The communications system architecture of the North American Advanced Train Control System

The Advanced Train Control System (ATCS) communications system, which provides for the information flow in the North American ATCS, is presented in the context of the overall ATCS plan. The major components and basic operation of ATCS are described. The features, functions, and connectivity of the nodes in the communication system are defined. The communications system is based on the OSI (Open Systems Interconnection) model; and the protocols used are described with particular emphasis on the radio data link. Special features of the communications system, including a description of how vehicles are tracked, are included.<
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