Contrôle de vitesse par balises
Encyclopedia
KVB or Contrôle de Vitesse par Balises ('Speed control by beacons') is a train protection system used on the French railways and in London St Pancras station
. It checks and controls the speed of moving trains.
KVB consists of:
The on-board computer generates two speed-thresholds based on the received signals from the balises. If the train is over the speed limit, passing the first speed-threshold, an audible alarm sounds and the control panel indicates to the driver to adjust the train speed without delay. If the second speed threshold is passed, the KVB automatically engages emergency brakes on the train.
The system is an adaptation of a similar Swedish
system, which uses an Intel 8085
microprocessor
. The first generation French KVB also used that technology.
The next revisions evolved towards a Motorola 68020
processor and the software was re-written using the B-Method
.
The decision to implement this technology was made at the beginning of the 1990s following accidents such as the Flaujac crash in 1985 and the 1991 Melun
rail crash.
Every locomotive unit on the French national railway network
, except those that operate connected to other locomotives, must be equipped with this system. More than 5,000 engines, including foreign locomotives that travel within France, are equipped. The TGV
is equipped with this system for all of its routes over conventional rail lines.
A European system for train control, called ETCS, will replace this and many other diverse systems in the various member states of the European Union
.
St Pancras railway station
St Pancras railway station, also known as London St Pancras and since 2007 as St Pancras International, is a central London railway terminus celebrated for its Victorian architecture. The Grade I listed building stands on Euston Road in St Pancras, London Borough of Camden, between the...
. It checks and controls the speed of moving trains.
KVB consists of:
- The on-board installation, known as bord (aboard), which comprises:
- an onboard computer (UEVAL) containing a processor, a communication unit and recording equipment
- A visual interface for the use of the driver, which
- permits data entry regarding the train's tonnage, length, category, etc.
- displays information about speed-limit and stop signals. Note that only warnings to stop and information about temporary speed limits are displayed. It does not replicate trackside signals for the driver. This is because the KVB is a relayer of information and does not constitute the entire signal system in force on high speed lines.
- An antenna, placed under the locomotive, to receive information sent by the ground installations.
- The ground-based or sol (ground) installations, made up of:
- Beacons or baliseBaliseA balise is an electronic beacon or transponder placed between the rails of a railway as part of an Automatic Train Protection system. The French word "balise" is used to distinguish these beacons from other kinds of beacon....
s - digital or analog transponders placed between the two track rails. These can be fixed beacons (sending a single set piece of information, e.g. placed at a point where there is a change of speed limit) or variable beacons (sending a variety of messages, so that one signal can send different sets of information as required). - A code box ensuring that the interface between the existing signal and the beacons can be switched.
- Beacons or balise
The on-board computer generates two speed-thresholds based on the received signals from the balises. If the train is over the speed limit, passing the first speed-threshold, an audible alarm sounds and the control panel indicates to the driver to adjust the train speed without delay. If the second speed threshold is passed, the KVB automatically engages emergency brakes on the train.
The system is an adaptation of a similar Swedish
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....
system, which uses an Intel 8085
Intel 8085
The Intel 8085 is an 8-bit microprocessor introduced by Intel in 1977. It was binary-compatible with the more-famous Intel 8080 but required less supporting hardware, thus allowing simpler and less expensive microcomputer systems to be built....
microprocessor
Microprocessor
A microprocessor incorporates the functions of a computer's central processing unit on a single integrated circuit, or at most a few integrated circuits. It is a multipurpose, programmable device that accepts digital data as input, processes it according to instructions stored in its memory, and...
. The first generation French KVB also used that technology.
The next revisions evolved towards a Motorola 68020
Motorola 68020
The Motorola 68020 is a 32-bit microprocessor from Motorola, released in 1984. It is the successor to the Motorola 68010 and is succeeded by the Motorola 68030...
processor and the software was re-written using the B-Method
B-Method
The B method is method of software development based on B, a tool-supported formal method based around an abstract machine notation, used in the development of computer software. It was originally developed by Jean-Raymond Abrial in France and the UK. B is related to the Z notation and supports...
.
The decision to implement this technology was made at the beginning of the 1990s following accidents such as the Flaujac crash in 1985 and the 1991 Melun
Melun
Melun is a commune in the Seine-et-Marne department in the Île-de-France region in north-central France. Located in the south-eastern suburbs of Paris, Melun is the capital of the department, as the seat of an arrondissement...
rail crash.
Every locomotive unit on the French national railway network
Réseau Ferré de France
Réseau Ferré de France , , owns and maintains the French national railway network. The trains are operated by SNCF, the national railway company, but due to European Union Directive 91/440, the French government was required to separate train operations from the railway infrastructure.Unlike other...
, except those that operate connected to other locomotives, must be equipped with this system. More than 5,000 engines, including foreign locomotives that travel within France, are equipped. The TGV
TGV
The TGV is France's high-speed rail service, currently operated by SNCF Voyages, the long-distance rail branch of SNCF, the French national rail operator....
is equipped with this system for all of its routes over conventional rail lines.
A European system for train control, called ETCS, will replace this and many other diverse systems in the various member states of the European Union
European Union
The European Union is an economic and political union of 27 independent member states which are located primarily in Europe. The EU traces its origins from the European Coal and Steel Community and the European Economic Community , formed by six countries in 1958...
.