telecommunications and signalling . on african railways

ECONOMIC COMMISSION FOR AFRICAUNION OF AFRICAN RAILWAYS

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ABBREVIATIONS

FORWORD

TABLE OF CONTENTS

E/ECA/CMU/42

l. INTRODUCTION 12. IMPORTANCE OF TELECOMMUNICATIONS AND SIGNALLING 23. AVAILABLE SYSTEMS FOR RAILWAY NETWORKS 3

3.1 Telecommunications 33.2 Signalling 63.3 Power supply 19

4. STATUS OF TELECOMMUNICATIONS ANDSIGNALLING IN SELECTED AFRICAN COUNTRIES 20

4.1 Cote i'Ivoire 214.2 Egypt 294.3 Gabon 354.4 Tunisia 434.5 Zaire 50

5. SUM¥JrnY OF PERCEPTIONS 586. PROGRAMME OF ACTION 637. CONCLUSIONS AND RECOMMENDATIONS 64

7.1 Conclusions 647.2 Recommeniations 66

BIBLIOGRAPHY 67

E!ECA!CMU!42

ABBREVIATIONS

ARENTO

ATC

CFMK

CTC

ECA

ENR

ITU

MAR

OCTRA

ONATRA

PCM

SCFB

SICF

SNCFT

SNCZ

SPG

SSB

UAR

UIC

Arab Republic of Egypt National Telecoclmunic-utions Organisation

Automatic Train Control

Matadi - Kinshasa railway line

Centralized Traffic Control

United Nations Economic Commission for Africa

Egyptian National Railways

International Telecommunication Union

Multiaccess radiotelephone

Railway Company of Gabon

National Transport Authority of Zaire

Pulse code modulation

R3ilway Company of Burkin3 Fasa

Railway Company of Cote d'Ivoire

Tunisian National Railways Company

National Rail~ay Company of Zaire

Supervision and Planning Group

Singlc Side Band

Union of Afric3n Railways

International Railway Union

E/ECA/CMU/42

roRWORD

An evaluation carried out by the Economic Commission for Africa (ECA)on the work of the Technical Commission of the Union of African Failways(UAR) on permanent Way, Interconnections, Signalling and Telecommunicationsrevealed that railway telecommunications had not received the attentionand priority it deserved in view of technological innovations in the sector.Peogress had been made in finding common solutions to maintenance ofpermanent way and search for standards but no substerrtda.L init:lativeshad been taken in the field of telecommunications and si~alling.

Railway signalling has generally remained simple and is now graduallybecoming obsolete. The philosophy has been that as long as trains operatedsafely, there was no need to invest in a system that was Viewed asunprofitable. It should be emphasized that the rehabilitation of pe::omanentway, rolling stock and equipment should go side by side with e. moderntelecommunication technology.

For the purpose of evolving future action progranmes , UAR and -ECAintend, by means of this publication, to disseminate the experiences ofsome African railway companies in this domain. This pUblication alsogives information on modern systems available on the market.

UAR and ECA wish to take this opportunity to express their gratitudeto the railway companies of Cote d'Ivoire, Egypt, Gabon, Tunisia and Zairefor kindly accepting to contribute to this study by giVing their approvalfor the mounting of fact-finding missions and provfdf.ng important dataand information .

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E/ECA/CMU/42

1. INTRODUCTION

An impressive growth in road transport and a correspondinglyconsiderable drop in railway traffic with regard to number of passengersand volume of goods, is the current trend in Africa south of the Sahara.

vlby should one seek an improvement in the African telecommunicationsand signalling network when in fact such an improvement could only bejustified technically and economically by an increase in traffic andrevenues?" The t\fo fundamental reasons for this situation are technicalhandicaps and technological changes.

Most African railways and telecommunication networks are technicallydefective due mainly to saturation and lack of reliability. The equipmenthas been mostly completely worn out, a situation further compunded bya chronic lack of spare parts due to shortage of foreign exchange or simplyto the fact that some very old equipment are no longer in production.

to replace old material, advantage shouldIn the industrialized countries, digital

widely introduced in the field of

Where there is the needbe taken of new technology.technology has already beentelecommunications and signalling.

However, it should be pointed out that digitization alone cannot solveall the problems. A great part of the analogue equf.pmerrt has been workingfor decades and will continue to work many more years, provided themaintenance is adequate and spare parts are available.

Concerning power supply, the use of solar energy will help to solvemany problems. This technology is well mastered today and the majorityof African countries can take advantage of their very intensive insolation.

This study, which has been prepared on the basis of information gatheredfrom some railway companies, aims at defining strategies for improvingtelecommunications and signalling in African railway networks.

E/ECA/CMU/42Page 2

2. IMPORTANCE OF TELECOMMUNICATIONS MID SIGNALLING

Telecommunications and signalling each constitute an integral partof the railways system. They should evolve at the same rate as railwaynetworks and their efficiency is essential for increased safety and trafficvolume as well as for maintaining a smaller number of staff.

Regarding telecommunications, station-to-station and diSpatcher linksare the basic services for operational needs. The more the network evolvesin terms of length and capacity, the more complementary services haveto be provided.

By means of the ground-train radio, routine and emergency communicationsare established between the train driver and the station or the dispatcherrespectively. It may also serve as a back-up system in case of failU!'eof the dispatcher links.

The shunting radio has to interconnect the signal cabin to the shuntingpersonnel for all information regarding train traffic within stationsor marshalling yards. Operating such a system may reduce the number ofaccidents and, consequently, increase safety for the staff ads well asequipment.

Besides voice communtcat ton , major railway networks also need textand data transmission. Telefax machines could gradually replace telexmachines, since they can be connected to existing telephone networks.

The importance of telecommunications for administrative purposes shouldalso be mentioned, for instance the links between regional directorates.

Finally, in the case of a total interruption of communications, aconsiderable volume of the traffic could still be handled, if a back-Upsystem was available. SSB links are a tested technology by which distantstations may be reached without passing through relay stations.

It is a fact, that signalling is a precondition for protecting trainmovement. Simple and rudimentary systems such as mechanical signallingin stations and telephone block as well as tokens allow for the operationof light-traffic lines. For the network capacity and traffic volume tobe increased through the use of double lines, a third track, other devicesand more rigorous safety standards have to be introduced by using moreefficient and sophisticated signalling systems such as electricalsignalling, single-track block, and radio signalling. However, the choiceof a too sophisticated system will imply unnecessarily high investmentand operation costs.

Failures in signalling equipment, especially within the block sections,have a serious impact on operation which can only be continued by writtenauthorization, unless a back-up system is available.

E/ECP-!CMU/42Page 3

3. AVAILABLE SYSTEMS FOR RAILWAY NETWORKS

3.1 Telecommunications

3.1.1 General

Railway companies, because of their specific needs, tend to usetelecommunication networks that are entirely independent of public networks.However, it is economically advantageous, that railway teleconnnunicationsshould, as far as possible, use the equipment and systems developed forpublic teleconnnunication networks and other applications. Specific needsof railway operations can be easily met by adequately adapting certainfeatures. This is true of both large railway networks and smaller ones.

If the number of subscribers is' low, the use of modern equipmentdesigned for the provision of telecommunications services in rural areaswill be very adequate. In this field, the combination of digitaltechnology, and solar energy, allows for the introduction of wirelessconnections to waystations and other subscribers in remote areas.

3.1.2 Switching

With regard to modern technology, the following techniques may beused in railway telecommunications:

(a) Digital transit exchanges;

(b) Small und medium digital subscriber exchanges;

(c) Digital concentrators (Figure 3.1);

(d) Digital multiaccess radiotelephone (VillR) systems to connect distantsubscribers (Figure 3.2).

Concerning transit exchanges, they will be conveniently combined withthe subscriber exchanges.

Digital concentrators, also called "remote switching units If, are themost economical equipment for switching, especially when the number ofsubscribers ranges from 30 to about 500. However, they can only be usedwhen connected to a host exchange containing a core unit for controllingthem. An interruption of the microwave or cable links to the host exchangewould usually cut the norrm.L operation of the concentrator, unless localtraffic is ensured.

Within public telecommunication networks, digital MAR systems aremainly used for subscriber access to local telephone exchanges as wellas for connecting telex subscribers and different makes have already beeninstalled in various African countries. They are basically composed ofone central station, repeater stations and subscriber or terminal stations.

E/ECA/CMlJ/42Page 4

Exchange

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E/ECA/CMU/42Page 5

Subscriber stations may be combined with repeater stations. Centralstations are normally connected to the mains supply, together with thedigital exchange, whereas repeater and terminal stations can easily befed by photovoltaic equipment. Experience shows th"t MAR systems withfive repeater stations and one subscriber station arranged in a cascadework satisfactorily. According to information obtained by manufacturers,up to seven repeater stf\tions can be configurated in a cascade, so thata total distance of about. 300 kms may be covered, if the topographic profileallows. This configuration makes these systems suitable for applicationalong railway lines.

3.1.3 Transmission

The nature of transmission paths depends basically on their capacity,length and the terrain. The following systems are suitable for applicationin African railway networks:

overhead lines;

voice or carrier frequency transmission on overhead or burriedcables;

PCM on symmetrical, coaxial and optical fiber cables;

(iv) narrow-band digital radio systems, (2 and 8 Mbit/s, 1+1or 1+0), for longhaul links;

(v) SSB radio links;

(vi) digit~l MAR systems for shorthaul links (Figure 3.3).

Investment costs and annual charges vary considerably between thevarious systems, depending on the distances and the number of pairs(channels) conducted in the respective link.

Traditional copper based systems with open wires are vulnerable toenvironmental influences. The circuit quality is variable, particularly,during heavy rains and thunder storms leading to attenuation of the signalstrength. They are also very often subject to. thefts which leads to abad overall service quality.

Optical fibre transmission systems are gradually replacing the copperwires. An optical fibre cable backbone will provide telephone and datalinks to wayside stations and support both voice and radio links transmittedfrom base stations to I1l()biles. The cables may be buried within the railwayreserve or fixed on exts't Ing poles. Solar energy equipment with batterybackup existing poles. . Solar energy equipment with battery back-up setswill provide the necessary lineside power.

As already mentioned in paragraph 3.1.2, MAR systems are basicallydesigned for use as rural subscriber access systems. However, in a cascade

E/ECA/Cmu/42P1j.ge6

configuration, they might adequately sqtisfy some of the needs of railwaytelecommunications (Figure 3.3), since they a l Lov for w.Ireless connectionof remote subscribers.

3.1.4 Ground-train radio networks

Ground-train radio systems provide communications between train drivers,traffic regulation centers, stations and track repair gangs. They consistof base stations and mobile units. As a means of uninterrupted radiocontact between train drivers and the dispatchers, they provide moreoperational safety, improved rationalise.tion of operations, and enhancedservices for passengers.

The radio transmission system uses a ground infrastructure w.l.th fixedfrequency transmitters and receivers placed along the rllilway line. Onboard the trains, mobile transmitter/receivers oper-at.e at trafficfrequencies that Ilre selected Ilutome.tically depending on the local frequencyused on the ground. The radio systems can be used as standby in the eventof failures in the telecommunication networks.

According to the recommendations made by the International Rai LwaysUnion (urc) and the International Telecommunication Union (ITU), the 450to 470 MHz frequency range hilS been reserved for train radio systems.

Figure 3.4 shows a schematic layout of a ground-train radio network.

3.2 Sign'111ing

Signalling systems are the nerve centres of railway. They contributeto safety, punctuality and rapidity of the railway operation.

The first systems date back to the very beginning of the railway,when token systems were introduced. Only the train driver holding thetoken was aut.hor t zed to circulate on a given line section. This methodis still valid and may be used on low traffic sections.

In the course of time, more sophisticated signalling systems weredeveloped, starting from the from mechanical through the electromechanicaltc the electric system w.l.th the purpose of operating signals and pointsand also preventing the occurence of false operations through theapplication of interlocking techniques.

Traditional signalling systems being well known, this document isconfined to providing inforTIk'ltion on the most recent technology.

Modern signal cabins have interlocking systems with geoPgraphicalcircuitry panels, from where the route track circuits are controlled throughrelay units. All positions of points, light signals as well as barriersare operated and interlocked by track diagrammatic push-button systems

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E/ECA/CMU/42Page 8

through the activation of electric relays. A "train describer"facilitate the identification of trains on the panel at any time.3.5 describes a typical railway station, and the train describeris shown in Figure 3.6.

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While rigid route track systems are used in small railwy stations,disPBtching in large stations is operated by means of flexible interlockingsystems. These systems are equipped with optical control panels and controldesks having push-buttons for route setting. The flexibility of thistechnique, enables routes to be set up modularw1se.

The operation of the geographical displays in interlocking systemsis through track circuit devices installed on each track section, whichallows for determining whether or nor the particular section is occupiedby a train.

Centralized Traffic Control (CTC) systems are used for centralizeddispatching over a long distance (up to several hundred km) from one centre.The operation may be carried out either by means of disp!\tch messagesto the distant signal cabins where the local staff executes the relevantme.noeuvres or completely automatically through remote control. It shouldbe noted that technological progress offers a number of sophisticatedinnovations which are however to be used principally on very importantmain lines having a very dense traffic as well as in large shuntingstations. The operations of the equipment in those CTC are based on digitalcomputers and panels where the track diagrammes are represented eitherthrough illuminated fibre optics or displayed on colour screens.

The traffic protection on a single-line is currently carried out bythe sing1e=l1ne block. From the moment a train is dispatched, no othertraffic will be allowed within the occupied block. With the interlockingof the electrical signal, neither the dispatcher at the departure northe one at the arrival point may carl'Y out any more manoeuvres withinthe respective block, unless the train has left it.

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Automatic block systems are widely used for signalling on double lineroutes. . All signals including those at level crossings are automatical.1:yoperated as the trains pass through the sections. The principle of theautomatic block system is given in the example in Figure 3.7.

Phase 1

A train arrives at section 1, 81 changes to red light (one light only),named semaphore;

Phase 2

The train occupies the sections 1 and 2, 81 and 82 are red;

Phase 3

The train penetrates total.1:y into section 2, 83 remains red, 81 changesfrom red to yellow: warning;

Phase 4

The train occupies the sections 2 and 3, 85 and 83 are red, 81 remainsyellow;

Phase 5

The train penetrates entirely into section 3, 85 remains red, 83 changesfrom red to yellow light.

The aspects of the signals may vary from country to country, dependingon national regulations.

Although single-line blocks and automatic block systems are internallyprotected against fa.ilures; that cannot exclude human errors. For thisparticular reason. additional· safety measures must be taken with regardto signalling.

