毕业设计外文翻译.docx

毕业设计外文翻译.docx

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毕业设计外文翻译

ATrainControlSystemforSecondaryLinesbyRadioBasedTrainDetection—COMBAT

Abstract

Therehasbeenagrowingdemandforalow-cost,low-maintenancesignalingsystemoncash-strappedsecondarylines.Tomeetthisdemand,wehavedevelopedthenewComputerandMicrowaveBalise-AidedTrainControlSystem（COMBAT）.SpecificfeaturesofCOMBATaretheapplicationofmicrowaveradiobalisesfortraindetectionandcentralizedinterlockingandblockfunctions.Thispaperintroducesthesystemconfiguration,itsbasicfunctions,anditsbenefits.

Keywords:

COMBAT,Traincontrolsystem,Traindetection,Microwavebalise

1.Introduction

Over15yearshavepassedsinceelectronicblockingsystemsintroducedintolineswithlowtrafficdensities.Asmostarecash-strapped,theselinesarefacingdifficultiesininvestingthelargesumrequiredtoupdatethesesystems,somehavingeithershelvedmodernizationplanorevenbeencompelledtoretainold-fashionednon-automaticversions.Inordertoaddressthisproblemandprovideenhancementstosafetyandefficiency,thedevelopmentofanewlow-costtrainsystemneedstobeaddressedwiththeutmosturgency.

Inaddition,trackcircuitsarealsowidelyusedfortraindetectionandfaultsoftraindetectionresultingfromrustordirtonthesurfaceoftherailshavebecomeaseriousproblemonlowtrafficdensitylines.Sincetrackandweatherconditionsaffectthismethodoftraindetection,itisnecessarytoadjustandmaintaintrackcircuitsperiodicallywithresultantincreasesinmaintenancecosts.

Tosolvetheseproblems,wehavedevelopedthenew,low-costComputerandMicrowaveBalise-AidedTrainControlSystem（COMBAT）foruseonsecondarylines.ThemainfeatureofCOMBATistouseanewtraindetectionmethodthatbasedonradiocommunicationsinsteadofconventionaltrackcircuits.Moreover,withregardtoitsinterlockingandblockfunctions,COMBATcontrolstrainsalongtheentirelinelengthbymeansofacentralizedinterlockingsystem.TheintroductionofCOMBATprovidesarangeofbenefitssuchassafetyenhancements，improvementstotrafficcontrolefficiency,andthereductionsinequipmentandmaintenancecosts.

ThispaperintroducestheCOMBATsystemconfiguration,itsbasicfunctionsandrangeofbenefits,andpresentstheresultsofmonitoredfieldevaluationtests.

2.Developmentconcept

WeaimedatintroducingCOMBATonlowtrafficdensitylinesanddevelopeditaccordingtothefollowingconcepts.

Todetecttrainswithoutusingtrackcircuits,weaimedatachievingasolutiontothetraindetectionproblemsonlowtrafficdensitylinesandtraindetectionwithoutusingtrackcircuitsorcontactingtrains.Doingsowouldenhancesafetyduringinstallationandmaintenanceworkandreducetherelatedcosts.

Tocentralizeinterlockingandblockfunctionsonsecondarylinesthatareonlyprotectedbynon-automaticequipmentsuchasthetabletinstrumentblocksystem,itisnecessarytoposttrafficoperationsstaffateachstation.Tomaketrafficcontrolmoreefficientandreducemaintenancecosts,weadoptedacentralizedinterlockingsystemthatperformsinterlockingandblockfunctionsatatrafficcontrolcenter.

Toutilizeexistingsignalingequipmenteffectivelysincemostsecondarylinesareexperiencingfinancialdifficultiesintermsofinvestment,itisnecessarytominimizetherenewalcostsofanewtraincontrolsystem.Tothisend,weaimedatachievingatraincontrolsystemthatasfaraspossiblemakeseffectiveuseofexistingsignalingequipment.

3.Systemconfiguration

COMBATisatraincontrolsystemachievedbyusingacentralizedinterlockingsystemofthedispersedfunctiontype.Acentralinterlockingunitperformsinterlockingandblockfunctionsforthewholeline.Eachstationonthelineisequippedwithaninterlockingunitthatcontrolsfieldequipmentsuchassignalsandswitches.Telecommunicationlines,throughwhichindicationdatapasses,connectthecenterwitheachstation.

Fortraindetection,COMBATusesasystemcomposedofmicrowavebalises（interrogators,waysiderespondersandon-boardresponders）andatraindetectionunit,andperformstraindetectionbyradiocommunications.Setsofinterrogatorsandwaysiderespondersinstalledatthehomeandstartsignalpositionsconstituteatraindetectionpoint.Twoon-boardrespondersareinstalledatthefrontandrearofeachtrain,eachrespondercontainingdatatoidentifythetrainIDandtheexactlocationoftheresponder.Whenatrainpassesatraindetectionpoint,theinterrogatorreceivesdatafromtheon-boardrespondersandrelaysittoeachstation'straindetectionunit.

