Positive train control

Positive train control (PTC) is a system of functional requirements for monitoring and controlling train movements and is a type of train protection system. The term stems from control engineering. The train is only allowed to move in case of positive movement allowance. It generally improves the safety of railway traffic. Positive train control (PTC) is a system of functional requirements for monitoring and controlling train movements and is a type of train protection system. The term stems from control engineering. The train is only allowed to move in case of positive movement allowance. It generally improves the safety of railway traffic. Train protection systems are used to control traffic movement by technical means. They are especially needed in cases of high speed transportation, dense traffic with short succession of trains and mixed type traffic at widely differing speeds. Train protection systems were in practical testing at least since the beginning of the 1930s in Europe. Stopping a running train is the main goal of any train protection system. This is most easily done with stop order, and without a special order the vehicle is allowed to run. A typical representative for this 'negative train control' is Indusi. In contrast to this 'easy moving', a PTC restricts the train movement to an explicit allowance; movement is halted upon invalidation. The main concept of PTC (as defined for North American Class I freight railroads) is that the train receives information about its location and where it is allowed to safely travel, also known as movement authorities. Equipment on board the train then enforces this, preventing unsafe movement. PTC systems may work in either dark territory or signaled territory, and may use GPS navigation to track train movements. Various other benefits are sometimes associated with PTC such as increased fuel efficiency or locomotive diagnostics; these are benefits that can be achieved by having a wireless data system to transmit the information, whether it be for PTC or other applications. The Federal Railroad Administration (FRA) has listed among its goals, 'To deploy the Nationwide Differential Global Positioning System (NDGPS) as a nationwide, uniform, and continuous positioning system, suitable for train control.' The U.S. freight rail industry had said that at the end of 2018, the nation’s largest freight railroads were operating PTC across 83.2 percent of the required route miles. The American Railway Engineering and Maintenance-of-Way Association (AREMA) describes Positive Train Control as having these primary characteristics: With a decline in railway transit in the US after WWII, there was also less impetus for investment in train security. Near the end of the 1980s, a search for solutions re-emerged along with an inventory of technical possibilities. Starting in 1990 the National Transportation Safety Board (NTSB) of the US counted PTC (then known as positive train separation) among its 'Most Wanted List of Transportation Safety Improvements.' At the time, the vast majority of rail lines in US relied on the human crew for complying with all safety rules, and a significant fraction of accidents were attributable to human error, as evidenced in several years of official reports from the FRA. In September 2008, the US Congress considered a new rail safety law that set a deadline of December 15, 2015, for implementation of PTC technology across most of the US rail network. The bill, ushered through the legislative process by the Senate Commerce Committee and the House Transportation and Infrastructure Committee, was developed in response to the collision of a Metrolink passenger train and a Union Pacific freight train September 12, 2008, in California, which resulted in the deaths of 25 and injuries to more than 135 passengers. As the bill neared final passage by Congress, the Association of American Railroads (AAR) issued a statement in support of the bill. President George W. Bush signed the 315-page Rail Safety Improvement Act of 2008 into law on October 16, 2008. Among its provisions, the law provides funding to help pay for the development of PTC technology, limits the number of hours freight rail crews can work each month, and requires the Department of Transportation to determine work hour limits for passenger train crews.