Autol!le.tic train control· (ATC) systems use tl1.e t~hnique of mduct.tvecontrol of moving trains to avoid accidents or risks. In case the· traindriver does not respect main signals. warning signals or a compelled speedreduction, necessary measures or emergency braking are automaticallyactivated. These systems help to ing;irove safety for passengers and railwaystaff and to avoid damage to goods and rolling stock. ATe systems areessentially composed of car-borne and track equipment. By inductivecoupling, information is transmitted from the ground to the· .t.rain betweenbeacons located along the track and the car-borne receiver unit.

These systems transmit to the train driver information on the statusof the line on Which he is running as well as on the maximum speed··permitted. They also provide protection against breaking the speed limit

E/ECA/CMU/42Page 12

by compelling the driver to. respect the legal limits since all signalsare repeated on board.

The on-board central unit acts directly on the pneumatic train brakesvia a brake-system activation valve, if the driver does not operate thevigilance button within a given period, which may vary according to nationalregulations, af'ter he has passed a signal other than green.

ATC systems have several other features, such as the indication withinthe cabin of the target speed, failure counters, recorder units and others.

Figure 3.8 shows a typical configuration of the on-board ATCinstallation. A typical operational sequence relating to the train speedcontrol is shown in Figure 3.9, namely:

Phase 1

The train B moves near to train A which is preceding it.

Phase 2

The train B enters the last section where a green light, permits itto move forward at maximum speed.

Phase 3

The train penetrates the section having a restrictive yellow light.Here the train driver is given 3 seconds (for exampfc ) to recognize therestrictive information, otherwise the automatic braking is activated.

Phase 4

The train B enters a section with a maximum restriction (imperativered). As regards the recognition of the information, the same proceduretakes place. The approved speed limit is the one preceding a stop.

The end-of-train detection system allows for the automatic controlof the real presence of the last wagon of a moving train. For this purpose,the last vehicle of each train is equipped with a tail magnet which issupposed to transmit a signal at a given frequency to the detector whichis placed at the trackside of each station entrance. A diagram of theend-of-train detection is given in Figure 3.10,

The axle-counter system is also used to make sure that all train unitshave lef't a section. It is based on contact magnets which are fixed tothe rails at the entrance and exit, respectively, of a given section (seeFigure 3.11). Verification is carried out in the signal cabin by merelycomper-Ing the number of axles that have passed the magnets. One magnetcontact may be used for both directions ofa route.

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system' s advantage is thatIt is also independent of

As a matter of fact, magnetat level crossings.

E!ECA!CMU!42Page 13

no additional on-bard equipment istrack circuits, especially insulatedcontacts may also be used to control

Radio signalling or Radio electronic token block signalling (RETE)is a modern radio-based solution to the problem of signalling for trainson lightly-used lines. on which the high cost of installing, operatingand maintaining a full-scale conventional signalling system cannot bejustified.

All communication between the Control Centre and the trains is doneby radio. There are no lineside signals. apparatus. cases or cables.

In order to allow a train to proceed into a section. the system issuesan electronic token to the train indicating the appropriate directionof travel over that section. The token is r-ecefved in the driver's cabinin the form of a coded radio message from the Control Centre and isdisplayed as an authority to proceed. The respective section will becleared. once the driver has given up the token when leaving the section.

As regards level crossings. there are several solutions to automaticlight signalling which depends mainly on the availability or not of electricenergy from the mains supply. There are also mechanisms with or withoutsemi-barriers and in the last case. only flashlights. the St. Andrew'scross or acoustic signals are used. The installations may be operatedby solar power. Figure 3.12 depicts the typical sequences of an automaticlevel crossing protection system.

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E/ECA/CMU/42Page 19

3.3 Power Supply

The problems of energy supply in African countries cannot beoverstressed. In many areas, puhLtc electric energy is not provided atall or there are short or long energy cuts. Diesel generators or batterieshave to be installed for backup purposes.

The: practice of feeding telephone equipment in waystations, not poweredfrom the public network, from chemical batteries which had to be replacedperiodically dates to long ago. The signalling items of the equipmentwere and still are very often fed from a generating set. Compared tothese two techniques, solar energy is economically more viable, and requiresless maintenance.

Modern telecommunication systems for r-adLvays , except exchanges, havean energy consumption below 400 watts, hence power supply systems basedexclusively on solar energy can be set up in most sites within Africafor excellent overall cost effectiveness.

Signalling, consumes quite a high amount of energy. However, it issometimes possible to use solar power for signalling equipment, if itis operated only several times a day. In that case, power savers haveto be installed for reducing the energy consumption to a minimum whenno train is running.

Currently, investment costs for photovoltaic systems are generallyhigher than those for the other energy types, but the overall annual chargesincluding depreciation are considerably lower as there is no need forconsumables.

It is necessary to ensure that electronic equipment in remote sitesis able to work with only passive cooling-systems, since air conditionningwould not be available in phces without matns supply.

E!ECA!CMU!42Page 20

4. STATUS OF TELECOw.rJNICATIONS AND SIGNALLINGIN SELECTED AFRICAN COUNTRIES

4.1 Cote d'Ivoire4.2 Egypt4.3 Gabon4.4 Tunisia4.5 Zaire

E/ECA/CMU/42Page 21

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4 10)

Until 1989, t.h.: ra i Iwey Li ne Li nk i nc Ahidjan (CJt2 diIvJire) t »Ouaqad ouq ou (Bu r k i ria i:'.:::ZSJ) war, JperZlted by the;; Ab-><lan - Niger D'i r ac t or a t e(RAN) 0 Since Jun::,' 1989" f")11 :T"inq th(.::' s<?par.:.;\ti rn )f the RAN management 6 the

Railway Compariy )f C,t-:? d ' Iv »i r e (SICF) has h:~en Jper;;.ting the ssc t i on )f theline in C)te dv Iv oi r o , wh i Le, th',:' Railway C'I11"i?;my )f Burkina (SeFB) )per'"~tes

the pa r c in Bur k i na Fl.S)c A1TIi)st. ,::11 the s t r uc t u r e s and infrastructures )f

the tW) c nnpan i e s \_''2[2 i nhe r i t ed f r om Rl.No

"'::~:,_V'"' W·:IS c» s t r uc t ed dur i nqIS Jn2 ~~t~~ It is GJnsists

)( th.:::- '·,,;?ctiJn i r. C)te ,i~Iv)~.r'

19JO is 6j9 k"l /\nd t he ;:-:Ug2~irl~ se~vic1ng 35 st:1ti)os ~iJ

The Lenq t.h

th'2 per i xl 1904 ..

mainly 'E a single

ACCJ1'rling tJ s.t.e t i sc i.c s ):) t.hc! peri J',:' \TI,; 'I~:'

passonqe r t r e t f ic .h,)r'.~'f.:?;;.;, "",F JIl(Jt~'() t) 5~ac

pe r i )d, t h> Ln t.er no tf )n:11 Y;r "f ic 0(;t.I·,1~,:;;~ ».·'}mJuntfc'd t J 180000 pC'f;;s'::"''''''F;c:; ~,t ('~:.'p~'l:.ur::' It.ho at,)v;- p-vr i Jd a r ; n )t. ,,\7,") J"'.',l ,l,~)

.i.. "'1· - .I'.'r"'1\-' 1990" t hc rV:lti ")!"l2J

.j ".C; "'j>'?t"so 01Jrinq 'l':.h2 S3J:l18

;:::"~>':1.U--.: ".,,~\(] Bu rk i.n • F;:';5J

,'5 -)<:' e r r t vino tr:.1fi:i.; .f J[

The Jutg )in9 S) »Islev(~'l, 21mJUnb2li t) 1:.;.1) ~ DOCth'p i ntc-rne ti In-11 1'...,,; ",(? 1 ,t)ns (78 million t)ns-km)

t::'.,f::LIC du rinq t..,-: !.)'i!": ~L--:r:i. x; ...-:;1 the n,..yti )n'~1].

tl'(,g )(i" 'SG mi Ll i ». ,:~)ns 't' rc"sp,::ctiv(:ly)n ",n<~t')"(,

t) 31.0000 tons p" i .•.. )n t.)o,-km), v i t h 85,000

\ilith (i.~q?r"2, t) t~")l' r)1Ji;1q st. ick , SICF ':.1,i::~ ~., -) "!'";iJnS ,"'ln6 87 C)'JC~::;--'s, InS,~.pt,.--;,:nb(":!r 10'JO p t ho r ;:'\7.--.' L~i:;ility l";~)S 66% ""l[l' )7\; Y'::<~~J2(~'cjve.l,yo The ;"!1j'Y)'-·::- of1 )c)m)tivE:s, ('111 di.,-";::-,,,:'l r)';Jen~':}) ~~"<S 23 )f ,,:;h;.«:; 13 "cor ...' ?vJl.labl<2,.'the t )tal mnnbo r 'if t.be re i l.woy ope ra t I In scv.f f is 171;7 p~rs )n~

TeLec,rnmunic"iti)D t)i'~;ckb)ne Li nkt.h0 m)D)C xax ia l. cable ,,15 I'Jell ast rcrrsrnt s s i on sy s t em (SnC 48 1, ldc;:Jt<?l)

serve the linpsides pst~blishments.

is rnaJe Jf st~--!el P)sts,. wh i ch supp rr tthe ):'::';i'l m">;; ). r e lines, An .:in""l )gu JUS

is instaJJ.(;;'J )n tt:'.? m)!1)C »ax i c I c,-,hle t)

The

c 'imp )sedt) whi ch

p r iva t c t.e Lc pb cn-:of £ i. VE;' .-.d·:~ct r Jr.

a t)tal nUmb0[ )t

11":b,,r ) r k t;'l'i. '3 '.'C c );1 I),.; 1 :i{Vj' i.n~;

t.:.":'-I:Ch''''il':;2S -if +-.hE. ":L/~l.:) t:·r:nc'.'i:') s uhe r i n.sr s -i rc c :]'~ J(;C(:"

t) C)'Le d'!v)ire"is(J':,:-uFlJnt/Schneiner) p

SIeF ::.15) {1:'1S (' b:~.J.~:iraph nub:1)i,k at'LYch'2i)G€ )f th:.: 32n tyo,::::: (SAGE~'j)" :> ,-: l ac t r )roiJ

f)Y' n0,rm)nic t.·:~Je0r::'l?'·'! ),;:- c)l'ln:.':(:t:irp,Y~~t'1n(.

'l.r:;p);'::~l (fJhi.t::.h I nc Lud e s )(112

.\L.,_" t ··.":'.nt~·rs 1.nd S )\T!2 (."~:uipm.'?:;Jt

Disp~tching )D

;:mC! stati )n-t ),'-stnti):J;.ine-sjch·;; is - nro r«

li~~. Th~ ~isnatching

;,1 >:i'l':'; )f thi':' t eLsph )0(-':' bl )ckicc; J L'ut,,:;:,:! i.n Abi::!j"lnu

E/ECA/CHtJ/42Page 24

In 1978 p Rl\N WuS p.r1vidp.c ':lith g()l~n-:'-;··;:'~-:;.J J>-:-di") rr..:'twn:k (l\u~~)T)hyJ:)

which c ontr i but.e-S C:)!1';.i":~;;:)C1t.i~_'I· t) -s af e ):ty; r ":,, t -'. ) ·10 l~.;-)(': lin00 It i s CX1r)S'~C.

)t thr2e different r.YQ:::S )f equ i.pmon c, n~r;\,~_,:\i :_5-:·,....,;.:c:L~·r' w2sk'O fi!~·_J p1StSi n tho:: st.at i ons em] i.n)J):i.lC! ur i ts 1n bY.H'-; t bc ._1:""': ',c;. 'l'll:c.' <::is;~r1tch(;r ·4.'.~skc:; '2nLifixed s t at i on s in Abi:}j'::-ln '1P:: OU"1gr..:.))ug)U r (,J '::{i,:,. JYr3.r~' c onnec tr-d t) t hor ad I )-circuit whJcIJ i .....: f';-;{'( )f t;)f~ S~"J>Ii,':S i;: ;c." c;r~_f 1D sy s t.om, 'fhe I i nks

botween the clisp0.'cc:',,-,-~-rs ;:n,j (:;)bil,.;: units pes a L' ..f)v':~ll chc: f1Y:-d p rs t s which ':Jy

this way hand I e s th;;o:: \,o7ir2-F,Cii1 ,~ln·J radi)-;<1l.r· r ,>~l;!VC(S~')nso ~;J. C)IT]f,wnicoti)nsbetwf!vnthe l oc om rt i.vo s 2ncl uhe st,:~.ti);-js ':'::-: ,.'~" ")j,~,'~h,,>::: vir t:"~di) -v i t b i n t h..r0spec;tiv~..: p r )D'''0?,t"i)!j ?r;:~''''' ~ '15 r:~.?r(?s,:;nL.:{j ~n. ;>;2 ;··i.~!:L:,j 4~1. 2~

Th<::')p;::r,:>tti ),1 'Yi: to.. ,}?: )Un(..l-ti.':·::~~) ~:::",ji >':.:.

distributi In )[ th,:,>:~<:: rG~r:;.- ,t,.'';'( fCe:;ql»."nCl::'.C:::1. i '>' , ' );"',:

t) the principl.e (!e8cribe~ in p~r2g!~pn 3.1.

