data radio communications have been lost. These non-communicating trains will be tracked by track block occupancy status to the office via the data communications network.
PTC involves the application of digital data communications, automatic positioning systems, wayside interface units, onboard and control center computers and other advanced technologies. The IDOT project is now halfway through its 30-month development that will be complete at the end of 2002, with revenue operation slated for 2003. The design is being implemented in multiple phases, with each phase adding functions that could stand alone. The primary use for this type of system is on high-speed passenger lines and freight lines, though other types of rail operations can use it.
Two keys to the performance of the system are: the ability to locate and monitor movement of trains with precision and the ability of the operators to safely and effectively use the system. Both are being done within the project’s objectives of being cost-effective. For each part of the system built, extensive testing is done before being deployed on the IDOT corridor. Field testing of each build is also performed.
The IDOT PTC territory contains 133 crossings — 103 public road crossings, 10 pedestrian crossings and 20 private at-grade crossings. Of those, 94 are equipped with automatic warning systems and many were upgraded to use constant time warning equipment. As part of the project, 74 crossings will be upgraded with advanced activation capabilities to provide for high-speed passenger operation.
The system developer/integrator for the IDOT project is a team led by Lockheed Martin Corp. and includes Wabtec Railway Electronics, Union Switch & Signal Inc. and Parsons Brinckerhoff Transit & Rail Systems Inc. The prime contractor for the project is the Transportation Technology Center Inc.
Goals of IDOT project
The IDOT PTC system will function as a safety-critical train control system independently and in conjunction with the existing Union Pacific CTC system used to control the territory. Several things imperative to the project are:
1. Displaying operating information to rail crews. The IDOT PTC system will continuously display train location, limits of authority, actual train speed, maximum authorized speed and bulletin information.
2. Warning train crews of potential violations. The system will warn of approach to authority limits or reduction in authorized speed.
3. Open standards. The system is being designed to conform with or set new open industry standards, allowing interoperability of trains among different railroads and cost-effective availability of products from multiple vendors.
4. Demonstrate moving block operation. The system will provide moving block operations in PTC stand-alone territory, allowing communicating trains authority to the rear of preceding communicating trains rather than to fixed block limits.
5. Integrating speed limits and restrictions. The system will integrate temporary and permanent restrictions on train movement to determine the most restrictive operation allowed.
Other PTC projects
The IDOT project is part of the North American Joint Positive Train Control Program (NAJPTC), a five-year, $60 million effort sponsored and funded by the AAR, the FRA and IDOT. The purpose of the program is to develop standards for PTC system components to promote industry interoperability.
The NAJPTC consists of three inter-related projects: the IDOT PTC Project, the Eastern PTC Project and the Industry Train Control Standards Project. The projects provide input to and accept outputs from each other as they work toward interoperability.
The Industry Train Control Standards Project is developing industry-wide train control standards for cost-effective, interoperable train control and related systems and devices. The project published standards, including the Train Control Standards Data Dictionary that provides a common, core set of data elements to be used in the development of a standard system.
The Eastern PTC Project has defined an interoperable onboard platform and is developing a standard approach for integrating it with various types of train control territories. This project already presented an onboard platform prototype and is now working on integrating that with existing wayside train control systems.