BLOOMINGDALE, ILTechnology exists to design a system that can start applying a train's brakes if an engineer fails to obey stop signals. Positive Train Control (PTC), a system that monitors railroads through a wireless network, can help to prevent train crashes and enhance railroad safety. Currently used in several pilot programs, PTC systems will be required under the federal Railroad Safety Improvement Act (RSIA). Antennas are a critical component in the PTC system.

PTC refers to a flexible wireless system of monitoring train data including location, speed, track information, and equipment functioning. Information that is often gathered with the help of a Global Positioning System (GPS) is used to warn train operators about safety hazards. If necessary, the system can automatically slow or stop trains. With PTC, information is sent from the train to antennas placed trackside, where the data is relayed through another wireless system to the dispatch control center.

The RSIA, which was approved in October 2008, requires the biggest (Class I) freight companies, inter-city passenger, and commuter trains to implement PTC systems by 2015. According to the Federal Railroad Administration (FRA), a variety of components are needed ranging from digital data network to GPSs, on-board and dispatch computers, and throttle-brake interfaces.

The term "positive train control system" means a system designed to prevent train-to-train collisions, over-speed derailments, and incursions into established work-zone limits as well as the movement of a train through a switch left in the wrong position. Nine different railroad companies have PTC pilot programs in the US. Implementing the system nationwide in accordance with RSIA will require installing antennas in most railroad systems.

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