;l'~ n~·tw)rlc is b~s~C )0 thsii:t.i-,;r fr0qu":";1CY -::lee)r~ing

Th<2re is )nt:.' SGB r;\c~':'; link f or )(1(. r;'d::.i ),"",>. "\-:),_ ,~: be+-"I"2td th(' {:·"~sp;.~!tch:;:~r

cerrt r e s in Abid":!:~n a nd Ou"'gadJug )U"

Disp::ltching )f r"'·U,w~:.y tr"J1:fic bctwc'(:"n :st"ti. -:,pS :...s still c.s r r i cd Jut bythe: c Lasisica I rn,,·:thJd )f t.e l.epu onc b I ock , wherl.:.~;.-1s t h» stoti)DS ,"lrs :)r)tect<:~d bysignals. This si'Jn:.\ll'i.c~,g m"?thxI lS 11)( pr)b,:,'ct~1~ "iY ;ilY i nt.e r Loc kLnq a t e Ll ,The pr oq r e s s i ve sut.r t i t.uc i on )[ m.-ch on i co l si.qn':111ing hy ;o::'~.(;;C'trical Jights i.qrieLl i nq r'lt s t e t i »: ~,!ntrf'lnc(.?sp including t2tnJt12 c ont r o L )f p o i n t s t h r ouqh''-.dectric,:il mrt or s , as r>'l.rrL:d JUt. in 1980" i,'.1 n »; C'~~.V'2 th:?: EXt)l2ct(-:-d rc su Lt s ,

83 ther.·-J we re ~

tirr.:-;> s,~vins r

reductilD )f numb2r )f r)intiYl0 ~9(~nts?

inCrf2<1S1:: Jf s3:f,,·ty '·'J.~)il1 s-c>'-Jci )n:·:;,

I'he tel.?\?h )(},,~; b! )::::;..; is th>:; s i mpLc.s t SY5t.:: ':J »~,,-·i ncr s·;:f::c'.'ty f -Jr tVtins.betwc,en s t vt ions , If ..~ ':,,~:'1t.J.)n IT!"':',ster i-7F\l1tS 'i:;, ,'J Jet 1?:;q,K;ciib:, z: t'Ct7,!1~ her~qw;sts, thr)ugh ," tl;;10(/'~)n~ c i r cuit , en '.":;:'::; ''11Jthn·.i.??1ti)n fr),'!1 thenext s t o t i on , This ~r.)c:~dur:e c)mpl~..:t.;(; h,,' \11(~ -::~;."~ Cl.:?'1ri1nc,: ;-·!Jlr~tin vh icbhe hands »ve r t) thc i.:l·~l". d r i.v e r . ; ,!Ch, .')',.-vs.:_ ".1 L:; )'.. ir't'.::rl x:::Ke'rJIDi isroLiant on t hc pr:<·','S8~:.)n11 c incci )1..1,'-.i('k·SS, YC '(~'i~: '~F":r,::s \,<":) rnus t b~1 11) in<2':".n::;'2st:'1blish sir:'luJ.1:alk;1\Jsly 'i:'.1) r:;i,,:~r;:,:n~;~ cu Ll e: '~:, ~:):C th S,~hL: ol)ck sE'('~::i)r,y

Wh2never st~ti)ns ~r0 ~r)t~ct~~ by m2chanicrl~ .~ .~i~ in(~ with)ut int~zl)cking;

fi,Vi?("; refl(-=-ct)rlz;?LI '~:l:"'el,:,: "'lre i:lst~·!l_;,_:' ,·,-i.st,:;n(~~i thus :1.l'ilp,,,ll:i.ngC)i1Sci)Q':; runnin9 )'~ [/- ·r:"·i.n~ ;,\I?c:!:y";-,:;'c'J;:,'t)· 19'-"" IS .!.r"ls'2rt:,:,:,··1 ",t ::h r,'-

st;'ti)n "~ntrai1c':: whi.ch <!·:::ri~,its"H!t"riqq tt.··"·; be"' JD ",C ?- jTl,-:"!~:;.p.1Um ),f: 30km;:.l )nly, sinc12 thf? ?)ints"'lr,,:, n)t interl)ck<.:'d

InH)w,cv~::r r

(~qu i pt"e n t

4>1. 5.

C)te d'lv)ire, 18 st,1tiJns :-'J(:~re 00Ui'~}peu '''lith \?Iectrical siqnDLs.ther~ ~rc 'DIy five st~ti)ns, wher~ th0 el~ctric~l sign~lling

is stiil )p;;:.r21ti)ilal i, dlF' t) T,he prlbJ.-.;'::I:': ;:~~:scrib2-d :in p~r,')gr;]p;'l

Th0 ('nd-)f-troi., d<::t'::cti )!1 ('quipr:v:-:nt 'lunuiac~.:uc~d by th'2 c)mpany TRT~

~v)rks i~S descrih2rJ in pnr'lqrapl.1 3o.? B':lSi.c--JllY;J1J. t;-:'tl.ins chJuld be equipp,:'dwith end-1f-train mAgnets. i:)~~V8rw dl:? t) )r~r~tiJn,11 pr)b.10~sf th0seinst.:J.llati )ns havQ' n)t '.;"~-2n jnstall,:fl ;'c.d )':}''::-:' ~_" .~'r "II .Sit'2S (S(:2 p::t. ';,gr,l;Jh4.1.5),

E/ECA/CMTJ /11:;Page 2S·

Telecommunications and Signallingon African Railways

OUAGAOOt'GC'.

III

rl MI 1-- - I.

. LJ--- IFERKESSEDOUGCU I

- j

"


II!

II~,,

I'j.

i

II~!I

iJ1I,

I,!,

IiJr------------·l

I

Radio-link dispatcher to train driver

Example: Radio-link train driver to station

Example

IIJlIDJAN

___r,I I---u

RKESSEOOUGOU

• • n

E/ECA/CMU/42Page 26

4.1.4 P)wer supply

(CJncerning te:t.ec)mmunicati ons , tho exch;.:ng2s and r ad i » units f xrdispatching are fed f r om the mains. Each s t a t i on is pr ov i ded with a 48 v n esbattery pack. The fixed radi) units get their p)wer supply either thr)ugh themains )r by ph1t)v)ltaic equipment.

The s i qneLl.Lnq equipment is f od either fe)"'. the mains )[ f r om dieselq r oups backed by 8)13.r equ i pmerrt • H)wever, in the event )f failure of thediesel gr 1UpS, the s »l e r energy c ann 1t pr wide i'l permanent supply f 1r theinstallati xn , F'or this reas m they are equ i.pped ,dth special switches puttingthem under tensi)n )nly when a train is appr)aching.

feedmef.'DS

tr3ck

Signalling ba t te r ie s canV11ts )r higher v11tuges bylighting, pJinting m~chines,

Figure 4.1.3 sh )h'S th:;! ?l i nc i pL;,

4.1.5 Op8rati,n and mainton0nce

111 (~quipUl'2nti' :}ither, directly t"ith 24)f DC/Af; c )n\:~=rt'-;rs mai nLy f J[ signal

c i r cuic.. -:'nn:nd~)f-tLlin d0tect)rs~

Alth )ugh the Telec ommun i czrc i.on ~nd Si(~;·;v::LU.n~i D.:?p,:'1rtment is ~tt~ched t.,the Infrastructure Di v i s i )0 f the w)rk i nq cr:""";,1 " J.~:·C; classified i n t > f »urcircumspecti ons , arE: undo r three d Lf fe r e nt; s;:;cL. X'J~~ -~t the level )f Chief )fDepartment.

Tele(;)mmunicati )1)$ nne s i qn sLl i nq have .'J'2',-;i'! su:fr:"~~ring since a dQcad0 n)lIJf r om <3 chr »n i c Lack )f qU"11ifiE:d s t ef f Q Spd.":'2 p::':tt; end t ))18 nec,:ssary t)ensure g)Jd mai ntenenco )f i.ns t e Ll a t i orrs , 'rI~k' s·.:.~rvices are t.here f t-r e )ftenc )mpolled t., limi t th~:Elselves t., c )r f'~'ct.iVe ';.rJstead )f pr12v2ntivemaf.nt.enence , In the f ie Io )f signalling l in prir t i cu Lar Q the ;'}v,-dl"'blematerial is n) l)ng2r adequate f)r maintaining ~ll equipm2nt.

Regarding t.e Lec munun i ce t i 'ms where fn t ne time being the t o l.eph menetw)r.k is f unc t ion i.nq c rr rect.Ly , the s t ock )f spare parts f or the e Lec t r m i.cexchanqes is n) virtually 1_~xh3USt.?do On thr,:> )ther hand , th,,~ telegraph ne tw rr kis n)t 1)oger in )per3ti)n due t) failures in s)me circuits )f thetransmissi)n equipment"

VHth regard t > t.he q r ound e-t r a i n r ad i » equipr;ient l it s h au Ld DC? n rted thatthe links between dispatchers and t r a i n drivers arh-;': vice ve rsa IF1v-? st; Jpp&dw)rking. This is due t) bre akd owns )f ~:;)m8 "'.lxlules l)c:1ted )n theradi »-c i rcu Lt . H'Wl?V<2( r traffic b(:-tween trEl"ifF:.;w,:,l G~.:.;"t.L )OS ~nc; VI-Co2 \lcrs~ isbeing handled satisfact)rilyo

Ten ye()rs ag) th2 f orme r HAN had G"7iJ.lP'•xs.I 1;] st·--'\ti lOS wiU.1in C)ted ~ Iv)i re wi th electrical s i.qna Ll i nq , but )n1/ ,u: )ut. )[ chese w\.?r~; evc.nt.ue l.l.yput int) se rvrco , cur rent Iy , ~lGctric sign·:ll1.inr) is mire )r less Jperatedsatisfact)rily in )nly five stat i )ns} tbe r,~!'.:dnin9 s t.e t i JOS cnnn rt be putint) service due t) lack )f spare parts.

E/ECA/CMU/42Page 27

The reluctance t~ pu~ defective 2quipm~nt b3Ck lot) servicG, ~?par0ntly

can, be explained by the: f'lct that oLect rtc siqCl"'.'-'.ng did n rt fulfil thoexpaccat i ms , especially '";s c rnce r ns time S'1\n.ijCj ~nd r sduc t i on )f pJintingstaff in stati ms , Obvi »usLy t: reh·:1bi li tati J(! ».' t.h. pe r mnncn t; W:3.y sh )l1:td havepreceded the mode r n i ze t i on )f s i.qneLr i nq . F\,~:": since i:hE.'s~ measurvs h;::'\d n.,tbeen taken, the saving )£ tim~ achiev<?d by '..:hu i nt r xiuct;t In. )f alectricsignalling was n)t quite 1p~reci~D12o

The present tGcbn:c:.:l pi: )bl-~~n~s )'f. ,::l.e;'ct.r:: C s: ;.:;:1'1111ng ~r2 princ Ipa l lybused )0 the s i t.ua t i on JE -the t r ack-c i rcui t s , w'.lic:1 ,~r2 »f t.en )ut ;)f 1rJ12f dues lmetimes due t., l-".cl'" If insulati 10 between th::; i:r:-rc;, J L'1G'sr m.::dnly because 1fbre~kages )f the li'))den f i sh-ep l at.e s , but a181 ))~ 't.'~\.: ': r i p lccomcnt. by Hl~.?t;"llic

pl.tltes and , finA.lly due t) :~)Js.l"_) c )nt:"\cts caus ...> .. .r t oe oxpans i. 1n )f t rack s r.sa result )f hea t . ThGr2 are e l s i e f foc t s ),' -:..:.h2 linssida wf,ich oec xne sunc1-)rdinated with the ,~:g0nts in ch;:J.cg~: 1f ~~;_qn;·:i.lingo S)ffie »owe r supplypr ob.Lems were r'Zp1rted caused by the ageing )f th·,> h(\tb1ri'2s which have n ut;been replaced since their. i nst.eLl.ot i on ,

Basically p the s )lar energy equipmentstitisf:,ct.,rily. a l t.h ouqh there are s ome f au Lt smaking it i.mp rs s i b Le f)!: th<2ID t1 d i sc mnect. thehigh v)ltages c m i nq f r om cliesel q r oups , 'l'he r ..,24V/127V c)nverters cau",,,,d loy lightni.ngs.

f xr signalling is w)rkingin the regulat »r s , s omet ime sb0tt0ries during d~structiv~

hi: '.J~ e l s 1 beon breakd .,wns )f

A. Lab rr a t ory f or r cp a i r i nq ,]11 existinq .)(Juipment is .)t.tached t) theTelec)mmunicati )ns and i_g"l'''F'llling Ll-2i?llftm0t!to 0Ut its capac i t.y it: 5" f arlimited .,wing t) 12,ck )f S'')P1.'I;:':;, p;JrLs) p[JfeS3i1~1... ;:: c-)rJ,;.).,~c'nts ':;0(1 apprJr.ci~tB

measuring i ns t rumant s , 1'.~12r\; is a l s o 'in il'l.stiL:·:i,~;L·o'r.c.; ):( 2quip;Tknt. and st·Jff"The lack )f quaLi.f icd ")..;rs )n,~l C2n bo exp'l,"',J.D',:': 'y t.ho f,3,ct that l.J2tf-.erc md i t Lms arB .,ffen:c; in prlv.:Jt0 c ompan ie s.. ,~ -,-,::;:"',)m~n)n thf':t i nf Iucncasrecrui tment , Rep )rtGdly " many tJchn i c ians G) n ». ,~y:-.,c:r :i.nt., th2 52 rv ico .,f theSICF after having b~:;'2n tr:"~~ned in its '.rrc.i.niu,:] {.J,';:.~>:"

4.1.6 Quality)f servica

Weaknesses in Hkl:"IJ\:.~rLii·JCiJ as monti )Il~d in P::'.(':':igr::l"f.Jh 4.1. S) heve l,~d t) '1

roduct.I m in the qUi;'\li ty )f t(~lec »nmun i.c- ':':'1 1;"S -i"'Ja si;znt\lJ.ing fF:rviceoC1nsequently, S1ffi<:? )f i:)st.'~11at~.1,1S C".F' ]1) ·):'i'.;' I." '0 opc r e t i on .:lnym.,rc ~nd

th,se that are, w~rk uns2tisfact~rily ?r are tn ~ho ~t:~t0 )f dcteri)[!lti,n. Itis 1bvi JUS that. S"f0ty is .,bvi »us Iy ~t s t ako ~"';~::",:;-~

Thethe levelitself _

1rigine )f the !nedi »cr i ty in th\:! qual~t,; )f service can be tr.Jc8d t 1)f human and mat.o r i aj tess )U,:C,;:3 ,3:; If,r,,::!.::' as t) the 1rga.nizati 10

eJming t., staff, pets1nnEl assign€0 t~ the relev~nt s~rvices areinsufficient i.n number and d., n 1t a Lveys ).·1,3V2 t.,:1Q 'T~cessary qualificati m ,This is c)mp)unded by lack )t spare parts anJ l)gisti.c material.

