An Advanced Train Control System (ATCS) is a North American system of railroad equipment designed to ensure safety by monitoring locomotive and train locations, providing analysis and reporting, automating track warrants, detecting blind spot and similar orders. [1]
ATCS specifications are published by the Association of American Railroads (AAR), and are designed to document the stated requirements of railway/railroad operational and technical professionals concerning ATCS hardware and software. [2]
The basic principle behind ATCS is to provide a cost efficient, safe, modular, train control system with an open architecture. The primary goals of the system are to provide for
The primary ATCS functions are:
The ATCS architecture consists of five major systems. Four of these systems are the information processing systems that reside at the central dispatch office (the Central Dispatch Computer), on-board locomotives (the On-Board Computer), on-board work vehicles (the Track Forces Terminal) and in the field (the Wayside Interface Unit). These systems collect, process, and distribute data with minimal input from dispatchers, enginemen, and foremen. The fifth system and the ATCS keystone, is the modern data communications system, which ties the various information processing systems together and significantly reduces the need for voice communications.
ATCS has been designed for modular expansion, which allows for varying levels of operational sophistication. Three basic levels of operation have been identified, although many hybrid configurations are expected in actual installations.
The Base Communications Packages (BCP) interface the ground segment to the RF segment of the communications system. Mobile Communications Packages (MCP) interface clients to the RF segment of the communications system or (optionally) to the ground system directly. MCP clients include wayside interface units, on-board computers, and track forces terminals. The RF segment operates at 4800 bits per second in the 900 MHZ radio band.
The Association of American Railroads' Task Force on Locomotive Systems Integration (LSI) has the mission to "develop a practical approach to the integration of the new electronic and mechanical components on locomotives" (per Minutes of Locomotive Systems Integration Committee Briefing to Locomotive Suppliers, September 5, 1991, Montreal, Quebec, dated September 11, 1991). An architecture to achieve this mission has evolved in the LSI Specifications which describe multiple configurations of electronic and mechanical components in a locomotive cab.
Dynamic braking is the use of an electric traction motor as a generator when slowing a vehicle such as an electric or diesel-electric locomotive. It is termed "rheostatic" if the generated electrical power is dissipated as heat in brake grid resistors, and "regenerative" if the power is returned to the supply line. Dynamic braking reduces wear on friction-based braking components, and regeneration lowers net energy consumption. Dynamic braking may also be used on railcars with multiple units, light rail vehicles, electric trams, trolleybuses, and electric and hybrid electric automobiles.
Cab signaling is a railway safety system that communicates track status and condition information to the cab, crew compartment or driver's compartment of a locomotive, railcar or multiple unit. The information is continually updated giving an easy to read display to the train driver or engine driver.
Centralized traffic control (CTC) is a form of railway signalling that originated in North America. CTC consolidates train routing decisions that were previously carried out by local signal operators or the train crews themselves. The system consists of a centralized train dispatcher's office that controls railroad interlockings and traffic flows in portions of the rail system designated as CTC territory. One hallmark of CTC is a control panel with a graphical depiction of the railroad. On this panel, the dispatcher can keep track of trains' locations across the territory that the dispatcher controls. Larger railroads may have multiple dispatcher's offices and even multiple dispatchers for each operating division. These offices are usually located near the busiest yards or stations, and their operational qualities can be compared to air traffic towers.
Automatic train control (ATC) is a general class of train protection systems for railways that involves a speed control mechanism in response to external inputs. For example, a system could effect an emergency brake application if the driver does not react to a signal at danger. ATC systems tend to integrate various cab signalling technologies and they use more granular deceleration patterns in lieu of the rigid stops encountered with the older automatic train stop (ATS) technology. ATC can also be used with automatic train operation (ATO) and is usually considered to be the safety-critical part of a railway system.
The European Train Control System (ETCS) is a train protection system designed to replace the many incompatible systems used by European railways, and railways outside of Europe. ETCS is the signalling and control component of the European Rail Traffic Management System (ERTMS).
Automatic train stop or ATS is a system on a train that automatically stops a train if certain situations occur to prevent accidents. In some scenarios it functions as a type of dead man's switch. Automatic train stop differs from the concept of Automatic Train Control in that ATS usually does not feature an onboard speed control mechanism.