4.Basicfunctions

Traindetectionfunctionsdispensingwiththeneedtohavecontactwiththetrainitself,COMBATdetectsatrainbyusingpointdetectionprinciplesatpositionswheremicrowavebaliseshavebeeninstalledalongsidethetrack.ToensurethattheCOMBATsystem'sabilitytodetecttrainsisassafeasorsaferthanthatusingtrackcircuits,aclosedloopestablishedbycontinuousmicrowaveradiocommunicationshasbeenadopted.

Theclosedloopisinconstantusebetweentheinterrogatorsandthewaysideresponders.Atrainshutsofftheclosedloopwhenitpassesthedetectionpoint,andCOMBATdetectsitspresence.EveniftheCOMBATequipmentbreaksdown,safetyisensuredastheclosedloopisalsoshutofftoconstituteacasewhereatrainispresent.

Theareabetweentwoadjacentdetectionpointsistermedadetectionsectionthatcorrespondstoaconventionaltrackcircuit.Asatrainprogressesalongthetrack,theinterrogatorreceivesdatafromtheon-boardrespondersandthesystemcansimultaneouslyidentifythetrainfromthereceivedtraindataanddetectthetrain'sdirectionoftravelfromthesequenceinwhichon-boardresponderdataisreceived.

COMBATmanageseachdetectionsectionaccordingtothereceiveddatafromeachinterrogator.Atrain'sentryintoandexitfromeachsectionaredetectedaccordingtowhetherithasestablishedorshutofftheclosedloop,thereceiptofthetrain'sID,andtheon-boardresponderdatasequence.Howthetraindetectionsectionsfunctionasatrainpassesisshowninthese.

（1）Inthefirstphase,whentheclosedloopisestablishedatbothdetectionpoints,thestatusofthedetectionsectionistermed"non-presence."

（2Whenatrainentersthesection,oneclosedloopisshutoffandthestatusofthesectionischangedtounconfirmedpresence."

（3）Whentheinterrogatorreceivesdatafromtwoon-boardrespondersinthecorrectsequence,thesystemdetectsthetrain'sIDanddirectionoftravel.Thesectionstatusthenbecomes"confirmedpresence"andthetrainIDisrecorded.

（4）Whileatrainistravelingbetweenthedetectionpoints,thestatusofthesectionismaintainedas"confirmedpresence."

（5）Whenatrainpassesbytheotherdetectionpointandtheinterrogatorreceivesdatafromthetwoon-boardrespondersinstalledattherear,thesystemdetectsthattheprogressingdirectionofthetrainis"exiting."However,thestatusofthesectionandrecordedtrainIDaremaintained.

（6）Whentheclosedloopisreestablished,the"exiting"ofthetrainhasbeendetectedcorrectly.Asaresult,thestatusofthesectionrevertsto"non-presence"andthetrainIDiscanceled.

OncethetrainIDisrecordedinthedetectionsection,itisnevercanceledunlesstheexitingofthesametrainIDisdetectedcorrectly.EveniftwoormoreIDsarerecorded,onlytheIDofatrainthatisdetectedashavingexitedcorrectlywillbecanceled.Moreover,sinceCOMBATdetectstrainIDsandconstantlymonitorsthepresenceoftrains,itcanfulfilltraintrackingasabasicfunction.Therefore,thesafetyandreliabilityoftraindetectionareenhanced.

Interlockingandblockfunctions:

COMBAT'sinterlockingandblockfunctionsareachievedbyacentralizedinterlockingsystemthathasacentralinterlockingunit（CIU）atitsheartandastationInterlockingterminal（SIT）ateachstation.

TheCIUperformsinterlockingbetweensignalsorbetweensignalsandswitchesalongtheentirelengthoftheline.SincetheinterlockingfunctionofthewholelineiscentralizedbytheCIU,COMBATcanprovidetotalinterlockingcoverageasifitwereonestationandtheblockfunctionbetweenstationscanbeachievedbyinterlockingallstartsignalsbetweenadjacentstations.Moreover,usingasystemoftrainIDsforinterlockingbetweenstationsenhancesthesafetyoftheblockfunction.

TheSITcontrolssignalsorswitchesaccordingtocontroldatareceivedfromtheCIU.Toreducedatacommunicationloadsbetweenthecenterandeachstation,theSIThasseparatefunctionsto（a）locktheswitchafterthecompletionofanoperationand（b）tochangetherelevantsignalstostopaftertheentryofatrainontoasectionoftheline.

AnoutlineoftheinterlockingandblockfunctionsofCOMBATisshowninthese.

（1）WhentheCIUreceivesaroutesettingrequest,itchecksconflictingroutes.Iftherequestedroutecanbeset,ittransmitsswitchcontroldatatotheSIT.

（2）TheSIToperatesandlockstheswitchesontherouteaccordingtothecontroldatareceivedfromtheCIU,andtransmitsthedataconfirmingthecompletionofswitchcontrolbacktotheCIU.

（3）TheCIUreceivestheswitchlockingindicationdatafromtheSIT,andtransmitsthesignalcontroldatatotheSIT,whichgivesthesignaltoprecedeaccordingtotheCIUcontroldataandtransmitsthestartsignaldatabacktotheCIU.

（4）Whenatraindepartsandshutsofftheclosedloopatthestartsignal,theSITchangesthestartsignaltostop.TheCIUthenlockstheblockbetweentherelevantstationswiththetrainIDtransmittedfromthetraindetectionunit.

Whenatrainarrivesatthehomesignalof