4. L 7 Summary

Nearly all at ruct.urs s anJ infrastructures t}l'-: sreI.'" were inherited. fr)T'1RAN. The railway tpffic c )ntinues t) be disp:ltchv:: c'y t!h' classic ,1 t.ole"b )nebl1Ck methxL Ab)ut 80 p~r cent 1f the st3ti 111[; 11·:,''1'2 'ruch.3'1:i.~~1 sign{'ls~

E/ECA/CMU/42Page 28

The sp rrad i.c intr »ducri m )f <:::-::'8ctric ':::.iqn-:1L1.:(ng at stati 1n '2ntr<3nCGSdid not meet thp expcctati)n3 )f the former RAN ~s well as )f SICF, especiallyas r eqa rds a time sav i nq and r ecuc t i 10 )f t he numbe r )f p oi n t i nq 3g·:...'ntsu Thishas made maintenance )f this c qu i.pment; n) Lonqc r 0. pr i or ity S1mc,:)f thei ns t a l Lat.L )ns hav« c )nsequently been put Jut 11: s e r v i ce ,

P1wer f1r electric s i qnaLl i nq systems in s t e t i )ns wi t h out,is pr ov i ded by pl1",t)V11taic energy backed up ci c.sc l qe ne r a t o r s ,

)f this equipment is hampe r cd by sb xr t.eqe )f sparc p.vr t s ,

rna ins supplyMaintenance

rrhe t.e Lec ommun Lce t i 10 systVttlS h.l.ve been (::1ncei"lo2d in ,3 such:~s t) th8y

f xrtu a s o.l i.d ba s i s f)r r::--ihr::y n,~tt,.1)rk )p'2ra.i~.i)ns" Out lw;:c' ,~ls). part )f ';';"~'lC

equipment is 0) l)r,9';;,:'r in )r:.:~r:'jti)n dul,;! t) t.n: ;1)n·_·v"j.li:""1~)il.ity )f Sp:':{,::,: par t s ,

SICF' hr1S at its d iso rso L qu i t» ") l-,l: )): ',,;":;U' 1.""": -nt; -,f y'vancc:.;:u t(-:(:hn)l )-'~Y

capabIe )f playing ·~11 irnp)rtant r ")l<~ i":1 t.he :c,,:i,J'('j:'.y "}j}(;r,J.ti JF" H"~oieV\..'Tr dU0 t ')Inadequat,e ma i ntcnanc> ~"t i--'" \..1:)':'01,:, '(:) -x.r f ». ·;T"'i:·~l'y, In )rlh?r t) remedythese dof i c i.enc i e s , i L ~;iJ.l b;;? n;,,~C02SS"'lry t.) "_U", i:;:'h r; ......:;c Jrn.muni{,;:"",ti):-'I "Inc

signalling services with regard. t) tho::> 'VE;':;:~, J. ,rs: ",.. ; )ti.)n uno t., 3ssur:2 21mo r e regular supply -,f spere po r t.s 03nd .1 "}qLst:i.:; f'l~:<:r.~_ .I ..

As f or the pers"}r;n.·,l ::,h2r2 is 3 n,:;l2d t") -;{\SIJ,Y.·( i t s training in th:;:future.

4.2 Ee;:rpt

4.2.14.2.24.2.34.2.44.2.54.2.64.2.7

The national railways networkTelecommunicationsSignallingPower supply0& MQuality of serviceSummary

E/ECA!CMU/42

Pag 29

~------------

• H. Q

• R. D.. R.O (

LEGEND

CobbenMorsO •Mclroul".

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j,;!ECA CMU/42Page 0


Telecommunications and SIgnallingon African Railways

4.2.1

E/ECA/CMU/42Page 31

The national railways networlc

The Egyptian National Railway (ENR) Company has been continouslyexpandfng .its network by creating new lines and changing single linesinto double lines.

It is currently composed of about 3,000 kms of single lines and 1,000kms of double lines with a total of 800 stations. 549 locomotives servicethe lines and 236 are available for shunting. All. the tractive performancesare diesel operated. The rolling stock ,also includes 3,250 coachesapproximately and 10,000 wagons. The total.number of staff is 84,000.

During thepassengers andpassengers werepassenger-kms.

1988/1989 fiscal year, there were 535,526 trains for14,640 for freight respectively. A total of 650 million

tre.nsported during that period representing 38 billion

The freight sector handled a volume of 9 million tons, with an overallperformance of 3 billion t.on-kms , The medium turn-round time for wagonswas 11. 5 days.

The annual bUdget was subsidized with about 300 ,million Egyptian Pounds(LE) •

The ENR network configuration is shown in Figure 4.2.1.

4.2.2 Telecommunications. ---_._" _.- --". _._,.

The autonomous telephone network belonging to the Egyptian NationalRailways is composed of 15 private automatic analogous exchanges (Ericsson)whose installation 'NaS completed in 1982. It has a total capacity ofabout 1,000 lines. This network has no interconnection with the publictelecomrmmications networ-k (ARENTO) and is exclusively used by ENR toconnect

ENR management,dispatching and control offices,regional offices,important waystations,workshops and depots.

Local connections are two-wire lines (cables or open wires), whereaslong distance connections between the major locations, are done by carrierfrequency systems which are operated on coaxial cables or microwave linksrented from ARENTO.

The seven Regional Operations Control Offices (ROC) including Cairo,are based on small digital PABX configurations (Harris) which areinterconnected via DliF radio links.

E/ECA/CMU/42Page 32

A VHF radio communt.cat.Lons network, in combination with back-bonemicrowave Lfnks , provides dispatcher communications to trains over theentire length of track, as well as stand-by communications to selectedwaystations and signal cabins.

A tender has already been opened for the supply and installation ofadditional communications equipment for the operations control system.

4.2.3 Signalling

The ENR operates mechanical, electromechanical and electric signallingsystems most of which are mechanical on single as well as double linesin Upper Egypt, except for a length of 90 kms. In Cairo and its environselectromechanical and electric systems are working.

Tokenless systems (Tyries) are widely introduced on sf.ng.le and doublelines for block systems between stations (i.e. if there are no other signalson the respective section). Token instruments are used on some singlelines.

Electromechanical signalling systems represent a half-way passageto electric signalline. By applying this technique, all original leversfor controlline signals and point machines still exist and are operatedas before, including their mechanical interlocking system. However, thelevers are no longer pull steel wires or bars, but rather operateelectricalcontacts which in turn control the electric motors for point machinesand signal lights. Mechanical barriers at level crossings have beenreplaced by intermitting lights.

The fully electrically operated signalline; systems are being installedfor the purpose of Centralized Traffic Control (CTC) , thus allowingautomatic control of all train movements. In this system, electric relayscontrol point machines and signal li"hts, while the actual situation ofpoints and signals is indicated on a geographical circuitry push-buttondesk. By activating the train describer system, trains can be identifiedon the panel by their respective numbers.

Automatic Block Systems are operational on high-density traffic lines.In these systems, basicially all signals are always cleared. A trainhaving entered a given section, protects it by immediately locking theblock which it has just passed. Simultaneously, signals in the sectionsbefore the last block are set to different positions, thus compellingthe following trains to reduce their speed.

The lectric CTC withintroduced in 1956. It vason that respective line.

push-button technique (ALSTHOM) was firstabandoned when the Cairo Metro was constructed

In 1963, awas installed.

newer generation of inter-locking system (Siemens DrS)This system is still operational. Recently installed

E!ECA!CMU!42Page 33

inter-locking systems are mainly of the ms 801 (Si-emens) type.

Currently, about 260 kms of the nat.LoneL railW'ly lines are operatedwith CTC systems. Equipment. has been installed for another 23 kms, awaitingto be put into service. Contract has been awarded for the installationof another system for a further 110 kms.

Electromechanical systems cover about 130 kms .or the network. Withint~ese systems, several signal boxes have received fully electrical equipmentin such a way that they constitute "electric islands" in anelectromechanical environment.

,I Automatic Train Control (ATC) is usually also introduced on railway

lines with high traffic. It automatically compels a train to reduce speedand eventually stop completely if the signals are not respected accordingly.

4.2.4 Power sUPPl,y

If mains supply is cut or isis supplied by diesel generators.sites are fed by local batteries.for telecommunication purposes.

not available at all, electric powerIndividual telephone sets in remote

Solar energy is used in many places

4.2.5 Operation and maintenance

The operation of telecommunications and signalling is considerablynanpered by frequent breakdowns of equipment. For example, the faultstatistics for July 1990 show a total of 187 breakdowns in signallingequipment, mainly caused by damages and theft. Seventy-seven of thesefaults could be cleared only after a relativel.Y long period.

In the telephone network, the monthly availability of the systemswas varied, during the period April to July 1990 by between 45 per centand 100 per cent, depending the respective regional operation. centre.The statistics show that telephone systems based on wires are highly proveto breakdowns.

Field visits have shown that maintenance of relay and power-supplyrooms needed to be improved. This is particularly necessary for airconditionning and protection against dust. Failure to take these measureswould reduce the life span of the equipment. t. higher priority shouldbe granted the repair of ENR owned cables for CTC systems, for safetyreasons.

E11R operates a workshop with a telecommunications and signalling branch.The telecommunications workshop is capable of handling all current repairof equipment. For sophisticated electronic parts, an in-circuit teststation is available. Furthermore, all mechanical inter-locking systemsare mnufactured in the signalling workshop.

E/ECA/CHU/4.2Page 34

4.2.6 Qlli~lity of service

There is room for improvement of the quality of service with regardto telecommunications and s LgnaLl.Lng , The frequent theft of copper wirescould only be avoided by introducing more wireless transmission systemsor optical fibre cables. The operation of the telephone network couldbe improved by introducing more transmission links, thus enabling completeinterconnection of the exchanges. Currently, some of the telephoneexchanges are not connected to the ENR national telecommunications network.

There are maintenance deficiencies due to the fact that most of thetransmission systems belong to the public t.e.Iecommurrlcat.Lon organization.However, its maintenance regulations are not always suitable to ENR needs.

4.2.7 Summary

ENR has modern electric signalling systems on important line sections.There is no doubt, that conventional systems can still satisfy the needsof secondary routes.

By giving more importance to telecommunications, efficiency and safetycould be further improved. Initially, a cOnsiderable investment willbe required to enhance telecommunications, specifically by:

(a) Creating inter,rated telecommunication and signalling systems,

(b) Replacing wire connections by radio links or fibre optic cables,

(c) Establishing an ENR owned transmission network,

(d) Introducing such modern operation technologies as telefax.

Maintenance should be reorganized in order to increase its efficiency.The introduction of controllers both for signalling and telecommunicationsmight be a useful support of those efforts.

4.3 Gab m

E!ECA!CMU!35Page 35

4~ 3~1 'I'he nati )nal r a i Iways ne t.w rrk

4.3.3 Signalli~g

4.3.4 Power supply

4.3.6 Quality)f S2r1nCe

4.3Q7 Summary

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Projected line---

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Telecommuoicatioos Dod Sigoalling00 African Railways

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E!ECiI!CMU/42Page 37

4.3.1 The nati,nal railway net ...... 'rk

The railway ne tw xr k )f the ':era:1S-Gab)0 Hatl\A2I.Y Autb xr i t y (OCl'RA.) isc ompased )f tW) secti ons , namely OHench (Po r', );' -::"lhreville) - By)ue and B))ue- Franceville with a t )tal lenqth )f 648 k::n '.I'~2 l.i ne \"as c ons t r uc t.ed duringthe pe r i od 1978 - 1986. It is a single Li.ne ~dt.:;! (.< gauge )f 1.435 iVl (~-ee

figure 4.3.1).

Pr om 19:;n, the ne tv ar k will CYi1J?r:;.S{~ Lt,~ta.L~-.md t) be pr ov i ded t.Jithsignalling and t e Lec ommun i c a t ions facilities "H',: 'Jr~~i.l as t:~N.)·-'.:"';l·y· s t e t ions .

Ace Jrd ing t) stat) s t i c s )n 1989 ~ t tr- tr: -:d.:v:; pe r f ormences a r e asf ol l ows s 31 diesel 11c)"111t:;ves, 2 l)c')trac"~)r~i 2::'" 2 passenger rail carshaving an ava i Lab iLity of Q('I1ut 67 per cent, ':fT,',' nF'I;I.:-er 1f wag 1ns was then1165 )f which 282 '.....e r e privately )WnAr'e ·'"here~~~,> t:)e nl;;~l.~;~r )t c iacbe s was 37units, including 5 rail ca r s . ,r...~"; r e qe r d s th.'? -':.. a,:l1 -iraf f i c , there were 540passenger trains an-" 2800 9 1",)·.~S trains !r: o-J:-::': tj -):~ t") ':"_hi,s,! 520 p ri ve t emineral trains were rUnnlnga

Again during the year 1989, therni Lk i on t. ms , )r 1.2 b i Ll.ion t ons -Rm ,external operater (CO'\lILOG),

q oxl s t r a f f icThis traffic

reached a v rLumei nc Lu-re s the »a r t

)f 204of an

The statisti.cs put that the t xt a I numbe r oC pas sonccrs at 130,000pers)ns, which c)rresp1nds t) 54 milli)n passengers-km. Still ,during the sameperi>ct, the )perating C)sts a~)unted to 1506 ~il1j)n.CFAF, of which 3,4billi)n had t) be subsidized.

The number )f staff was then 1,854.

4.3.2 Telec)!.1lillunicati )0:-:';

The telec ommun i cat i on o'~t\·nrk is 2qU:i.P,?'2i;i

exchanges (J2um )ntjSchnejJ":>r) with a 1:. ')tal caQacL-.~·

',d. th five d iq ital)f J" 600 Li nos,

,JlEil'EL

Regarding ttk: "Ll::al.s~ljissi)n S2Ct)(v d'",:; ~_:,,,-:ct.;.)n Ow<;.>nd) B))U2 ispr )vided with a SMC 120 muLt i p l.ex sys t cm Sh'I_U.c'· t') -;::1F' eI'l' ALCi-\'rEL t,~chn)1YJYwhich uses a bu r r i ed ITl,)n)c v~xial c3.blc: . ::~:;; (ci.)a.sity)f 120 supp rr t

circuits. T~Y2 link is i:1 '·'ill b,_:~ c onc r ol lad '0y c: ~~:;~nL:alizeJ c omputo r systemt) be put i nt.» sc rv i ce ;,)y N)vemt.\,~r 1'J900 'l'h., 5:~ct,_)r 'R))W? - i?ra;")r;;'-"Jil1e isals-,eguipped with inalJgu)us t r acsm i s s i on '~:Y:;i,"-·,"<l LJ tOi'l'.' 51'Ii. 48 1r: a bu r r i.cdm)n)c)axial cableo

Apart f r om general t e Lc ph )r:y I' the :1;))\1 .:

dispatching as well as f cr stati 1n-t )-stati)':1 lin~.::;

to be exchangGd.

,~:,~-uipment is lIse{: f)r.;lh'2re s a f o t.y mes s aqe s have

In case )f breakd)wn )f the aut)diallin1 dispatcher circuit~ a sse ra~i)

link allows f xr c rmmun i catt m with all st.a t tons situated a l onq the firstsecti )0. This circuit is backed. up by a d i soa t cner Li.n k )n a 1 )w-frequencycable.

