Abstract: The ability to precisely locate and track train movements is essential for safety and efficient modern train operations. The train tracking system must be able to accurately and reliably locate both ends of the train and provide accurate train length at initialization and during train operation. In addition, the accuracy must be at a level precise enough to resolve which track the train is on in a multi-track location. Current Positive Train Control (PTC) implementation relies on GPS determination of Head Of Train (HOT) location with GPS positioning accuracy being 15 meters at 95% confidence level. And the End Of Train (EOT) location is derived from the GPS position of HOT, crew-entered train length, and known switch position. The lack of GPS accuracy and the error prone manual entry of track selection and estimated train length at initialization, limits safety benefits, operation efficiency, and line capacity. Few examples of these limitations range from uncertain track discrimination, uncertain automatic release of authority behind the train in dark territory, reduced rear-of-train protection when shunting cars, reduced line capacity due to longer than necessary protection buffer between trains. These and other limitations became the motivation for the Positive Train Location (PTL) research. PTL research was launched in two phases to meet or exceed key performance requirements in all environments (with and without GPS). Mr. Alibrahim will outline the PTL research requirements, testing and validation criteria, and test results in some details for phase I Proof of Concept (PoC) and Phase II commercial ready system. PTL research continues to develop the Next Generation HOT/EOT (NGHE) to improve performance and enable modern train operations like Virtual Block, Moving Block, and automated train operation.
