A train protection system is a railway technical installation to ensure safe operation in the event of

human error Human error refers to something having been done that was " not intended by the actor; not desired by a set of rules or an external observer; or that led the task or system outside its acceptable limits".Senders, J.W. and Moray, N.P. (1991) Human ...

Development

Train stops

The earliest systems were train stops, as still used by the

New York City Subway The New York City Subway is a rapid transit system owned by the government of New York City and leased to the New York City Transit Authority, an affiliate agency of the state-run Metropolitan Transportation Authority (MTA). Opened on October 2 ...

, the

Toronto subway The Toronto subway is a rapid transit system serving Toronto and the neighbouring city of Vaughan in Ontario, Canada, operated by the Toronto Transit Commission (TTC). It is a multimodal transport, multimodal rail network consisting of three Pa ...

, the

London Underground The London Underground (also known simply as the Underground or by its nickname the Tube) is a rapid transit system serving Greater London and some parts of the adjacent ceremonial counties of England, counties of Buckinghamshire, Essex and He ...

, the Moscow Subway (only on the older lines) and the

Berlin S-Bahn The Berlin S-Bahn () is a rapid transit railway system in and around Berlin, the capital city of Germany. It has been in operation under this name since December 1930, having been previously called the special tariff area ''Berliner Stadt-, Ring ...

. Beside every

signal In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...

is a moveable arm. If the signal is red, levers connected to valves on any passing train hit the arm, opening the brake line, applying the emergency brake, If the signal shows green, the arm is turned away from the levers and there is no contact. The

Great Western Railway The Great Western Railway (GWR) was a British railway company that linked London with the southwest, west and West Midlands of England and most of Wales. It was founded in 1833, received its enabling Act of Parliament on 31 August 1835 and ran ...

in the UK introduced its '

automatic train control 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 d ...

' system in the early years of the 20th century. Each distant signal had before it a ramp between the running rails. If the signal showed green, the ramp was energised with a low voltage current which was passed to the locomotive when a shoe came into contact with the ramp. A bell rang in the locomotive's cab to confirm the clear aspect, and the electric current kept the brakes from being applied. If the signal showed yellow (meaning the next signal would show red) the ramp was dead and a siren sounded in the cab. If the siren was not cancelled, the brakes would automatically be applied. After the nationalisation of the railways in the UK in 1948, this system was later replaced by the magnetic induction "

automatic warning system The Automatic Warning System (AWS) was introduced in the 1950s in the United Kingdom to provide a train driver with an audible warning and visual reminder that they were approaching a distant signal at caution. Its operation was later extended t ...

Inductive systems

In this system, data is transmitted

magnetically Magnetism is the class of physical attributes that are mediated by a magnetic field, which refers to the capacity to induce attractive and repulsive phenomena in other entities. Electric currents and the magnetic moments of elementary particles ...

between the track and locomotive by

magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nickel, ...

s mounted beside the rails and on the locomotive. In the

Integra-Signum Integra-Signum is a Swiss train protection system introduced in 1933. Originally it was called Signum; the name Integra was added later. It transmits data inductively and is simple, robust and reliable also in snow. How it works The locomotives ...

system the trains are influenced only at given locations, for instance whenever a train ignores a red signal, the emergency brakes are applied and the locomotive's motors are shut down. Additionally, they often require the driver to confirm distant signals (e.g. CAWS) that show stop or caution – failure to do so results in the train stopping. This gives sufficient

braking distance Braking distance refers to the distance a vehicle will travel from the point when its brakes are fully applied to when it comes to a complete stop. It is primarily affected by the original speed of the vehicle and the coefficient of friction be ...

for trains following each other, however, it cannot always prevent accidents in stations where trains cross paths, because the distance from the red signal to the next obstacle may be too short for the train to brake to a halt. More advanced systems (e.g., PZB, and ZUB) calculate a braking curve that determines if the train can stop before the next red signal, and if not they brake the train. They require that the train driver enter the weight and the type of brakes into the onboard computer. One disadvantage of this kind of system is that the train cannot speed up before the signal if it has switched to green because the onboard computer's information can only be updated at the next magnet. To overcome that problem, some systems allow additional magnets to be placed between distant and home signals or data transfer from the signalling system to the onboard computer is continuous (e.g.,

LZB Linienzugbeeinflussung (or LZB) is a cab signalling and train protection system used on selected Deutsche Bundesbahn, German and Austrian Federal Railways, Austrian railway lines as well as on the AVE and some commuter rail lines in Rail transpo ...

