II INTERNATIONAL CONFERENCE__________
TRANSPORT SYSTEMS TELEMATICS TST'02
PO L IT EC H N IK I ŚLĄ SK IEJ 2002 T R A N S P O R T z.45, nr kol. 1570
rail control a nd management systems, fa il safe systems, railway computer networks Andrzej L E W IŃ S K I1
Lech K O N O PIŃ SK I2
C O M P U T E R N E T W O R K SY ST E M S F O R R A IL W A Y T R A N SPO R T C O N T R O L A N D M A N A G E M E N T
In the paper new system approach to computer systems based on computer network solutions for railway transport applications is presented. The basic network architectures with communication standards for dissipated management and control is an introduction to the hierarchical multi-level control structure according to theory of control and railway control classification. The several implementations of dissipated computer systems are characterised with respect to standardisation and safety aspects. The new technical solutions applied the fibre optics and radio transmission may be discussed corresponding to European Railway Traffic M anagement System (ERTMS). In the conclusions the actual problems and trends in computer network systems for railway transport applications are expressed.
SIE C I K O M P U T E R O W E W ST E R O W A N IU I ZA R ZĄ D ZA N IU T R A N SP O R T E M K O L E JO W Y M
W referacie przedstawiono systemowe podejście do systemów komputerowych opartych na sieciach komputerowych w zastosowaniach transportu kolejowego. Po omówieniu podstawowych konfiguracji i standardów komunikacyjnych stosowanych w rozproszonych systemach sterowania przedstawiono koncepcję hierarchicznego, wielopoziomowego sterowania zgodnego z teorią sterowania oraz z klasyfikacją przyjętą w sterowaniu ruchem kolejowym. Scharakteryzowano różne realizacje rozproszonych systemów sterowania zwracając uwagę na standaryzację oraz bezpieczeństwo.
Wprowadzanie nowych rozwiązali opartych na transmisji światłowodowej i radiowej przedstawiono na bazie założeń Europejskiego Systemu Zarządzania Transportem Kolejowym (ERTM S). We wnioskach poruszono problemy związane ze stosowaniem sieci komputerowych w zarządzaniu transportem kolejowym oraz aktualne tendencje rozwojowe.
1. IN TR O D U C TIO N
T he com puter netw orks as a support o f com puter system s for railw ay transport and managem ent have been im plem ented from tw enty years. W e may distinguish typical classification w ith respect to distance and volum e o f transm itted inform ation:
- pLA N w ith n ea r connections via local o r external buses and interfaces - LA N corresponding to E TH ER N ET, RS 232 and 485 (or sim ilar standards) - M A N related to X 25 and F ram e R elay com m unication
J Faculty o f Transport, Technical University o f Radom, 26-600 Radom, Poland, lewinski@kiux.man.radom.pl Faculty of Transport, Warsaw University of Technology, 00-662 Warsaw, Poland, jzw@ it.pw.edu.pl
94 A ndrzej LEW IŃ SK I, Lech K O N O PIŃ SK I
- W A N applying new inform ation technology w ith fibre optics and radio transm ission.
T he n et topology depends from given application:
- B us configuration in typical fail safe architecture including redundancy and self testing
- R ing configuration used always fo r transm ission in rem ote control and dispatcher system s
- S tar configuration connected w ith inform ation and ticket system s and supervisory system s for train and freights.
F ig.l. Dissipated computer networked railway control and management system
R equired integrity o f
safetv
C onsequences o f system fault
C haracteristics o f system
T yp e o f system
Ver>';high;,:: :T p :p w y q iV th e tra in F ail-safe system
( system
______________
Safety involved system
M edium Environm ental pollution
T o m anage the railw ay traffic L oss o r dam age o f
property
To inform the passenger
Low integrity system Loss o f non-safety
related inform ation N on-safety
related
To m anage the railw ay
F rom historical poin t o f view the first com puter netw orks in railw ay control applications are configured for safety purposes [2] such SIM IS (Siem ens) o r E B IL O C K (ABB Signal) applying the special solutions o f bus interfaces. N ext w e can observe introduction o f industrial net standards such RS 232 into coupled controllers in L evel P rotectioned C ontrol Systems [3], [4], o r m odem transm ission Industrial E thernet in L ine D ispatcher [1] system s produced for exam ple by A BB. N ow railw ay com puter system s use the fast radio transm ission based on G SM + tw o w ay standard and integrates w ith fast high rate optical network for efficient railw ay traffic m anagem ent.