The stati 1n-t )-stati on link yE th':~ first s-:~cLi)n is backco by stand-byVHF r ad i o links (Motor)la), whereas )n the s3<:)n,1 sec t i on it is backed bystand-by stati )n-t )-stati 1n links c onductod )n th2 1 )",/-Er,,"qu<?ncy c ab l.e ,

E!Ec.'\/CMU!'l2Page 38

A q r ound e-t.r a i n r ad i » tslepn1ne sy s t em \!m~)p,",)n) is i.n s t a Ll ed all alJngthe 1i08. Its characteristics are identical ~ith thlSG described in ch~pter

.:Ll.2 )0 C)te d t Iv oi r e . Due t) 1p.?rdti1nal a nd ma i nte nance p r ob Lems , thissystem is OJ 11nger Jperati)nalo

4.3.3 Signalling

Fr)11l 1991 )nw~rds~ 21 OCTRA stati JOS j;7ill ~....~ pr ov i.dod with '212ctricalsignalling including e Lec t r i ca L man y?uvres )f the main p r i.n t; raach Lnes •Entrance and exit signals will be c ont r 1112(1 by a (bsk t) be i n s t al Lcd '·r~.th

the dispatcher Wh1 1>1i11 a Ls o have a li,ghting·»[\,d ;1(: ~,'~::', d i sp xae l • All s e f e t.y.CunctiJns c once r n i nq a s t a ti on :c:r·:~ )!?Grati.-~d fr.)t~'--;~;\lcct.rica.l r e l ay cabin bymeans )f a right iliter11ckinq system u~.LS'l'aor/i) I.Ch::.:.' iilc-::J.l> l i ne s in the s t a ti onsare equipped with t r ack-c i r cu i t s , which <?n~ c1nn:'ct.0C: t1 t he respec t i.velighting pane L,

Originally, a],l si.gn2ls wer2 preceded hy 2 ~~~ Jf ~2~C1ns, Jn2 )f th~rn

being j:ix~?d. out s i de th·:: tr<tck and the »the r :-:."."; 1-'SeC,(1r aut)m~',ti..c::rain

c1ntI11 (ATe) 0 In aa,:liti »n , trains W:::~t:"0 equip,?'2--< vtt..11 .naqno t s f or <2nd-)t-tr~;i..,

de t cc t i 1n.

Each line secti. 10 betw;;~;~n s t e.r i lOS [(.""pr·:':s,-,)yl~S h, :..:;11CK sec t i J[I r in whicha running train is p[1b?cted t.hr ouqh au t xna t i c sic~''"''.~_ i.ntc r Lock i nq , narne Ly t:hr:::single-linE bl)ck.

Thc:lreticallYr t.h-z wh xl ; lin2 O'v-.:mdl - 13)lU2 (;11.11<1 be lperot,,::d by n.~,:jllte

c mt.r ol. f r om th2 c ant r a l '!llSt Loca tvd in Owend o (t\i.~;uc;; 4G3~2)0 Howeve r , duet) ope r at.i lnal pr or.Loms with ATe and '·th,"; i:"n·'-1f-train detecti In; thesingle-line b11ck and , c mscquent.Ly , the ce>1tral t r a i n c mt r ol c ni Ld n rt heput int 1 service. 'I'r a t f i c is at pro-sent pr It,,,,ctod by the tel~"?ph lne bl ock ,whereas the s t e t i on s ar e lp.-;;.'rated in the "Loca I c mt.r ol " IDldp. (sec chapter403.5 flr mlre details).

4,3,4 P)W2r supply

SinceI oca t ed inexcepti )nally

t hr- Ti'laj )r i ty )fge)graDhicallv

th;;: 'rra'1sgab1rces'~ railwayis 11ab~:~ a r e as :::<Lcctc:ir>11

installatilnse~~'~rqy is

c.re)nly

E!ECA!CMU!42

Page 3~j

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E/ECA/CMU/42Page 40

supplied f r om the .nai ns , par t i cu LarLy at )f Owend)r NtJum q and Franc::~vil1e

stati,ns which are als) equipped with stand-by uicscl gr)upso

Five stati ms are permanently supplied with electrical energy f r om theOCTRA network from t) 2 x 125 kVA diesel gr)ups,3:i.ectrical energy for the)ther stati )OS is pr )vided by independant q r )UPS )f 2 x 20 and 2 x 40 kVArespectively.

Ph)t)v,1 taic energy had been utili zed t) f;;er:: certain oqu i.pmen t

"las part )f a stand-by r ad i o link for d Lspa t.cb i nq )n the Owend asecti )n. Since this r ad i o link went put Jut )f so rvLco , s xLa r energylonger used in the OCTRA network.

4.3.5 Operati,n and maintenanc~

whichB))ueis n)

Compared t) other African railway networks, the OCTRA network is sti 11very y ounq ,

Howeve r , in the field of b~lec ,mmunicati )OS, the t r ensmi ss Lon equipmentis made )f c 'mverrt i ona I t echn xl >9Y, namely anal )gu.,. This is due t) the factthat planning had already started in the seventies, shortly bef ore t he digitalt.echn oL>9Y was intr xiuced i nt o telec )mmunicati )ns.

Maintenance )f t r ansmi es i »i equipment is bo st; wit.h pr obLems arising t r om

the repeaters installed between stations. G2n~rally, the railway track passesthr)ugh the equat or i a l f)r~.?st z mes and th;::~(cf)r(? s o inaccessible by r oadsthat the maitenance gr)ups are c)mpell~d t) use dralsines f)r thsir transp)rtneeds. P)r this particular rea s m , the pe r i od )£ their activity is v(~ry

limited, since the train traffic must not be hampered for more than necessary,especially as it is a single-line.

Statistics sh)w that lightning causes numor JUS iJariiages t., th'2 equipment ~

It is expected that problem with t) b2 s)lve", during the year 19~'1 by thecompany "Les Cables de Li )n" which will install spe8ial pr )tecti )nG againstthe effects )f lightning. The cable pl,c','c), )n th.e sec xnd railway socti onwhich is equipped with quarters, is very sensible t) atID)spheric discharg~s~

As f)[ signalling r it is t) a large)f telephone block. On th0 other hand,equipment which are devoted t) signallingt) unexpected problems,

eX'.:.2n"": basr~;j )0 the classical me t h od

a GJrtsic1erable quantity )f m ode r nc ouLd D)t b2 put int) )perati,n due

Introducti)n )f the single-line block was prevented by the fact that theend-of-train detection equipment as well as for the automatic train controlworked in a way that "'as considered risky by the operator. It is supposedthat swinging magnets f or the end-of-train de t ec t Lon caused damages at them)ment )f passing the detect or s placed b<2tween th,? track such that the systemwas prevented f r nn working n )rmally. In add i t i 'm t) that, the aut »nat i c traincontrol were reported t) have initiated some emergency brakings although thesignal lights were green. This kind )f )bstacl" did not allow for t) pu t t i nqthe central control system at Owend) into service

E/ECA/CHU/42Page 41

It is h )wever estimated that tne use 1£ S );Jhisticated t eohnol )gi>2sdesigned tJ facilitate 5"1l))th running af t r ei ns , but .i.nv oLv i.nq highmaint~nance C)sts, is )nly vi~ble if the traffic is high and there is sh)rt~ge

staff. Pres e n t Ly , thes",> tW) f ac t or s are n)t r812v1.ilt within OCTRA and thatfact ha s led t » a cc r t.a i n ro Iuc t ance t ') )perat c~ t.b.. f1.b1V2 menti ')n.:::d cqu i.pmont ,

'I'his s )me rc.rs on i nq 80pliG-s t') th,:? q r »rn '"'L:lirl r ad i o sysc om whrcn hasa151 suffered f r o.n a ch r on i.c lack )f spa re j?2r::.s~ :8xJ>2rienC2 has sh own thatthe c )st-benefit rati ') 1",~.11 1n1}' be fav)r;-:b10 in :~ nigL-traffic n,;,tw1ck ~

Regul;3r supply )f qa s o i L is 2,.0 Imp ar t o nc t.?s.-; f)t tho? relev,int se rv i ces .

,\lurfler )US 1 )gistical )bst"1c12s may af f ec t requ.j..~,~ fLK,! supply f Jr ·t:.hc' d i c se Iq r oups which haV2 t) pr ov i de the electri."cl .-rc,y In tact, if thesignalling is n)t w)rking, train running ca~ ~3~~ys b2 m)d~ p)s~ibl.; pr)vid~d

that it is ·d)ne ceuc i )usly~ H)w,~v.'?rr t raf f i.« <·7)ul;.'"; be seri ousIy diRturhedwith)ut tbe 1 )cal tcleph)ny (It ~,!)uld be 02C,"s5.Jry t) use t.h,:,: SSB cadi).

c}j,th regard t1 t:hE: r0;::~1 Yk;>eds and Le v.:'; y~- tr('\. :"'\.119 )f the m:,!i'1t>..:;n.3n~0

staff" the p ower suppi.y cqup:..ment; 'p'nntb:: ~l/ t hc 'IT?lnsgab)D r a i Iwey s isg~~j)8rally t)) s oph i s t i ca t ed , A s i mpLi f i ce t Lon Jf (::':ruipm(~nt f or the C;)DL.r)] )ft he gr )UPS w)uld facilitate ma i nt.onance w)rke sm') c )nsegu(::nt1.t sh »r t endelays. This is nec;.~ssa[i f or fau Lt; c Laar Ln., (2cg qr oups wi t b out au t oma t i.cstart, less electr)nic circuits, .•. ).

Thelab nat n¥

SET (Signalling, energy, teleC)llp'lunicSiti »ns ) o i v i s i onwhich is in c narqe )f maintaining r e Levarrt equipm8nt.

has a

~,3.6 Quality)t 52rvice

Sev0ral factJrs influencet e l.ec ommun i.cat i »ns , s i qnnLl.Lnc and

the qualityr )w~r supply"

service with

Acc)rding t) s·i:>:tist.1CS, 78 incidents h'2~;~; ",~:pJrted t) hflVC )Ccurredc once r n.i nq the trans:nissi)n equipm;~nt du r i r-q -l::;h: f5rst half Jf 1990. Tbcde f i c i enc i e s held been p?rtly caused by t he m.)L,dal iesc'H, but they wer.' "Is)c:ue tJ cuts and f au lcs in th\? c rex is I. ~,'~bl;', 't'ho -:..~·-~'::1:..:: )D t~,,: first soc c i on ,which had bBl..::n put at 60 em unde r the' t',allast wc.!s cut six times during theab ove pe r i od , due tJ subs rdonc-.s )f t ho ~,l·)tf)::~n" 'i'h i s pr ob l om c ou Ld beav)ided )r th~ sec,nd.s2C~i)n beC0l1S"- its rl'1tf)~" is 8)r'~ stahle.

Since sign:>J ll.i'g IS re s t r i.c t.ed t) T~k}ll-t(:i.,~c: t,:?chniquessignals in the st~tiJns, te10ph)ne bl)ck b2tw0:n st2ti)ns), therepr )blem c 'mce r n i nq Uh:"i r qu,::~,li ty )f service.

(o Lcc t r i.cn Iis n i :;P"I;j J[

E,ECiJCUJ/-i2Page 42

4.3 7 Summary

AlthJugh the r~ilw~y netwJrkc ms i.de r abl e t eLec »nmun i ce r i. »ns andprlblems.

If G::=,;I:»)I)

s i qnaLl irv:i:' very y ounq , t he r; a r eJr"cr;cti In'11 ;:-.nu m;:d.nt0nance

With r eqa r d t J t e Lec »nmuruce t i lOS, an a L)gu JUS t.ronsmi s s i JO systems a roused , because is a 11ng de13y betveen the beqinning 1f p r Jject planning t J itsirnplementati In. It sh ourd bt., unde r Li qned i t.hat; 'Chis technJllgy is n rt bad 1[

inadequate in itself. But the Jf ar2 installatiJn rUP2aters 1n the lin~side

between s t at i JOS, a Lt.h iuqh thJSE places ;-.(,? 01t 2ccBssib12 by [J-9d, is ac1nsiderablp disadv~nt~ge tJ that system.

The intr xlucti 10 Jf S 1phisticated t.O!chniqut~s sh ou l.d be preceded by asystematic s t af f t ra i n i nq , the t ype tJ be )r{~)3nis2df f or tl21eclmmunicr:lti1npe r s xnne L ", the multiplex equipment f r om Oc'nber '.990 t) July E'91 by ~n

e nqi nee r fr 1m the c );nneny CJ':".' ALCATELo

4.4 Tunisia

E!ECA!CMU!42Page 43

4.4.1 The national railway network

4.4.2 Telecommunications

4.4.3 Signalling

4.4.4 Powcr supply

4.4.5 0 & M

4.4.6 Quality of scrvicc

4.4.7 Summary

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\-.lith a t o ta l Lcrig t h of 2,200 km of ma i n lines plus about; 100 stationsand 160 wav r s t a t i on s , the Na t i oria l Ra i l wav s Compa r-v of Tun i s a (SNCFT) servesthe rnos t i mpo r tarvt r owns ;:nd p l.-:tCCSI n the c ount r v . The narrow-gauge nc t workr i rn ) is situated in the South whc r c a s the so c a l Lc d "normal-gauge'; (1.43 m)network, hav i nv n t o t a l lc~gt"h of .1~(;·;t 400 km , cover." the Nothern part of the

countr-y.

Some 29 mill ion pas s cngc rs were t r ans po r t co in L:;:3:; wi t h i n the t wo majortraffic categories, namely, the transport on long-distance lines and thesuburban t r a f f i c , The total traffic volume reached 718 million pa s scng c r s-rkrn ,

The rolling s t ock Li s at present composed of 190 locomotives, 5,300wagons and 200 coaches. All the tractive performances arc diesel operated. Twoelectrification p r o j cc ts currently are bc i ng implemented on two l i no slhav i ng -'1

total length of 65 km , A project to electrify a certain number of suburbanlines t s also under -vav .

As r cga rd s goods transport,during the ahovc period, 2 billion

SNCFT has,tons-kl11.

the t r ans po r t cd 11 million tons

The total number of staff is 9,200.

Currently, one s ubu rban line is being provided 'I~T,.th .:t t h i r d track, t ha t

will operate in both d i r cc t i ons . l\llnormaliz:ltion.;; i s under execution aimed atgradiafif'iu r cp Lac i ng the na r xow -gaugc tracks by -to rmoJ gauges. At t b i s moment,the first two phases, namely 'i'un i s - Sou s s c .md Sous .s c - Sf3X arc undo r way.The construction of the Sfax Tripolis (Libyol l i nc wi 11 constitute animportant future expa.nsion project.

Figure 4.4.1. s hovs the conf i gu rn t i on of the SNCFT nct.vo rk ,


Cur-rc nt Lv , the SNCFT t o l oc ornmuni c a t i on ~)ct~'\10r" 1S bc i nc digit.ized andthe process is supposed to bc completed by the end of 1990.

Undcrn the project, 6 stations ~t regional. directorates will be equippedwith private digital exc11ungcs (JISTEL, Jcumont/Schncider) with initialcnpacities ranging from 112 to 800 lines. All suhsc~ibcrs in t'le ~llrrounding

stations will be connected to their respective exchanges 3S distantsub.cribers.