Standards for North American railroad signaling in the United States are issued by the Association of American Railroads (AAR), which is a trade association of the railroads of Canada, the US, and Mexico. Their system is loosely based on practices developed in the United Kingdom during the early years of railway development. However, North American practice diverged from that of the United Kingdom due to different operating conditions and economic factors between the two regions. In Canada, the Canadian Rail Operating Rules (CROR) are approved by the Minister of Transport under the authority of the Railway Safety Act. Each railway company or transit authority in Canada issues its own CROR rulebook with special instructions peculiar to each individual property. Among the distinctions are:
Signaling and operation on the Washington Metro system involves train control, station identification, train signaling, signage, and train length. As with any working railroad, communication between train operators, dispatchers, station personnel and passengers is critical. Failures will result in delays, accidents, and even fatalities. It is therefore important that a comprehensive signal system operated by a central authority be in place. This gives individual train and station operators the information they need to safely and efficiently perform their tasks.
Direct traffic control (DTC) is a system for authorizing track occupancy used on some railroads instead of or in addition to signals. It is known as "direct" traffic control because the train dispatcher gives track authority directly to the train crew via radio, as opposed to through wayside personnel via telephone or telegraph, as in train orders.
Positive train control (PTC) is a family of automatic train protection systems deployed in the United States. Most of the United States' national rail network mileage has a form of PTC. These systems are generally designed to check that trains are moving safely and to stop them when they are not.
Advanced Civil Speed Enforcement System (ACSES) is a positive train control cab signaling system developed by Alstom. The system is designed to prevent train-to-train collisions, protect against overspeed, and protect work crews with temporary speed restrictions. The information about permanent and temporary speed restrictions is transmitted to the train by transponders (Balises) lying in the track, coded track circuits and digital radio. It was installed beginning in 2000 on all of Amtrak's Northeast Corridor between Washington and Boston, and has been fully active since December 2015, a few months after the 2015 Philadelphia train derailment which it would have prevented.
Digital model railway control systems are an alternative to control a layout and simplify the wiring and add more flexibility in operations. A number of control systems are available to operate locomotives on model railways. Analog systems where the speed and the direction of a train is controlled by adjusting the voltage on the track are still popular while they have recently given way to control systems based on computer technology.
Hitachi Rail STS SpA or Hitachi Rail STS is a transportation company owned by Hitachi with a global presence in the field of railway signalling and integrated transport systems for passenger traffic and freight operations. Hitachi Rail STS plans, designs, manufactures, installs and commissions signaling systems, components and technologies for the management and control of newly built or upgraded railways, transit and freight lines worldwide.
Pulse code cab signaling is a form of cab signaling technology developed in the United States by the Union Switch and Signal corporation for the Pennsylvania Railroad in the 1920s. The 4-aspect system widely adopted by the PRR and its successor railroads has become the dominant railroad cab signaling system in North America with versions of the technology also being adopted in Europe and rapid transit systems. In its home territory on former PRR successor Conrail owned lines and on railroads operating under the NORAC Rulebook it is known simply as Cab Signaling System or CSS.
Selectrix is a digital model train control system developed by German company Döhler & Haas for model railway manufacturer Trix in the early 1980s. Selectrix is based on a communication protocol developed originally by Siemens for communication between mainframe computers.
Anchorage Air Route Traffic Control Center (PAZA/ZAN) is located just outside the main gate of Joint Base Elmendorf-Richardson at 700 North Boniface Parkway in Anchorage, Alaska, United States. The Anchorage ARTCC is one of 22 Air Route Traffic Control Centers in the United States.
KLUB is the name of the modern Russian train control systems. The abbreviation "КЛУБ" stands for "Комплексное локомотивное устройство безопасности", Integrated Train Protection System.
Communications-based train control (CBTC) is a railway signaling system that uses telecommunications between the train and track equipment for traffic management and infrastructure control. CBTC allows a train's position to be known more accurately than with traditional signaling systems. This makes railway traffic management safer and more efficient. Metros are able to reduce headways while maintaining or even improving safety.
A ground segment consists of all the ground-based elements of a space system used by operators and support personnel, as opposed to the space segment and user segment. The ground segment enables management of a spacecraft, and distribution of payload data and telemetry among interested parties on the ground. The primary elements of a ground segment are:
Kavach is an automatic train protection (ATP) system indigenously developed by Indian Railways through Research Designs & Standards Organisation (RDSO). Initial development of Kavach started in 2012 under the name Train Collision Avoidance System (TCAS) and completed development in 2022.