2. T H E H IE R A R C H IC A L A PP R O A C H T O R A ILW A Y M A N A G EM EN T
F rom several years w e can observe integration o f m any com puter system s in th e form from F ig .l. T o each system com m unicating with other system s the safety level from 0 to 4 is assigned (T able I). It m eans that safety o f transm ission in each level m ust be considered w ith respect to existing standards (CEN ELEC ), [6 ],[7] recom m endations (U IC) [2] and requirem ents (national railw ay adm inistrations) (8].
Table 1 Systems Classification in Railway Control and Management
Safety critical systems Safety essential systems
T he standardisation com m ittee CEN ELEC suggests the follow ing assum ptions about reliability o f com puter system s applied in railw ay signalling and m anagem ent. C orresponding to assum ption that the ratio betw een safety integrity levels m ay be as 100:1, the com m on failure rates (regarding system level including transm ission) for subsystem s are:
N on-safety related system
96 A ndrzej LEW IŃ SK I, Lech K O N O PIŃ SK I
- System Integrity Level 4 - 10"9 h ' 1 - System Integrity Level 3 - 10"7 h' 1 - System Integrity Level 2 - 10' 5 h' 1 - System Integrity Level 1 - 10"3 h"1
T he com puter system s may be analysed from hierarchical point o f view typical to theory o f control. Such approach is show n on the F ig.2.
i L I N E j
I D I S P A T C H E R j
|_ S Y S T E M _ ■
A D APTATIVE LEVEL !
Fig.2. Hierarchical approach to computer networks in control and management
3. C O M P U TE R N ETW O R K S A N D D ISSIPA TED SYSTEM S
F or uL A N structures (redundancy and self-testing) the bus topology (including double and triple bus connections) is used. T h e Fig.3.a. show s the schem atic structures o f m ultiple com puters in interlocking controllers.
Som e netw ork techniques are very convenient for safety applications in transport system s. On the F ig.3.b the FD D I (Fibre D istributed D ata Interface) structure is presented.
T his standard o f fail safe com puter connections elaborated by A N SI before 1990 assures the
transm ission (synchronous o r asynchronous) to 100 M b/s in to several thousands m eters distance. T he F D D I applies the Dual R ing topology based on copper cables or fibre optics (with optical laser sw itch), in the case o f com puter fault the efficient by-pass is realised.
T he typical realisation o f W A N com m unication system s for m anagem ent and control purposes (dispatcher control and rem ote control) applies RS 485 standard (PR O FIB U S) from Fig.4.a. T his standard is convenient for rem ote control and rem ote supervision.
A nother W A N realisation, Fram e R elay standard (Fig.4.b), is typical solution for non
safety relation (level 0 ) o r n ot safety essential (level 1 o r partially 2 ) applications.
a)
C o m m u n ic a tio n C o m p u te r
M a s t e r C o n tr o lle r T e r m in a l
b)
Fig.3. The bus topologies o f railway computer network a) pLAN in interlocking fail safe computers
b) FDDI structure as a fail-safe support for computer LAN solutions
98 A ndrzej LEW IŃ SK I, Lech K O N O PIŃ SK I
T his standard use (like previous X .25 standard) package transm ission w ith error correction protocols (FCS) and virtual circuits betw een users. T his standard is a base of m odem netw ork K O LP A K -T applying the fibre optics and copper cables fo r fast transm ission in both synchronous and asynchronous m odes.
In this chapter som e practical solutions o f com puter netw orks in railw ay m anagem ent and control applications is presented. T h ese technical solutions reflect the actual state o f telem atics including new est achievem ents o f inform ation technology in P olish railways.
a)
Terminator
Transmitter Receiver
Terminator
T ran sm itter/
Receiver
b)
Fig.4. The W AN realisation, a) RS 485 scheme, b) Frame Relay structure
R edundant system s
T he bus connections in duplex structures presented on the F ig.5a . T he double CA N bus connection assure the fail safe operation, w ith com plex m onitoring and fau lt recovery is realised in program way. T his solution is elaborated by S cheidt& B achm ann for cross level protection system , and is a base o f fail safe control in other system s [2],[4].
The im plem entation assures the checking o f all bus signals, synchronisation and diagnostics of faulty m odules.
DISPATCHER TERMINALS
DIALOG TERMINALS
S B ¡ B K
STATION A REA
"É2E2É"
PROFIDUS Digitizing p»d Digitizing p»d
LOCAL CONTROLLERS I t e m
Fig.5. Computer network implemented in Polish railways
a) Bus connections in cross level protectioncontrollers (BUES 2000(pLAN))
b) Dispatcher centre o f WSKR (LAN) c) remote control o f W arsaw Underground (WAN)
D isp atcher system s
T he dispatcher centre for local m anagem ent has been installed in C racow in the form from Fig.5b. T h e com m unication subsystem applies single ring topology [1], the duplex structure is based on m ain com puter and hot stand-by com puter. F rom technical p o int o f view both com puters have the sam e, actual data sets and restart after sw itch caused by main com puter fault has no influence on dispatcher work.
