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All relay route interlocking : Signalling centre with electric security interlockings commanding train routes. Its functioning is completely based on an electromechanic cabling. This type of installations is now obsolete. The new signalling centre installed on the French railway network are either solid state interlocking or signal box with control computerized.
Announcement : Phone call or IT signal allowing to warn the distant establishment from the sending of a train in its direction.
Attention Device : Brilliant or sound witness allowing to draw the attention on a precise fact.
Automatic Colour-Light Signalling : System of safety and spacing of trains used by SNCF.
Automatic Restricted Permissive Block : System of safety and spacing of trains used by SNCF. Less expensive than the Automatic Colour Light Signalling, it also has a weaker debit. It is thus used on lines with a lesser traffic. This system implements mainly axle counters.
Automatic Train Operation (ATO) : System covering the acceleration, running and braking of trains automatically on information supplied.
Automatic Train Stopping Device : System allowing to provoke an emergency braking in the crossing of a closed stop sign.
Axle Counter : A device for counting the number of axles of a train passing a given point, so that two such devices will prove whether the section of track between them is clear or occupied.
Barrier Junction : Equivalent for the tramway of level crossings with automatic barriers for trains. Time of closures of barriers are however shorter, with reduced periods of safety.
Bidirectionnal track : In automatic block, indicate a track which can be crossed by trains in both directions.
Block System Assisted by Computing : System of safety and spacing of trains used by SNCF. It comes as a supplement to Manual Block, or to phone block system to reassure them.
Centralized Traffic Control (CTC) : Remote control from a central point of interlockings placed along a continuous route.
Complete Automatic Train Operation (ATO) : Reserved for the subway. It is about a piloting without driver, where the computing manages all the functions necessary for the progress of trains.
Contact Overhead Line : Very relieved catenary model consisted of a unique thread used for tramways, trolley buses or railway lines frequented by light trains.
Contact ramp : Device allowing the repetition of the signals in cabin. This device is placed in the middle of the track.
Dead man's handle : The system of the dead man's handle serves for stopping the train in case of illness or of endormissement of the mechanic. Explanation: the mechanic has to maintain non-stop a command of delay (button or pedal), otherwise he hears a horn, and after 2 seconds 1/2 an emergency braking is automatically made. Also, after 1 minute of preservation of the command in question, a bell rings and he has to slacken then maintain again this command.
Detailed Design : The detailed design allows the realization of the work, it has for object :
A) The elaboration of the functional plans, the technical notes and of calculation which precedent and order those detailed diagrams ;
B) The establishment of all the detailed diagrams, location and specification in aid of the construction site as well as the corresponding diagrams of synthesis ;
C) The establishment, on the basis of the detailed diagrams, a quantitative estimate detailed by package ;
D) The establishment of the projected calendar of execution of the works by package ;
E) To make the stake in technical coherence of documents supplied by companies when documents for the execution of the works are established left by the control of work, left by companies holders of certain package.
Detonator : An explosive capsule placed on the rail to give an audible danger signal to drivers.
Distance : An interval of time between two trains must be maintained. The spacing can be made by fixed distance, this is realized with systems of train detection (track circuit) which allows an automatic functioning ordered by the passage of trains. Other system is a spacing by variable distance which is used in European signalling ERTMS.
Double Track : Section of line in two tracks.
Electronic treadle : This system includes a magnetic sensor sensitive to the metallic mass of the wheel and a processing center which delivers an information to a conventional signalling relay.
European Rail Traffic Management System (ERTMS) : The European Railway Traffic Management System (ERTMS) is a major industrial project. ERTMS has two basic components :
• ETCS, the European Train Control System, is an automatic train protection system (ATP) to replace the existing national ATP-systems ;
• GSM-R, a radio system for providing voice and data communication between the track and the train, based on standard GSM using frequencies specifically reserved for rail application with certain specific and advanced functions.
ERTMS aims at replacing the different national train control and command systems in Europe. The deployment of ERTMS will enable the creation of a seamless European railway system and increase European railway’s competitiveness.
For more information on ERTMS see : http://www.ertms.com/
European Train Control System (ETCS) : 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.
Interlocking : Mechanical or electrical means of making the operation of one piece of apparatus dependent upon certain predetermined conditions being fulfilled by other apparatus.
Lineside Electronic Unit (LEU) : In ETCS L1, the LEU allows to send to the train the information important for the control of the train running.
Main line : Indicate tracks usually taken by trains on normal run.