The telephone exchanges arc interconnected hy peM link. (2 Mbit /seel aspart of the t r ansmi 55 ion network joint ly operated wi th the pub lietelecommunications network, Transmission is ensured partly hy microwave linksand partly by cable links. Besides the high-frequency links, SNCFT a I so haslow-frequency mainly used for such services as, dispatching, selective calls)station-to-station links, and 3utoffiatic hlock.

Data transmission which is at p r cscnt; operated on leased circuits, willbe integrated into the digital transmission nct~Jur~ and therefore coristitute asubnetwork of the public nc t work , Remote da t a procc s s ir«; via t c l cc o-nrnun i c at i onlinks is being used for personnel administ~3ti0n, disposal of wag(,ns, ticketsales, and in the near future will be used fllr rcscrvatiC)PF.

E/ECA/CMU/42Page 46

There is no ground-train radio for the -nomcn t ,

planned for the whole n e t wo r k , according to the mcr~i.t';:n

4.4.3 Signalling

but its introduction isterm p13n (8th plan).

The Tunis Sfax line, the entire Southern nc twork 3S wcl} a s somes tat i ons in the North arc equipped wi t h s i gna i l i ug systems.

Apart from only c c rt a in 1 i nc s I.TI

signalling 15 still done manua l Iv , mos t

Tunisia GTe electrical (mainly suppliedWestinghouse) .

t'-1£: Ccn t c r of the country whcrcc f th,:, s i gnol l i na systems used r n

by the Italian comp3ny Wabco

The Tunis station and some o t hc r important stations a rc equipped withflcxihlc intcrlockjng systems. Control centres of this type have lightingpanels and control tnb l c s t-1ith bu t t un s for selecting itineraries, Thesystem's flcxibi,lity allows it tl) control itineraries hv fractions.

The control of s i gna l s and po i n t sgcugrapllical circuitry relay c3hins. Thisfor complete itineraries.

in othertechnique,

stations ispush-hut ton

done throughcontrol desks

In the case of a single-line l s i.g o a t I i ng ho s to he adap t cd for hathdirections, and the runn i ng t ra i.n is p r o t c.c t c.u by t b c single-line block. Assoon as ;'1 train has been dispatched, no other tr3ffi,c shull be 31lowed in theoccupied block sectiono After the liberation of the section which is ensuredby the c nd r-o f r-t r a i n detector it is now po s si.b l o , to .rcquo sc for dispatching,another t r a i n in one direction or the o t hc r, E.-t;Vcr.1 1 si rig l c-'? i ne s a r cequipped \.1it1, s i ng l c-r l inc block systems, uowcvc r- Of' one of these lines, theequipment has never been opc rs t cd Since its in.s to l l.a t i on due to the reasonsgiven in paragraph 484.50

Since the s i ng l c-r li nc b l ocv s i gna l l i nc C3nTlOt entirely exclude humanerrors, systems for automatic train control (I\.T-::::) a r c opc r a t c d as anadd it ion.1l S3 fcty measure. Transponders for the [,~'to'nati c t r a i n contra 1 arcinstalled b c t wcc n the t r-nc k s , next to the on tv-mc c and exit signals, foroc rbo.t rd repetition of i nf o rrna t ion on the po s iti or- of signals. An emergencybraking will be i n i t i at cd if ,:"In i''1PC·,~.1tivc ~~ign:'1.. i.nd i.. c a t i ng "section c Lo s cd"

wou l d not have been respected bv thc t r a i n driver (Figure 4.402), Currently,not all the ATe equipment installed on board trains running on s i ng l c r l i ncroutes is operated. The working of ATC is d c s c r i.bcd i.o pa r ag r a ph 3.2.

On doub l.c-r Li nc routes, .'lutomatic interlocking constitutes the key systemof signalling (for. dctailed description plcasc rcfcr to paragraph 3.2). Allsignals, including those of level crossings, .ar c automatically set QY thetrains running from one block section to another. 'Lr a i.n s running on routesyrith automatic interlocking arc not yet provided with ATe systems.Howcver,its installation is anticipated in futurc projects.

With 3 view to i nc rcas i ng d i spa t ch i ng efficiency, a project for theestablishment of ccntralized traffic central (eTC) 18 going on. The CTC willallow for the remote control of the t r.af I i c ovc: ior~~ distances. One of thesystems is being installed on .1. suburhan line,

Fiqu!.".f'_.,:l. 4 ~2: Silt j.n~f of t rnck s .i.ndesert area

Signnl at station I'nl:','h'i t.h Loa.con of I\TC

E/ECA/CMU/42Page 48

Hithin the framework of the above "1C'ntioncd medium-term plan, somelight-traffic lines will be equipped with radio signalling. Rad i o s i gna I l i ngis II method that f ac iLi t atcs train running bv me-ins of coded messages wh i c harc t ransmi t t cd from a control centre to the t rii n drivers. These messages arcsent only after all satety conditions hav i ng been vc r i f i cd automatically.They reflect the prescnt situation of line operation and protect the trains inaccordance w i t h to the principles of signalling. (for more dc t a i l s secparagraph 3.2).

4.4.4 Power supply

The SNCFT attaches much i.mpo r t anc c to of power supply .w i t h regard tomeasures that have been taken to gua r ante c permanent energy supply for theequipment. Batteries as well as diesel groups for continuous running arcdesigned to avoid any power cuts) even ()f a very short duration (interruptiontime is p r a t i.c a l Lv zero). Photovoltaic energy is so far not in usc.


On one of the. Jines having been c qu i ppc-L'wi t h modern signalling systems,namely line no. 21, SNCFT has to apply the ancient mct hod s s i.nc c the cqu i pmcntinstalled ahout five years ago c anno t be opc r a t cd , This r a i Iwav line vb i chserves for the t r anspo r t of phos pha t c passes t h r oug: desert a rca s 1 and thcconsequent investments f o r povc r supply in stations heavy ~ But 31 though energygives considerable problems, these can a Iwav s he solved in line witheconomical and technical considerations. HO"JCVC\·, siy,:lollin2: on the line isseriously hampered by permanent s i l t i ng s wo i.c u , du r i ng the r a i n s , provokeshort-circuits between the tracks and, c onscouc nr Ly , false indications on thelighting panels (Figure 4,4.3), The s i l.t i ng s also hsturb the normal wo rki ngof point machines nnd the facing of the point leafs.

Even on some other lines, ;",here s i gna l Lii.g s v stcms 31'<: operated, theproblem of silting provokes d i s t u rbanc c s of the t rnc k-rc i rcu i t s during t hcrainy season. The expansIon of tracks due to hc~t may cause electricalcontact8 hetween line sections which normally arc insulated one from theother. This p r ob l crn cou l d be solved bv a bc t t c r maintenance of the insulatingclements.

The functional division for the maintenance of telecommunications andsignalling installations, which was created two YC3rs ago, is responsible fordeveloping methodf; for improving operation and maintenance by mcans ofpunctual and qualitative follow-ups.

This division has prepared directions to guide operators with the 31m ofreducing delays t oany kind of interventions, That objective has been partlyachieved by the creation of a l abornt ory in '.,hieh about 90 per cent of theelectronic circuits can be r cparcd locally. Efforts to obtai.n autonomy willbe intensified through the implementation of an c l c t romcchan i c a I workshopwhere, among other things) motor coils ~.,il] he r cwi ndcd , Import action ofsome other componcnt s which can be produced locally vi 11 be reducedsubsequently. Certain activities will also be earroed pit tp eneure periodicalsupply of spare parts with a view to always having a minimum level avail~ble.

From 1991 on, a national railways school shouldtraining needs in tclccommunicationR nnd signalling) among

be ab l cothers.

to satisfy

E/ECA/C/1U/42Page 49

4.4.6 Quality of SerVIce

In Tunisia like else where, the introduction of nC-":J technics has to becarried out together with sensilization of th~ rclcv2nt personnel, because itoften implies change of habit. Only if thc new sy.t0ms arc fully accepted bythe staff in charge. of operation -md maintenance and if the necessary care istaken, can one take advant agc of all f c a t u r e s offered by modern sy s t cms ,Failure to take these precautions wou l d not only r cduc c safety levels) butwould also do considerable damage.

SNCFT has registered frequent demolitions o f t r ans pondc r s for ATC aswell as the c nd r-o f r-t vn i n detectors by swi ng i nr- objects leading to questionableworking of the resp0ctive safety sytems.

To cmcdy these deficiencies, delivery ofshould be subject to submission of damage reportsof the incident and the measures adoptcd.

4.4.7 Summary

stuck of major spare partsindicating all circumst.:lnccs

The r a i Iway ne t work of Tun is i a is e xpand ing rapidly,construction of new lines, standardization of na r r ow-gaugcconstruction of third tracks on heavy-traffic lines_

withlines

theand

Telecommunications 3T'e curr.ently being modernized to suit present needs,mainly by digitization of exchanges as well as the mi c rowavo links including adigital data transmission network.

Basically, s i gnc ll i ng is ending a Long with cvo l ot i ons of the nc t vork andtechnology. The most important part of the ra i l.w.ry network has already beenequipped with c Icc r r i c a l systems. However, the si~D.!lll:ing cquipment cannotalways be used to full capacity, due to technical .a:i.d operational problems,namely frequent destruction of ATC transponders aad end-of-train detectors byswinging objects, in su f f i c icnt i nsu l a t i on be tween the various track sectionsand silting of tracks.

Although electrical signalling systems arc oractically error-fr0e withinthemselves, they cannot exclude human errors if the t r af f ic is not protectedby additional measures, namely ATC, ground-train rad i o , or radio signallingfor light traffic. The cx i s t i ng plans ant i.c i pz.t c introduction of hack-upsignalling systems.

SNCFT attaches great 'cmportanc0 to energy suppJv wb i ch requires heavyinvestments, especially in isolated areas and also high operating costs forthe usc of pc rrnancn t Ly running diesel g r oups . Solar energy :i 5 not yet used.

Efforts a i mcd at inc rc a s i ng au t ouomv in the production of components andspare parts as well as organisation of f()!]ow-ups arc examplary.

The company is conscious of theon the quality of signalling servicelevel of safety in train running.

above-mentioned weaknesses which affectIn the field of which may reduce the

E/ECA/CMU/42Page 50

4.5 Z:lire

4.5.1 The n:ltional railw:lY network


4.5.3 Sign:llling

4.5.4 Power supply

4.5.50&M

4.5.6 Quality of service

4.5.7 Summary

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Telecommunications and Signallingon Arrican Railways

n(L\!f~_4~~CfMK Line (OIlATRAl

E/ECA/Cl"U/42Page 52


In 1974, monopoly for the opc rst i on of ~,j_J. ra i Iwny lines 1D Zaire ~""as

conceded to the Na t i.oria I Ra i l wav s Company o f Zn i r-c (SNCZ) which contracted,the management of the Na t ad i - t<.inshas3 1inc (r;pu/) to the National TransportAuthority (ONATRA).

For practical reasons, this study is confined to the equipment operatedby ONATRA, with regard to diagnosis on telecommunications :Ind signalling.

(i) SNCZ

SNCZ is subdivided into 4 operational regions, namely, the South, theEast, the Centre and the North, 3 of which arc interconnected.

The total length ofgauges: 1.067 m (80 per cent

the main lines isof the total), 1060

abou t /.,500 krn ,

m and 0.60 m.There ::I.rc 3

As for the rolling stock, the company ""3.5 1 ~~8 r031n line locomotives103 of them have dicscJ t r ac t i on , wh i l c the o t bc r s electrical. Theiravailability is presently about 45 per cent. T~'IC nurubc r of commercia] coachesis about 300. There are:115o 103 service cO;;,ChC5 The total number: of wagons5,282, of which 4,774 arc commercial. In add it i on to this are about 1,000wagons belonging external oper0tors.

In 1989,transport units

the total(TU), the

volume of c ommcr c i o lpassenger .'Jnd luggage

r r af f ic reached 1,854 hilliontr.ffic was 197 hillion TU.

The numher of staff about 20,000.

(i]) ONATRA

The r a i Lway traffic of ONATRA is composed of two parts, -iarnc l y , theMatadi - Kinshasa line (CFMK) and the urh.n traffic 1n the Kinshasn area.

The total length of the network lS 766 krn , of wb i ch 366 km consti tutethe main line. While the Kinshasa area is provided ,.lith doub Lc-t Li nc routes,the long-distance line is mainly a single-track line having a gauge of 1.067 m(Figure 4.5.]).

Thelines, 99wagons.

rolling stock IS

coaches and 2,298composed of 24 diesel

wagons, of which 2,243locomotives for the main

arc .:l1l-purposc commercial

The number of complete trains was 10.910 (all ki.nd of trains arc mergedin this figure). In 1989, 630 of them were pas scrigc r t r s i ns , The number ofpassengers during that v ee r was 819,566 and tbe300ds traffic 1,930,342 tons,respectively or344,474,677 tons-km.

In order to increase the tonnage and numlc r of pc s s c ngc r s , D study wasundertaken in 1988 on ways to modernize s i gn a l l i ng and telecommunications ofthe CFMK line, whcreas a project on the mode roi z a t Lon of signalling in theKinshasa area is already being cxectltcd and expected to be cumpJ.ctcd by March1991.

E/ECil/CMU/42Page 53

405.2 Tclccommunic0tions

The telephone nc t vo rk of the CFMK line includes exchanges In Kinshasa,Matadi, Lufu Toto and Hbanz a-r Ngungu to which a t o t a l of 1,200 lines a r cconnected. The electromechanical exchange in x i ns ha s c (Pcnt orna t 1000 CT, Bell)is insufficient wi t h r c g a rd to t raf f i c capacity. S'i nc c - there is .:I shortatc 'ofcircuits inter-urban c ommuni.c a t ionsia r c opc r a t r-d ~'.1.'1E;_~311y.

A smnl1 digital exchangeinstalled in the Kin sbas a a r ea .signalling.

for localIt is part

t cLc p: ono communication h a s been(;f the ~rojcct on mod~rnization of

A avmmct ri.c a l cable composed of two s cc t ions , whi.c h \.'crc laid in 1956and 1976 respectively, c oris t i t ut e s t 11C transmission support" a I eng the l i nc ,The first cable section is opc r a t cd j o i nt l v 'toj'] th the H,::tional. Posts andTelecommunications Authority (OI'1PTZ). Inadcou-ic i cs , c s pcc i a l Ly i ns oia t i on .donot 3.1Jow for the usc of the mul.t i p l cx c cu ionco t 'i,;hich l,J3S 'ins t a Ll cd in 1977.For this reason, the cable I i nl- c annc t s3t.;'Jf/ ,1.11 needs for circuits fordispatching, station-to-st3.tion links, ground-tr3in rndio, signalling 3ndadministration.

