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North American Joint Positive Train Control (NAJPTC)

On January 23, 1998, the Federal Railroad Administration (FRA) joined the Association of American Railroads (AAR) and the Illinois Department of Transportation (IDOT) to initiate development of a high-speed Positive Train Control (PTC) project for the St. Louis-Chicago corridor. Concurrent and subsequent railroad industry efforts directed toward advancing PTC technology development were subsequently integrated into the North American Joint Positive Train Control (NAJPTC) Program. This project is the primary venue and means for the establishment of PTC interoperability standards (i.e., the ability of a train to successfully transition from one railroad or type of train control system onto another seamlessly, at track speed, while under continuous supervision of the train control systems). Over many years, AAR, IDOT, and FRA’s Next Generation High-Speed Rail Program (NGHSR) shared the project costs associated with these activities.

The Transportation Technology Center, Inc. (TTCI), a facility owned by the FRA and a subsidiary of the AAR, was contracted as the lead organization to develop the specifications and a Request for Proposal (RFP) with Aeronautical Radio, Inc. (ARINC) as the System Engineer. TTCI was also the project manager of the cooperative NAJPTC Program. The sponsors also awarded a contract to Lockheed Martin Corporation in June 2000 to serve as the System Developer/Integrator for the development of a PTC system specification for the St. Louis-Chicago corridor.

Lockheed Martin set up a system integration laboratory in their Mitchel Field facility in Mitchel Field, NY. The components were tested as an integrated system in the laboratory for debugging and functional enhancement prior to the commencement of field testing. Several field trials were conducted in 2005 on the St. Louis-Chicago corridor allowing its architects and designers to undertake trouble-shooting and debugging. The initial trials were followed by “shadow” testing in 2006 using several locomotives entrained in existing passenger revenue service, which operated the PTC system in the background without the brake enforcement functions. This enabled the developer to monitor the system on a daily basis, and was expected to accelerate the development effort.

Testing done in the Lockheed Martin Laboratory and in the field, revealed that a significant amount of additional software development and enhancement was required for the PTC system to be compatible with the existing operating environment in which there are regular revenue services. It was also determined that the communication network required a throughput capacity upgrade for the PTC system to function properly in that environment. It also became obvious that several additional years of applied development efforts were needed to overcome these difficulties. The NAJPTC stakeholders (FRA, AAR and IDOT) jointly decided that additional research and development would be best performed in a controlled environment, like that at TTCI. As a result, IDOT withdrew from the partnership and chose to employ a conventional cab signal system for its revenue services on the corridor in order to fulfill the requirements of their high-speed intercity passenger transportation initiative.

In January 2007, a new vital PTC development program was initiated to build upon the previous successes of the NAJPTC program at TTCI with funding from FRA through the Railroad Research Foundation, a non-profit subsidiary of the AAR. Lockheed Martin committed in-kind contributions to this effort as well.

A three year schedule was established for these continuing efforts to develop a vital PTC system for use in non-signaled territory. After that time, the program will be evaluated to determined whether further enhancements such as adding additional types of territory, moving block implementation, and virtual signaling systems, are necessary and viable. Funding for this program is also being used to improve PTC technology components, such as a new on-board braking algorithm capability and an alternate enforcement scheme, which will benefit all PTC developments.

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