Manual Block of Double Track : System of safety and spacing of trains used by SNCF. Former system based on operations insured by the agents-traffic, its safety was several put in the wrong times. It is coupled thus now systematically with the block system assisted by computing which largely reassured it.
Manual Block of Unique Track : System of safety and spacing of trains used by SNCF. Former system based on operations insured by the agents-traffic, its safety was several put in the wrong times. It is coupled thus now systematically with the block system assisted by computing which largely reassured it.
Manual stop indication : It commands the immediate stop for trains on cautious running or on shunting running (not announced).
Particular Junction : All the installations allowing the connection of industrial and commercial sites to the national railway network. A junction can serve one or several sites.
Phone block system : The most former method of management of the rail traffic. It is based on phone calls between the agents-traffic in the stations of crossing recorded as one goes along by every interlocutor in registers. This system is doubled now regularly by the block system assisted by computing, and very gradually replaced by the automatic restricted permissive block.
Point : Points and crossing with mobile rails allowing to pass from a track to the other one.
Points and crossing : The points and crossing are composed with rail elements, mechanics and electric elements.
Preliminary Design : The preliminary design is the first stage of answer of the control of work within the framework of a project of new construction. It has for object:
A) To clarify the physical, economic constraints and of environment conditioning the project ;
B) To present one or several technical solutions with a comparison of the presented elements and the lead times ;
C) To verify the feasibility of the operation.
Preliminary Project : The preliminary design has for object:
A) To confirm the feasibility of the reserved solution and to determine its main characteristics ;
B) To propose a topographic setting-up of the main works ;
C) To propose, if need, a decomposition in slices of realization and to clarify the duration of this realization ;
D) Allow the project owner to take or to confirm the decision to realize the project and to determine financial means.
Project Studies : The project studies have for object:
A) To clarify the global solution and the technical choices ;
B) To fix the characteristics and the dimensions of the various works ;
c) To establish a projected cost of the works decomposed into technically homogeneous elements.
Railway Signalling : Originally it gives orders to the mechanic (stop, slow down, whistle, lower the pantograph, etc.) or information (destination, origin, stabling). It aims at avoiding the dangerous situations (nose with nose, catching up, etc.).
Routes interlocking : A route interlocking implements multiple conditions and is maintained by the passage of trains.
The various types of route interlocking are: approach interlocking, transit interlocking, sense interlocking...
Running marker light : He allows to eliminate any risk of confusion enter a stop signal (not passable) and a (passable) semaphore when one of both red lights of the stop signal is burned out.
Service track : Used for secondary track (siding...).
Signal box (Interlocking) : Combination of the means of operating the signalling system of a track layout in a manner to meet the safety requirements of locking plans.
Signal box with computerized control : The pointsman acts on an IT console, what allows him to plan successive sequences of creation of routes for a long time before the passage of trains. On the technical plan, this type of equipment is an intermediary between the completely electromechanic all-relay route interlocking and the SSI (Solid State Interlocking).
Solid State Interlocking (SSI) : Signalling centre in which the safety is assured by the IT logic, contrary to the previous installations, where it was assured by mechanical or electromechanic means.
Stop Distance : Distance necessary for a train on the run to stop completely.
Stop signal : Not passable signal (purple or red stop signal).
Track : The track includes rails, sleepers and ballast.
Track circuit : The track circuit includes a transmitter and a receiver whose electric connection is assured by both rows of rail between two insulating joints. This connection is interrupted by the axles of trains. The disappearance of the signal constitutes the safety information delivered. It exists different track circuits : station track circuit, line track circuit and short track circuit.
Track-to-train transmission system : Signalling transmission system to the driver's cab by the track.
There are three track-to-train transmission systems : the TVM 300, the TVM 430 and the TVM 430 SEI (System of Integrated Interlocking).
Transponder-based Speed Control System : System realizing an automatic and continuous control of the speed of the train as well as a control of crossing of certain stop signs closed with an embarked computer.
There is analogical and digital transponder-based speed control system.
Treadle : Apparatus fixed to the rail and operated by the wheels of a train.

- AUDIBERT Jean-Claude, Signalisation ferroviaire, formation continue, 18-19 novembre 2008. ESTACA
- FERRO-LYON. Glossaire
- LE WEB DU RAIL, page Abréviations
- RETIVEAU Roger. La signalisation ferroviaire. Presses de l’école nationale des Ponts et chaussées : 1987, 619 pages.
- RFF, Annexe 2 Glossaire
- UIC - Collection of signalling terms
SafeRail - Your Railway Control-Command and Signalling Systems Expert
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