100 Andrzej LEW IŃ SK I, Lech K O N O PIŃ SK I
R em ote control system s
T he rem ote control system applying the RS 485 (PR O FIB U S) standard is im plem ented in W arsaw U nderground [1], (Fig.5c). It is realisation typical to distributed industrial system s.
Both cable distances and transm ission rates is sufficient for m anagem ent o f trains from one point o f dispatcher centre.
C entralised system s
T he good exam ple o f com m unication system integration is centralised interlocking system E B IL O C K 850/950 produced by ABB w ith structure from F ig.6 . W e can distinguish pLA N and L A N /W A N netw orks and transm ission solutions typical for each layer.
Fig.6. The centralised interlocking with computer network hierarchy
4. CO N CLU SIO N S
T he railw ay m anagem ent system may be treated as a large com puter netw ork integrating typical com puter controllers dedicated to different functions on the distinguished levels corresponding to hierarchical m ultilevel approach. Such techniques com bine different net technologies related to pLA N , L A N and W A N structures. T he railw ay com puter netw orks apply different technologies: copper cables fibre optics and radio transm ission (G SM -R). The new standard, Fram e R elay (K O LPA K -T) is very convenient for railw ay traffic m anagem ent.
The transm ission param eters are sufficient fo r inform ation and ticket system s, freight monitoring and logistics. T he typical structure o f logistic centre is show n on the F ig.8 .
T he com puter netw ork may be assum ed as an approach to ERTM S project, w here all systems are integrated in the form o f one hierarchical system o f E uropean railw ays. T he co
operation o f m any com puter system s is regulated by U IC requirem ents and C EN ELEC standards. T h e safety o f such large system s depends n o t only on the com puter hardw are and software but som e technical solutions m ust be applied to transm ission corresponding to system integrity levels.
m u
n i rer
F i x e o p tic s Inks E the rne t 10 M ai R ailw ay Telecom
irei~oo~irenl
S w itc h 11 30/24 port
S e r v e r PC W ork Station
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PC W ork S tation J e t Direct
" t e - !
I 2 0 PC W ork Stations
“ V
PC Terminai PC W ork Station V 4 0 W ork stalion t/T e rm in a lt J
Fig.7. The logistic centre structure
B IB LIO G R A PH Y
[1] DĄBROWA-BAJON M., KONOPIŃSKI L., LEWIŃSKI A., W ybrane komputerowe systemy sterowania ruchem kolejowym na tle europejskich zaleceń normalizacyjnych, Problemy Kolejnictwa, Zeszyt 116, 1994 [2] LEWIŃSKI A., Problemy oprogramowania bezpiecznych systemów komputerowych w zastosowaniach
transportu kolejowego, Seria Monografie N r 49, Wydawnictwo Politechniki Radomskiej, Radom 2001 [3] LEWIŃSKI A., PERZYŃSKI T., Nowe rozwiązania komputerów sterujących w systemach sterowania
mchem kolejowym na przykładzie systemów ssp”, prace konferencji TRANSPORT W XXI WIEKU, Wydział Transportu Politechniki Warszawskiej, Oficyna W ydawnicza Politechniki Warszawskiej, Warszawa 2001
102 A ndrzej LEW IŃ SK I, Lech K O N O PIŃ SK I
[4] LEWIŃSKI A., PERZYŃSKI T., New computer control systems in Polish State Railways, I Międzynarodowa Konferencja Naukowa TELEMATYKA SYSTEMÓW TRANSPORTOWYCH, Katowice-Ustroń 2001
[5] LEWIŃSKI A., PERZYŃSKI T., Zastosowanie sterowników PLC w bezpiecznych systemach sterowania dla potrzeb systemów sterowania ruchem kolejowym, prace konferencji Wydziału Transportu Politechniki Radomskiej TRANSCOMP 2001, Zakopane 2001
[6] Railway applications: Safety Related Electronic Railway Control and Protection Systems, report on the standard EN 50129, CENELEC 1997.
[7] Railway Application: The specification o f dependability, reliability, availability, maintability and safety (RAMS), report on the standard EN 50126, CENELEC 1997
[8] Wymagania bezpieczeństwa dla urządzeń sterowania ruchem kolejowym, opracowanie Centrum Naukowo- Technicznego Kolejnictwa, Zakład Sterowania Ruchem i Zasilania, zadanie N r 1060/23, Warszawa 1997
R eview er: Ph. D. Jerzy M ikulski