The ground-train radio i n s t a Ll.cd an 1977 (j-o t o ro l c ) facilitates linksbe tween the dispatchers tn Ki nshas a and ;13tadi on one side and the t ea i.ndrivers on the other s i..dc . It wor k s in the 160 MHz range, T~,Jo loaded quartersin the above cable link constitute t~e nCCeSS3YV ~ransmission SUpp(lrt fur thesystem w't i cb serves 11 fixed units. Abou t 30 locomotives arc cqu i pped w i t bradio units, but numerous engines runn without a radio on huard.

4.5.3 Signnlling

Electrical signalling with centralized controi has operated .s i nc c 1956over .1 distance of 90 km on the CF~'n{ 1inc, The system serves 10 s rn r i on s , 9 ofwh i ch arc operated by r omo t.c control f r om the c cr tro I centre located inKinsh3sa. Each station J.S eqllipped with 1 c0trnncc sign31s, with dist~nt

signals and 4 to 6 cx~t sign3.1s, dCDcndj.ng on t~cir ~nlPQrt3n~c,~ This kind ofsignalling alluws [or transitting thruugh the st3tions on thc dircc,t line.The d i spa t c hc r l ocn t cd in Ki rvsh a s a has 3 c ont ro I dcs': a rl owi ng him t o c on t r o Ithe points and signals arid to 1)( 3.W:lre, at tn.Y ~J1Jlf'., of the ac t ua l situationof the c qu i pmcnt; .'IS well .'IS the positions of !':',r, t r m.ns . The. remote controlequipment is c l cc r r ornccn.m i c a l and wor-ks bv mC3PS of messages t.1h i c :l 3recomposed of l rr-Lmpu Ls i on-c odc s transmitted via an uu ioudcd P21!: carried in t.h ctelephone cable. The control may bc executed c it.hc.o- xo the "jr i nc r a r y -iodc"when points and s igo a Ls -i r c c on t r o l Lcd f r-om r t.c c cntrn l rust, ':.1Y In t b r

"manoeuvre modc " whc n they a r c c on t '"T t Lod 1OC.3:':.

The traffic bc t cccn the s t a t i o o s is pcoc oc ccd hy t~lC singlc-}jnc block.Originally, the bluck sections were clc~red bv mcan~ of end of-traindetectors. Today) the ] inc is no longer eql'<.?PCQ ~,!it'", t ha t system morc , andclearance is done manua l Ly hy reset sticks w~ich for that particular purposearc availahle in the stations. ATC is 3150 not operated any longer.

withthis

Most of the stationsautomatic light signalskind on thc line.

withand

c lcc t r i c a I s i gr-.r ll i ng have level crossingsthere .t r c t vo ao d i t i ona l level crossings of

E/ECA/CHU/42Page 54

The other stations have mechanical. signalling ~ithout

interlocking, whereas the b10ck sections arc Plot~ctcd hytoken systems (Ikhh-Thomson).

the possibility ofmeans of electrical

A project on the modc rn i z a t i on of signalling is curcntly go i ng on in theKi n sb a s a a r ca . A flexihle intcr1.ockingc:ystcrr· ('''..ns 801, Sjcrnc n s ) wi t h centralcontrol i.e; part of the project. Its implementation IS scheduled for March1991, but onc part of the equipment is a l vc adv bl opc r a t i on . \-lithin theframework of that project, all s t n t i ons will receive control desks, so thattheir equipment can he controlled locally. To allow fOT the usc oft r ack-c i r c o i t s , the project includes replacement of mcta l Li c sleepers byconcrete ones on the main tracks.

Clearance of block sections w i l I be done :)Y 'TIc.:-tns of four ,1xle-countcrsystems (sec also paragrap~ 3.2 fc)r 3 detailed dcsc;ril)tion). The 3dvantagc ofthis technique, is that it o lso <111m...' 8 for opc r.vt inp on old with-metallicsleepers. The sleepers c f r:1H.~ shunting Linc s -;~'-iC -ot vet been replaced Fat"economic reasons. In o rd c r to i r-d i ca t c the apl:;~;c::":anc(: of a t rai n at a signal J

the tracks arc provided with anuunccmcnt cunt3ct~.

4.5.4 Power supply

Eleven stations a l ong the L'13tadi - Ki rs h.i s a tine arc povc rcd from themains, whereas 10 .rrc equipped wi.t h diesel g-'(OUrS of 25 or -34 kVA c ach . Sevenof them arc mainly devoted to feeding the c Lc c r r i c a I s i gna l l i ng equipment.Each of t hos c stations has t"-·70 g r oup s , and one ou t. of the two is 't-T(,i.kingpermanently, a numb c r of equipment is not bac kc d by batteries. f o r ex .....mpl.c thepoint machines, and the si.gnal lights.

The fixed units of the g r ound-it r a i n radio h.?vc <J power consumption of 60W each. They arc fed either fro~ the m3ins,dicscl groups or so13r equipment.

The solar generators were i ns t a l l cd an 1987 in 5 s t a t i ons to feed t I1C

ground-train radio installations 02 V) and the repeaters of thetelecommunications cab l.c (24 V). One of the t-.-r. d i cs c l ?crcr.Jtors which wasformerly installed in those stations, were later removed and t bc other oneworks only at night for lighting. (Figures 4.502 and 4.5.3).

The telephone equipment in the other s ta t i ons is fed by l oc c l ba t t c r i c s .

J~i~,CA/CMU/42

Page 55

Figure 4.5.2: Total view of the MalangaStation with solar panels(left side of passengerbuilding)

)~

j

'/i

~fFigure 4.5.3: Detailed viewAsolar

panels with antennafor ground-trainradio

E/ECA/CHU/4 2Page 56


Generally speaking, operation and mai.n t cnanc c work s arc bcmpc r od hy lackof spare parts and transportation difficulties.

All the lcve 1 of telecommunications there arc marry problems w i.t h regardto 0 & M, mainly c auscd by saturated c xchangcs , sho r t agc of circuits and poorqual i ty of transmission support on the cab l c , 'T";lC;:"C arc frequent breakdowns,and ONATRA is at prescnt looking for funds to rcplrrcc the ohsolete c(lu-tpmcnt.

The ground-train radio is not equipped with selective calla way t.hn t at each call from the d i s pa t chcr , one half oftransmits and this has 3.TI impact not only on the cconorm cequipment, but also on its energy consumption"

f ac i li t i c s inthe stationslife of the

The equipment for electrical signalling ,,'1it\ centralizcd control on theCFMK line is virtually worn out. Its function is also hampered by the badcondition of the c ab l o , Consequently, trains t r ar.s i t t i ng the respective linesections often find c l o scd signals caused by failures Q The main reason forthose failures is the bad condition of the track-circuits: polluted ballast,broken fish plates and crashed insulation profiles.

The c nd-to f t-t r a i.n detection is not opc r a t cd any more, due mainly to lackof spare parts for the repair of defective equipment D ATC is also out ofservice, apparently for the same reasons. Emcrgc~cy hrakings h~ve beenreported although the lights were green.

The electric token systems In the stations without s i.gnn Lt i ng orealready dilapidated) although they still conveniently render. some s c rv i c c ,owing to their r obus t no s s , in the event of a breakdown of this system, thestation master usually tries in conrac. the d is t-a t c hc r to communicate thenumber of the clearance bu Ll c t i n given to the r.r3:i.n driver. Ncvc r t r-c l c s s , theprescnt safety device is good, since rhc nurnocr uf accidents in stationswithout signalling is low, but t b c absence of modern equipment requires a JOll

speed, should be observed.

A b i La t c r-a l Cc rmano-tZn i r i.nn project is prc scnt Ly go 1.o.g on r n theKinshasa area directed to the modcrniz3tio~ ()f signalling. Part of theinstallation 15 alre3~Y working. Howevcr, definite ~esults on the operationarc not yet avu i l ab lc , Alt hough the proj c c t r::O'lCC{'nS urban tra f f i c , thc othertraffic categories (long distance, sbun c i ng ) ,,,:i1.1 benefit from it. it hasbeen noted that Slltluting delays h3ve dccrC3sed.

The new installations incltldc centralize~ contro~ of all stations 1n t\lC

Kinshasa area. Butalways be necessarythe shunting linesdispatChing centre.

itIn

arc

should be noted, that ;1 certain number of staff willthose stations, since there arc still manual points andnot equipped with f ac i l i t i cs for c ommun ic a t i.cn wi t h the

Z/ECA/CMU/42Page 57

The project comprises equipment for the au r oma t i.c opc r a t i on of levelcrossings {f l a sb l i gh t s and s cm i e-ba r r i c r s ) . Howcvc r , the first t r i.n l s haveshowncd that closing pc r i od s wc t-c very long, mak i ng impatient motorcar driversto pass the crossings when the lights were red, For safety rC<3.S0ns, it hastherefore been decided that of level crossings wi Ll still be protected byguardsmen for an unlimited period of time

Energy supply from the mains and d i o sc I groups arc likely to releaseunstable voltages. On the othe r hand" ,<;t..1tionsfcd by solar gcnc r ato r s do notgive any problems. During the 3 YC3,rs: of their 'ins t a Lla t i.on only one breakdownhas occurred, o3mcly, on a solar panel c:1uscdby lightning.

Energy supply byAuthority. that by solar

4.5.6 Qnality of service

diesel group~ c()nstitutcsenergy' is very cncourac i ng ,

heavy burden for the

In spite of t hc c ompc t cnc c of and efforts \<)~lJe by the maintenances c rv i c c s , the quality of of telecqmmunications nne ragflallit1g service is stillmediocre. some improvement -i s an t ic i pa t cd after the completion of the r a i Lwavproject in the Ki n s t-a s a area and the 'impl cmcn t a t ion of 3 p r o j cc t on modernizeof sisnalling on thc·CFMK li~e~

It should howcvc-rvbc j undc r Lincd t ha t the lilcll-tricrl s i gns l Li ng systems(electric token) still render an acceptable qua l iLy of service. On the otherhand, abscnco of cnd-ro f-rer-a i n magnets reduces safety in the section havingc Lcc t r i caI signalling with remote control nevertheless, the slowness is hardlyfelt, since tr3ffic on this line is rclanivcly low.

4.5.7 Snmmary

The telecommunications and signalling equipment operated by ONATRA arereached no longer. economically viable. In the meantime, a project for theirmodernization is going on in the Ki.n s h.i s a , It wi l l be completed by March1991.. A study on the needs of the CF~1K line has been carried out. It proposesthe introduction" of s i.mpl i f i cd. s i gnn l Li ng , digi-tal switching and transmissionsystems as well as solar energy for gcoz r apb i ca l Iv isolated stations.

The most ancientsatisfy the basic needs ~

relatively low.

signalling techniotle (clcctrjcal token)as it is s t i Ll, op c r-o t a on a L, provide t hnt;

can s t i 11traffic is

Certain moderntrain control) arc out

signaJling systems (c~rt-of-trnin detcctionj

of order due to a 13c~ of spa~c pnrts.all t oma t ic

The ground-train r ad i o tvhich 15 c c.nc c i vcd in .3. simplified configuration(usc of only one frequency) is considered to he a useful to the safety oftrain running. This system, installed in 1977, is still works s a t i s f ac t o r i l.y ,

Major voltage fluctuations may C3USC d ama;c to f,lcctric,'11 'i n s t a l La t i ons ,specifically in especially circuits.

Feeding ground-train r ad i.o and rCpc3tC"CS 1~ isolated s t a t i.on s wi t h solarenergy has given good results.

E/EX:A/CMU/42Page 58

5. SUMMARY OF THE PERCEPTIONS

5.1 General

(i) The services responsible for operation and maintenance oftelecommunications as well as signalling are not alwaysadequately represented hierarchically within the railwaycompanies. Sometimes, they are only attached as annexesto other services, departments or divisions for instance,the permanent way. Sometimes, they are organized indistricts under different sections within one company. Inother words, these services represent the "poor relatives"of the railways.

(ii) The services very often suffer from chronic lack of qualifiedstaff, spare parts and tools which are necessary for propercorrective rather than preventive maintenance.

(iii) There is reluctance to repair defective equipment.Apparently, this is due to the fact that the results obtainedby operating these installations fall short of expectations,particularly as regards time savings, increase in the trafficvolume and reduction of the numher of staff.

(tv) The damage caused by lightnings is considerable. This issometimes due to absence or inadequate groundings. In someareas of Africa, special protection against the effect oflightning are necessqry. In other words, the standardsapplied in the industrialized countries may not satisfythe needs of African countries.

(v) Railway companies normally have laboratories for the repairof all equipment at their disposal. However, their capacitiesare sometimes limited by lack of spare parts, professionalcomponents and measuring instruments which is partly dueto a very large diversification of equipment suppliers.

(vi) Although the number of staff is sometimes excessive, thereis a general lack of qualified personnel, due mainly tobetter salaries in private companies.

5.2 Telecommunications

As regards switching, there areand digital systems which;satisfactorily.

electromechanical, electronicin principle, are working

(ii) In the domain of transmission, several problems of diverseorigines are known, namely:

E/ECA/CHU/4 2Page 59

(a) i.L1terrupt..i.vfJ. or theft uf copper wires,

(b) interruption of coaxial cables (cavinro in of platforms),

(c) damage of electronic circuits in mUltiplex systems(lack of spare parts, ••• ),

SSE radios serve as back-up links in dispatching and stationto-station links in case of breakdown of the basic network.

(iv)

(v)

The ground-train radio is not always operated 100 percent,due to lack of spare parts.

Transmission networks may comprise circuits which are leaseifrom the public telecommunication aiministrations.

5.3 Signallinp;

(i) There are systems for signalling between usually non-electric,stations of a very elementary technology, particularly onsingle-line routes having 10'1" traffic, which may still beaiequate (tokens, telephone block ••• J. This is alsovaluable, for mechanical signalling in stations.

(11) Moiernization of signallinp; was not always preceeiei byrehabilitation of the permanent way, resultinp; in no increasein the traffic volume.

(iii )

(iv)

Correct operation of optical control panels ani relateis i13,·".1 'i '.1'.: sy' 'C''CS ( sin,o;le"line block, automatic blocksystems, CTC, remote corrtr-o.l ) is very touchy ani vulnerableto faults in the way circuits. The faults may be traceieither to maintenance level (lack of insulation betweentrack lines, particularly causei by breaks of the wooienfish-plates or their replacement by metallic plates as wellas by expansion of tracks iue to heat). It can also becausei y ievasting environmental effects as permanent siltingup of tracks, thus causing short-circuits between the tracks.The Figure 5.1 shows an anti-silting protection in Tunisia.