Radio-based

Prior to the development of a standard train protection system in Europe, there were several incompatible systems in use. Locomotives that crossed national borders had to be equipped with multiple systems. In cases where this wasn't possible or practical, the locomotives themselves had to be changed. To overcome these problems, the

European Train Control System The European Train Control System (ETCS) is the signalling and control component of the European Rail Traffic Management System (ERTMS). It is a replacement for legacy train protection systems and designed to replace the many incompatible s ...

standard was developed. It offers different levels of functionality, ranging from simple to complex. This model allows adopters to meet the cost and performance requirements of disparate solutions, from the smallest to the largest. The European system has been in operation since 2002 and uses

GSM The Global System for Mobile Communications (GSM) is a standard developed by the European Telecommunications Standards Institute (ETSI) to describe the protocols for second-generation ( 2G) digital cellular networks used by mobile devices such ...

digital radio with continuous connectivity.

Cab signaling

The newer systems use cab signalling, where the trains constantly receive information regarding their relative positions to other trains. The computer shows the driver how fast they may drive, instead of them relying on exterior signals. Systems of this kind are in common use in

France France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

and

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

, where the high speeds of the trains made it impossible for the train driver to read exterior signals, and distances between distant and home signals are too short for the train to brake. These systems are usually far more than automatic train protection systems; not only do they prevent accidents, they also actively support the train driver and detect blind spots around trains. Some systems are able to drive the train nearly automatically.

Variants

International standards

(Heavy rail) *

Communications-based train control 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 accurat ...

(Rapid Transit)

Country-specific systems

*By System **

ACSES 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 temporar ...

(United States of America) **

ALSN ALSN (Автоматическая локомотивная сигнализация непрерывная, in Latin - Avtomaticheskaya Lokomotivnaya Signalizatsiya Nepreryvnaya, meaning ''Continuous Automatic Train Signalling'') is a train cont ...

(Russian Federation, Belarus, Estonia, Latvia, Lithuania, Ukraine) ** ASFA (Spain) **

ATB André Tanneberger (; born 26 February 1973), better known by his stage name ATB, is a German DJ, musician, and producer of trance music. According to the official world DJ rankings governed by ''DJ Magazine'', ATB was ranked No. 11 in 2009 and ...

(Netherlands) ** ATC (Sweden, Denmark, Norway, Brazil, South Korea, Japan, Australia (Queensland), United Kingdom) ** ATCS (United States of America) ** ATP (United Kingdom, United States of America, Brazil, Australia (Queensland), Hong Kong, Indonesia, Ireland, Dominican Republic, Denmark) ** AWS (United Kingdom, Queensland, South Australia) ** BACC-

RS4 Codici RS4 Codici is a train protection system used in Italy. The term is an abbreviation of ''Ripetizione Segnali a 4 codici'' (''signal repetition system with 4 codes''). It is a simple cab signalling system, displaying the aspect of the next (and, in ...

/ -SCMT (Italy) ** CAWS (Ireland) **

CBTC 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 accurat ...

(Brazil, United States of America, Canada, Singapore, Spain, Gabon, Hong Kong, Indonesia, Denmark, United Kingdom) **

CONVEL EBICAB is a trademark registered by Bombardier (later Alstom) for the equipment on board a train used as a part of an Automatic Train Control system. EBICAB was originally derived from Ericsson's SLR system in Sweden. Most trains in Sweden and Nor ...

(Portugal) ** Crocodile/Memor (Belgium, France) ** CTCS (China) **

EBICAB EBICAB is a trademark registered by Bombardier (later Alstom) for the equipment on board a train used as a part of an Automatic Train Control system. EBICAB was originally derived from Ericsson's SLR system in Sweden. Most trains in Sweden and Norw ...

(Bulgaria, Finland, Norway, Portugal, Spain, Sweden) ** EVM 120 (Hungary) ** HKT (Denmark) **I-ETMS (United States of America) **

(Switzerland) **

ITARUS-ATC KLUB is the name of the modern Russian train control systems. The abbreviation "КЛУБ" stands for , ''Integrated Train Protection System''. Variants The most common variant is KLUB-U where the U stands for ''unified'' (). KLUB-U in-cab sign ...

(Russian Federation) **ITCS (United States of America) **

KLUB Potetball (also known as ball, klubb, kumle, komle, kompe, raspeball) is a traditional Norwegian potato dumpling. A similar German dish is called '' Kartoffelklöße''. The main ingredient is peeled potatoes, which are grated or ground up and ...

