Part of an Automatic Train Control System (ATC), providing both train detection and transmission of digital cab signalling data for the Automatic Train Protection (ATP) function of the ATC.


Automatic Train Control, or ATC, is an integrated signalling system that guarantees the secure movement of trains. ATC integrates various subsystems positioned on-board and wayside.  In addition to a full interlocking system, a complete ATC system consists of three subsystems: (i) ATP, (ii) ATO and (iii) ATS.


Automatic Train Operation, or ATO, is an ATC subsystem which performs on-board, non-vital functions normally performed by a train driver, including ensuring a smooth acceleration of the train to the running speed, speed regulation and smoothly stopping the train at the proper position at station platforms or in front of stopping signals.  ATO subsystems are primarily located on-board and represent one of the principal components of a driverless system.  Additionally, ATO subsystems report vehicle health status to the central control offices.


Automatic Train Protection, or ATP, is an ATC subsystem responsible for the safe operation of a signalling system.  It imposes speed limits on trains, both to maintain a safe operating distance between them and to comply with safety and speed requirements.  The ATP system is designed to be a fail-safe (vital) system.


Automatic Train Supervision, or ATS, is an ATC subsystem which operates to control trains automatically by means of ATO and ATP, in accordance with the railway timetable.  This also involves a CTC system.


Ansaldo Trasporti Sistemi Ferroviari, Transport Solutions Business Unit.



An electronic beacon or transponder placed between the rails of a railway as part of an Automatic Train Protection system.



Computer Based Interlocking, or CBI, is an Interlocking System (see below) where the traditional wired networks of relays are replaced by software logic running on special-purpose fail-safe control hardware.  The fact that the logic is implemented by software rather than hard-wired circuitry greatly facilitates the ability to make modifications when needed by reprogramming rather than rewiring.


Communication Based Train Control, or CBTC, is a system under development that will allow for the interchangeability of different technological systems in use on various metro lines.  CBTC can be understood as an attempt to create an ERTMS type standard for the mass transit industry.


The Companhia Paulista de Trens Metropolitanos runs the city of São Paulo's suburban passenger services.


A Centralized Traffic Control system, or CTC, monitors the status of signalling on a line or network and displays the relevant status information to a central operator, assists in the management of the line or network consistent with the timetable and exercises control to prevent small schedule disturbances from becoming traffic jams.  CTC also notifies the operator of ATC equipment failures and of failures in traction power and passenger station support facilities.



Dedicated Passenger Line.



The European Rail Traffic Management System, or ERTMS, ERTMS was introduced by the EU in 1992 as a means of creating a uniform system of command, control and coordination of rail traffic to allow for ‘‘interoperability’’ throughout EU territory.  The ERTMS standard exists at three levels (ERTMS 1, 2 and 3) depending on use, each distinguished by the type of wayside and on-board equipment used and the manner in which this equipment communicates relevant data.


The European Train Control System (ETCS) is a signalling, control and train protection system designed to replace the many incompatible safety systems currently used by European railways, especially on high-speed lines.


Onboard computer used to process ETCS information.



Ferrovie dello Stato S.p.A, or FS, the operator of the Italian railway network.



(Global Navigation Satellite System) satellite-based global navigation system, can rely on US GPS (Global Positioning System) or Russian GLONASS (Global Navigation Satellite System) or European Galileo system under development.




High Speed Line, or HSL, refers to railway lines with capacity for speeds in excess of 200 km/h (125 mph).



Integrated Control & Safety System.  Integrated Communication Switching System.

Interlocking System (IXL)

An interlocking system is responsible for the reliable and safe movement of trains inside a station, through complex junctions and for the length of the line.  The interlocking system ensures that train movement is permitted only when a route is available and the switches along this route are safely locked in their position.  In all cases the interlocking allocates a track portion or a route to one train at a time, excluding all others.



Light Rail Transit, or LRT, refers to a form of urban rail transit that utilizes equipment and infrastructure that is typically less massive than that used for metro systems, with modern light rail vehicles usually running along the system.



Wayside control system consolidating vital and non-vital control logic, data transmission and coded track circuits into a single package.


Mass Transit.



Optimizing Traffic Planner, or OTP, is a traffic management system that permits real time monitoring of the positioning of trains throughout a railway system.  OTP optimizes system or network capacity by safely minimizing the time between trains, thereby reducing operating costs.  OTP is primarily designed for those markets where railway systems infrastructure is being used to full capacity.


A large-scale programme implemented by RATP for the re-signalling of 13 lines.  OURAGAN is intended to standardize CBTC technology and diversify suppliers, based on the concept of interchangeability.



Positive Train Control: North American freight railway implementation of CBTC.



Radio Block Centre.  All trains automatically report their exact position and direction of travel to the RBC at regular intervals.


Réseau Ferré de France: manager, project leader and owner of the French national rail network.


Rete Ferroviaria Italiana S.p.A., or RFI, is a subsidiary of FS (defined above), responsible for managing the Italian railways infrastructure.


Rossiyskie Zheleznye Dorogi/Russian Railways is the state-owned railway company of Russia.



A Supervisory Control And Data Acquisition system, or SCADA, allows for the supervision of the various subsystems at work in a railway or mass transit environment.  SCADA collects information from remote installations, transfers it back to a central office, analyzes the information, takes appropriate action and displays that data on a number of operator screens.


Sistema di Controllo della Marcia del Treno: automatic train protection system.


Société Nationale des Chemins de fer Français.  The French National Railway Company is concerned with the operation of rail services for passengers and freight, and the maintenance as well as signalling of rail infrastructure owned by RFF.


Sistema Supporto Condotta: Italian train stopping system.  Less sophisticated than SCMT.



Trainline Controller provides an interface between CBTC equipment and the rolling stock’s conventional controls.


Train Conformity Check System verifies the conformity of running Rolling Stocks