A

ACCM

Interlocking Multistations.

APRs

Automatic Position Reporting System, radio based digital communications system for local, regional, or long distance.

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.

ATP

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.

ATO

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.

ATS

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.

B

BALISE

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

C

CBI

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 (ACC, MicroLok® and SEI/PAI-NG are the Ansaldo STS CBI interlocking). CBS: Communications Based Signaling.

CBTC

Communication Based Train Control, or CBTC, is a system that allows 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.

CENELEC

European Committee for Electro technical Standardization.

CTC

A Centralized Traffic Control system, or CTC, monitors the status of signaling 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. CTCS : Chinese Train Control System, a train control system used on railway lines in China.

D

DPL

Dedicated Passenger Line.

DTG

Distance to Go, Wayside and on board ATP system track circuit based.

E

ETCS

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

ERSAT

ERSAT is a latest satellite generation that interfaces and integrates the railway technology ERTMS (European Rail Traffic Management System) with the navigation and satellite positioning technology Galileo. The acronym comes from ER, for ERMST, and SAT, indicating the satellite technology.

ERSAT EAV

ERSAT EAV (Enabling and Validation) is the project, funded with the contribution of GSA, where new localization algorithms were tested together with the ability to integrate EGNOS and Galileo in the Ansaldo STS’s ERTMS solution, integrated with satellite technology and scheduled for ERSAT solution.

ERTMS

The European Rail Traffic Management System, or 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.

ETMS

Enhanced Traffic Management System.

EUROCAB/EVC

Onboard computer used to process ETCS information.

G

GCP

Grade Crossing Predictor, an electronic device which is connected to the rails of a railroad track and activates the crossing's warning devices (lights, bells, gates, etc.), based on a range of factors, including train speed, which minimizes waiting delays for drivers and therefore reduces the number of accidents

GNSS

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. GP: Generic Product.

GSM-R

Global System for Mobile Communications-Railway, an international wireless communications standard for railway communication.

H

HERMES

Automation-Supervision system used for mass transit system

HSL

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

I

ICSS

Integrated Control & Safety System. Integrated Communication Switching System.

IETO

Integrated Electronic Train Order

IXL

Interlocking System. 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.

L

LDS

Localization Determination System, satellite-based solution for train control system SIL 4 localization.

LEU 

Encoder. Product that is interfaced to balise and permit it to change the telegram to be sent to the train in the intermittent ATP according to the status of the route.

LRT

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.

M

MTBF

Mean time between failures is the predicted elapsed time between inherent failures of a system during operation.

MTBHE

Mean Time Between Hazardous Events, estimated time between two events that can cause an hazardous event.

MT

Mass Transit.

MV/LV TRANSFORMER SUBSTATIONS

A whole set of devices dedicated to the transformation of the voltage supplied by the distribution network at medium voltage (e.g. 20 kV), into voltage values suitable for the power supply of the low voltage lines (e.g. 400 V).

O

OCC

Operational Control Centre, system that monitors the status of signalling on the line and the location of trains.

P

PHPD

Passengers per hour per direction.

PM

Placed Movement.

PS

Power Supply.

PTC

Positive Train Control.

R

RBC

Radio Block Centre. All trains automatically report their exact position and direction of travel to the RBC at regular intervals. RBC sends by radio fail safe information to the train (ATP).

ROC

Remote Operations Centre.

S

SCADA

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.

SCC

Automation-Supervision system used for railways system.

SCMT

Sistema di Controllo della Marcia del Treno. Automatic train protection system.

SIL 0, 2, 4

Safety Integrity Level (SIL) is determined for components and systems with safety functions.

SSC

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

STO

Semi-automated Operation Mode.

T

TETRA

Terrestrial Trunked Radio, digital data and voice communication system.

TLC

Telecommunications networking.

TMS

Traffic Management System.

TSRs

Temporary Speed Restrictions.

TCCS

Train Conformity Check System verifies the conformity of running Rolling Stocks.

TP

Traction Power.

TVM

Transmission Voie-Machine (TVM, track-to-train transmission in English) is a form of in-cab signalling originally deployed in France and used on high-speed railway lines.

U

UTO

Grade of Automation level 4, in which there is no driver in the front cabin of the train, nor accompanying staff assigned to a specific train. This can also be referred to as Unattended Train Operation, or UTO.

V

VSS

Vital Safety Server used in freight application (both as for IXL and RBC).

W

WSP

Wayside Standard Platform.

WTIMS

Wayside Train & Infrastructure Monitoring Systems, a system that monitors the conditions of rolling stock and infrastructure in real time.