The correct operation of the eni-of--train ietection. issometimes hamperei either by the swinging of the tail unitsor by the iestruction of the responiers causei by pendf.ng'objects (SEE Figure 5.2).

The axle-counter has the aivantage of not requiring anytrain-borne equipment. It is also iniepenient of traincircuits, especially insulatEd .tracks. Therefore, it maybe cOIU3Uerei a6 an alternative to the eni-of-train ietection.

r:!ECA!Cl1H!!j2Page 60

Protectioll agail'st siltinq(Tunis'ia}

-,.....

Figure 5.3: Beacon of ATe

Figure 5.4: Manuel .el . poi.n t; withectr1cal .1nterlock'lng

E/ECA/CMU/42Page 62 .....

(vi)

(vii)

(viii )

(ix)

The operation of automatic train control may be hampereiQy iestructio~ of the responiers (Figure 5.3). In one case,it was no longer operatei because it promptei emergencybreakings when the signal lights were green.

Raiio-siPjIlallinp; (raiio electronic token block) is a moiernsolution to the problem of signalling for trains on lightlyusei linea which io not require signals, apparatus, boxesor cables on the tracksiie. This technique is reporteito be operatei Qy Botswana Railways, However, that countryis not among those visitei in the framework of this stuiy.

Concerning iouble-line routes with heavy traffic, automaticinterlocking is operatei.

The single-line block operates euccesarul.Iy on single-lineroutes consiierable traffic flow.

(x) Automatic train control (ATC) as well as eni-of-trainietection are important for increasing safety.

(xi) Electrical or manual points with electrical interlocking(Figure 5.4) are working satisfactori:q, except when silteiup in iesert areas.

5.3 Power supply

Although electric power is on.Iy except.Lona.Lly suppliei fromthe mains, solar en."rgy is rare:q util1zei.

( ii)

(iv)

Basical:q, the few installations for photovoltaic energyare working satisfactorily. There are some weak pointsin the regulators (ieconnection of batteries in case ofhigh voltage or to avoii ieep iischarges).

The operation of t.e.Lecomnnmtcat.tone ani signalling iepenislarge:q on power suppliei Qy iiesel generator groups. Thiskin'! of equipment has a hif",h reliability, provi'iei thatmaintenance is carriei out regular:q. However, the regularfuel supp:q reqcirement may cause logistical problems.

In some cases, the control equipment for iiesel generatorgroups is more sophisticatei than necessary, resulting inexorbitant investment ani operational costs.

E/ECh/CMU/42Page 63

6. PROGRAMME OF ACTION

This chapter g l oha l Ly dc s c r i hc s mccts u r o s to be tnk c n in order to improvethe service: qua l i t.y of t c Lccommuni c a t i.ons and r,;gn.111ing. Since it isimpossible to prepare a programme which i.s va l oablc for all railway companiesat the same time, the Tange of proposed Acti.ons ~s nrccrntcd below in the formof mcdu l c s , so t n.rt the measures C.1n be defined i nd ivi dua l lv ,

~corganiz3tion of the 3d~inistr3tiuns

telecommunication, signalling and energydirectly under from the general manager"

In ord(;r tu concentrate the0.upply ~crviccs in one division

(ii) Creation of salary scales (privatisation of c ornpa n i c s ,r_cmuncr3tion to qualified staff in order to i nc rcc scand avoid their drifting to private c ompanic s ,

... ) for adequatethci r .mot i va t i on

(ii i ) Establishment of plane; w i t b a v i co t o impl-uvi r 1(!,

priority import~ncc to preventive maintenance.include of stockagc of spare p.1rts 2nd tuols.

TT:-<lntcn.1flCC by ai v i ngThese actions must

iv) Upgrading ()f laboratoriescomponents and SP3~C parts.of qualified staff.

hy p r ov i d i ngThere is also

the ncc c s s a r-v instrumentsa :lc\;d to i nc r c as c the numbc r

v) Verification of lightning protections .:1UO posTiblc xc tiub i.Li t a t i on ofthese installations.

vi) Eva l ua t i ons of cxif:.ting equipmentspare parts in the storc and withintervcntions).

{qua lit y of SCTVj.CC, a vn i l ab il i t y ofthe maD1J{3=turcT , 35 well as needs for

vii) Preparation of master plans to define st;:-;·~t·:_'Gics

regard to the evolution of the t c l r-comrnuo ac ct i onsthe most urgent opc~3t'lon and s3fcty needs).

Clnd ba s i c needs withnc t o-or-k so 3S to mr-c t

viii) Idcntific3ticn ofincrease the s3fcty

supplementary t c.Lr.commuo i c a t i.on needs 1n order to

ix) Definition of rehabilitatiunsignalling on the Li nc s i.dc ,block, single-way b Loc k ,signalling, ... ).

s t r a t cg i.c s 31",d t.a s i c needs in the field ofa t s t a tions and level crossings (telephonec lc r r i c or c l cc t r on i c token, automatic

x) Idcnt i f i c a t i on of supplementary needs In

increasing traffic safety (ou r oma t i cdetection, axle-counter, .•. ).

sign311ing systemstrain control,

'vi th ·.riew toend-of-train

xi) Definition of a strategy for succcssi.vcly introducing solar energy intotelecommunications 3S well as sign:lliing.

E/ECA/CMU/42Page 6"7. CONCLUSIONS AND RECOMMANDATIONS

7.1 Conclusions

(i) The latest technology i.n the field of t c lc c ornmuni c a t i ons andmay not a Ivay s be the best solution for the cpc r.a t i on ofnetwork. The more soph i s t i ca t c-d the equipment: the more theon the manufacturer for repair of dcfccti1iO circuits.

s i ana l l i nga railway

dependaney

A inadcqt13cy 1n

operation rCRultsthe maintenance sC'ctor is the

obtained from certain cquipmc:nt.ma1n cause of bad

(iii) Lack of funds is one of the crucial p r ob l c-ns leading to inadequatema i o t cnancc , \'\lhilc c rc a t i ng a new p r oj c-c t , t uc rcvc lnnt a nuua l costs ofmaintenance aloe not always taken i n t o ac co.v.it.

{Lv ) Good c~oicc of a signalling system largct, (lCPCnaS on the forecast ofthe railway t r a f f i c , An ovrrr s i z cd Slf,->1.1.1·(1~-~!:>: equipment wi Ll imo I y

operating i nc rc ascd , If the t ra f f i c IS .:..1 t , an c l cmcn t a r y signallingsystem may Stlfficc~

(v) The hUffinG f:1ctor must not he neglected l

introduced. A s o l i d cra i n i ng is the ll.:lc3:c

charge of rclcvnnt upcr3tions.

if <l nCI< technologyf o r ruot i.va t i on of (he

must bestaff in

(vi) Cc r t a i n signa 1.1ing system'> (single-tt"i1.c..k '·1 oct- r:.utomutic i nt c r l ocking )cannot exclude the possibility of Iur.no-: c r r o r s , For safety r c.t s oris ,there is the need to app l y add i t ioncl methods (ground-t,,:,ain rad i o ,au t oma t i c train control, end-of-train detection) nx Lc r c ount c r, .. ).Taking the r3ilway occident dcscrihed t~e 6 September 1990 in the Frenchnewspaper "Lc Hondc" as an cxamp l c (sec Fi~;Hrc 701), it may he concludedt ha t it could he avoided through r hc 'lFC of one of the above mentionedtechniques.

(vii) Tcc hn i c a l i nadc qunc i c s in lightning protectors arc causing c on s id c r ab Lcdamages to modc r n cnm pmcnt , c s pcc ia l Lv the c l cc c r on i.c onc s ,

("iii)Good track-circuits 16 a prc~unditioll tCll t~iC correct wor1ting of mnnysignalling systems.

(ix) The opc r a t.i.on of diesel s;encT".3tors in gcoa . ic o l Lv .is o l a t cdC3US'C some economic (cost of fuel) a nr! J'_'TI_:..J1.cal (supply)Ilowcvc r the t cchn i oue it s c 1. f is gene...-.:; 1,1. y .o dc con t r oI "

~l. r c a s mayprohlems.

(x ) Solar energy L, already used In novc r-a I .ic two r k s , -uos t l.y fortelecommunications 0 Experience 1-1,"3.5 Shown th:1t the cou i pmcn t .: s quitereliable. The operating cost 1 s ~~cry f avourab lc in c omp a r i s on wit~,

diesel gcnc r ato r s ~ There is not muc '- oxpc r i cncc the usc of pho t ovo l t a i,cpower supply for s1gnal.ling sy~tems.

~\..§~!lt Mal'Cf'lIiIU I;;ere)

Un mort et quatre-vtngt-un blessesdans unecollision. ferroviaire

•

•Jeudi 6 septembre 1990

L; service krro\ dcvuit elf';

'b;thll sur la Hgnc veic uniqueentre Vaknn.-'Cl Gl('llOrl\' dan" 1:1j{HlrnCt" de mercrcdi 5 septerubre11 uvair ('tt'; mterrompu, l:t vcdtc.vets ! 7 ucnres, aprcs unc collinoucetrc.lv Ldgo Harcelonc-Gcnevc I."ftc tr.nn l..<,ull,S:\lJlf-GffV,u;·!\rb"seiile-Nice. survenuc a Saint-Marc<:-Hin,(ht.:fC},Diat' cct accident, 1-('conductcur <111 traru ('(,CHI, .1,1\.>quos Leurat, qnarante ci un ans. nrruuvc Ia.mort taaois que quatrc\11lj!:t'Ufi Pi:l~,j;lgtr'i<. <';f)Uffr;lrH,\\!t.

t{!u! ,klont1J~!UIF, l',.\iem !lk<iv;'il¢M.brHlcnt.

enquctcs j udrciaire ct 'adrnihHO'ativi.." WJl \'.'PJi,t ouvcrtcscsxarvront t!lt determiner pourquoik cowducteur xle Irain Coral! -Jengage son U)!1V\\: sur la V011' utuqu~' on survcnait !l: Tatge. ator,QU'lm Icu tntrl'!,,~!lu <':1\ llJ{cn1rsrtitFaeces. f.n t::l'fc\ ~ci\ln Its pITmieres ";\l1t,\;);:Hi()~,~, d. ....'mble que{a~;gn:di$:;Hien, iii. fmL li(\l1l14~ notm,i!emn<!, (,';~<.::,,;,,-~'m:en:, hnwthese Cit <;1\';11,,:'''.' f<W \:~p!lqun lc

comonrtcrnont aberrant du ntccani':loJl'l, L" {'her degare dc SaintM~m'r:1Hn lui uurait faille signnld'avanccr son train dontI'arrrcrc~cnH;t k fonctionnement d'un passngc a nlvc-au,HalinUti!ltcrpn~tf

cct ordrccnmme une autorisatiorde depart; Qvbliantdc a'asauretque k feu etait au vert.

j.e svstcme dt~sec4ntc 'sur (elkIigne ll'ci[ .pas le pins $ophlst!qu~qui e cistc P-UJslIU'il 'ninterdit pas

l'crrcur: humaine. Le <l C(ilHrl.)!e dt'vitessc », qui empeche Hue rnaeccuvrc nl contradiction .avcc '1('>;

sJ!',naux.,.n'('$t systcmatiqueincnt111staHc'quc5ur, fc~, TOV, .dcpuisIes cmasfroph('$ farrov iaitt'i -ues~tcs 1985 et 1985,il a etc dcddc,tel' ('ti.,~!hIH;aU .rcscac c Itl~~iq~j c.m.us U",\IJl rythmemlenlj p,jric<,O:uiltl1iritesbudgetahcs¢t en ron;,me>i~;:il'n par 1I:,'-s voiesl¢s plus t rcqucntces elks plus cxnosces. L]\<i!":Vakl1cc,,Grcnoblc u'cntruitp<n:. dans (~~'{ categories.

Al. F,

1 ;-,_. '. r r--s s cut: t i.nq

E!ECA!CMU!42Page 66

7.2 Recommendations

(i) The improvement of the maintenance methods 15 " pr cc ond i t i cn for t aki ngmore advant agc of modern t c l ccommun i c a t ion and signalling systems. It isadvisable draw up to maintenance plans.

(ii) External f i n anc i ng of any p ro j cc t shouldparts to operate equipment for at l co s t

regular sl1pply to maintain the level of the

includethl"cC

stored

the s upp l y of spareyears ~ as wc L'l as a

l-J3.rts.

(iii) Whenever modern technology is introduced, the human factor should begiven more a t t cn t i on . Technicians need a good t ra i n i ng and have to beequipped with tools and reliahle transport facilities. They also need asolid motivation so that they "accept II .thc modern techniques Hhic1i mavrequire the change of habits.

:

(iv) The latest technology is notcnvi t-onmcn t . Howovc r , the choiceavailGblc on the market.

necessarily theis determined by

bo s t. for thethe c qu i ;.\fficnt

Africa.nwhich i s

(v ) In order to achieve marc autonomv f r-o-a the manuf a c t u rc r . lesssophistic3ted technigues have to he Bel.ccted, so that l3tC~ on therepair can be done locally. 'I'ak i ng as 3D. cxcmr l c the systems where theoperation depends un the careful maintenance of track-circuits, it isunder certain c i r cums t anc cs pos s i b i.Lc to choosc an c qu i.pmcr t t nn t needsonly few t r acks i.dc i ns t a l l a t i ons ,

(vi) Maintenance workshops and laborDtorics shou l d !'-E::- equipped in sud": a wayt as to reduce the r cp l cc amcnt f rcqucnc y of the cqu i pmc nt and the needsfor foreign exchange.

(vii) The usc of solen energy s hou Ld he l,CC:r:-C:1SC

v i cw to reducing the fuel costs for d i.c s c lsignalling, may rcqui,c 3 pilot project.

extent, especially with agenerators. Its usc for

and cncrp,y are crucial to the safety ofthe c f fic i.cn t ope rat ion of r a i lway services.in the org.1nisation companies where theseto the general directors.

(viii)Telecommunication, s i gna l l i ngpassengers and goods 38 well .1F>

This fact should be reflectedservices stl()uld be directly under

E/ECA/CMU/42Page 67

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•

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de

•

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BraunSChweigMK" I Nanu Lac t u r c r information, Siemens •

20. ilRETB, Radioinformation, GEe

Electronic Token B]()ck Sign311ing") Manufacturer- General Signal Limited} 1988~ Hcrtfordshirc

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Africa (ECA), 19i19, Addis Abab aEconor-Lc Commission for

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telecommunications and signalling . on african railways

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