Positive train control
From Wikipedia, the free encyclopedia (Redirected from Incremental Train Control System)Jump to navigationJump to searchA Metrolink locomotive decal on an MP36PH-3C stating that it is equipped with positive train control technology.
Positive train control (PTC) is a system of functional requirements for monitoring and controlling train movements and is a type of train protection system.[1] 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.[2] 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."[3] 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.[4] The American Railway Engineering and Maintenance-of-Way Association (AREMA) describes Positive Train Control as having these primary characteristics:[5]