(Russian Federation) ** KVB (France) **

(Germany, Austria, Spain) ** LS (Czech republic, Slovakia) **LKJ 2000 (China, Ethiopia) ** PZB Indusi (Germany, Indonesia, Austria, Romania, Slovenia, Croatia, Bosnia-Herzegovina, Serbia, Montenegro, Macedonia, Israel) ** SACEM (France, Hong Kong) ** SHP (Poland) ** TASC (Japan) **

TBL Part of the troff suite of Unix document layout tools, tbl is a preprocessor that formats tables in preparation for processing with troff/nroff. Overview Mike Lesk is the original author of tbl. Like the main troff program, it uses command l ...

(Belgium, Hong Kong) ** TPWS (United Kingdom, Victoria) ** TVM (High speed lines in: France, Belgium, United Kingdom,

Channel Tunnel The Channel Tunnel (french: Tunnel sous la Manche), also known as the Chunnel, is a railway tunnel that connects Folkestone (Kent, England, UK) with Coquelles ( Hauts-de-France, France) beneath the English Channel at the Strait of Dover. ...

, South Korea) ** VEPS (Estonia) **

ZUB 123 The ZUB 1xx system is a family of train protection systems produced by Siemens. Its ZUB balises were deployed in the ZUB 121 train protection system in the Swiss railway network, in the ZUB 122 tilting control system in the German railway networ ...

(Denmark) ** ZUB 262 (Switzerland) *By country ** Australia - Queensland ( AWS and

) ** Australia - South Australia ( AWS) ** Australia - Western Australia (

) **Austria ( Indusi / PZB, ZUB 262,

) **Belarus (ALSN) **Belgium (

MEMOR The Gallienus usurpers were the Roman usurper, usurpers who claimed Roman Emperor, imperial power during the reign of Gallienus (253–268, the first part of which he shared with his father Valerian (emperor), Valerian). The existence of usurpers d ...

, TVM),

ETCS The European Train Control System (ETCS) is the signalling and control component of the European Rail Traffic Management System (ERTMS). It is a replacement for legacy train protection systems and designed to replace the many incompatible s ...

) **Brazil ( ATP, ATC) **Bulgaria (

700) **Croatia ( Indusi) **Czech Republic (LS) **China (LKJ 2000, CTCS) **Denmark (ATC, ATC-t, ATP, HKT, ZUB 123) **Dominican Republic (ATP) **Estonia (ALSN) **Ethiopia (LKJ 2000) **Finland (

900) **France ( Le Crocodile, KVB, SACEM, TVM) **Germany ( Indusi / PZB, ZUB 262,

) **Hong Kong ( ATP, SACEM,

) **Hungary (EVM) **India ( AWS, TPWS,

Anti Collision Device The anti-collision device (ACD) is a form of automatic train protection used on Indian Railways. Overview The ACD Network is a train-collision prevention system invented by Rajaram Bojji and patented by Konkan Railway Corporation Limited, a pu ...

, Vigilance Control System) **Indonesia ( ATP, PZB) **Ireland ( CAWS and ATP) **Israel (PZB) **Italy (

SCMT Sistema di Controllo della Marcia del Treno (SCMT) is a discontinuous train cab signalling system used in Italy. It shares many features with the Ripetizione Segnali (RS) system, the two systems co-existing and working together. The main pur ...

Blocco Automatico a Correnti Codificate Blocco automatico a correnti codificate (BACC or BAcc, ''automatic block with codified currents'') is a signalling block system used in Italy on railway lines using 3 kV DC electrification. The track circuits used to detect the presence of a train ...

) **Japan ( TASC, ATC, ATS) **Latvia (ALSN) **Lithuania (ALSN) **Netherlands (

) **Norway (

700) **Poland ( SHP) **Portugal (

700, named on the Portuguese Railways as

) **Romania ( Indusi / PZB) **Russian Federation (ALSN) **Slovak Republic (LS) **Spain ( ASFA,

900) **Sweden (

700, Ansaldo L10000) **Switzerland (

ZUB 121 The ZUB 1xx system is a family of train protection systems produced by Siemens. Its ZUB balises were deployed in the ZUB 121 train protection system in the Swiss railway network, in the ZUB 122 tilting control system in the German railway networ ...

, ZUB 262,

) **Turkey (Tren Denetim Sistemi (TDS)) **Ukraine (ALSN) **United Kingdom ( ATP, TPWS, AWS),

High Speed 1 High Speed 1 (HS1), legally the Channel Tunnel Rail Link (CTRL), is a high-speed railway linking London with the Channel Tunnel. It is part of a line carrying international passenger traffic between the United Kingdom and mainland Europe; ...

( TVM, KVB) **United States of America (

, ATCS, I-ETMS, ITCS)

Bibliography

References

{{DEFAULTSORT:Train Protection System *