A SIMULATION MODEL FOR LIGHT RAIL TRANSPORTATION SYSTEM

A SIMULATION MODEL FOR LIGHT RAIL TRANSPORTATION SYSTEM Filiz Dumbk (a), Dilay Clbi (b) (a)(b) Dpartmnt of Managmnt Enginring, Istanbul Tchnical Univrsity, Macka 7, Istanbul, Turky (a) dumbk@itu.du.tr, (b) clbid@itu.du.tr ABSTRACT Public transportation has a stratgic importanc spcially in larg citis with rspct to incrasing population. Subway and light rail systms ar fficint passngr transportation systms in larg citis du to thir larg capacitis and thy ar usually fastr than othr transportation tools. Incrasing dmand for ths transportation systms has brought up th us of complx modls to incras fficincy of th systm by rducing tim dlays and passngr waiting tims. In this study, a simulation modl has bn dvlopd to dtrmin bst opration stratgy in Istanbul Light Rail Transportation Systm (LRTS). Currntly, Istanbul LRTS ntwork has 8 stations and a total lngth of 9, km. This ntwork provids transportation srvic for. passngrs vry day and oprats according to prdfind timtabls which diffr du to th oprating sason and day of th wk. Th systm was dvlopd as a discrt vnt simulation modl and Arna Simulation Softwar was usd. Kywords: simulation, light rail transportation, passngr srvic quality. INTRODUCTION Efficint managmnt of rail systms that prsnts an ffctiv solution for th big citis which ar gtting crowdd day by day is vry important in trms of oprational fficincy and passngr srvic quality. Public rail transportation planning procss has bn dividd into stratgic, tactical and oprational lvls (Ghosiri, Szidarovszky, and Asgharpour ). Dmand analysis and lin planning ar considrd in th stratgic planning lvl. Rolling stock planning, crw schduling, crw rostring ar considrd in th tactical planning lvl. Train schduling that includs dpartur tims of th trains for spcifid routings tak plac btwn tactical and stratgic planning lvls. Thrfor, schduling procss of th trains has significant importanc to provid oprational fficincy and passngr srvic quality. Hooghimstra and Tuniss (998) indicat that travl tims and halting tims, plus possibly a maximum travl tim btwn th nd stations, constrain th timtabl of an individual train. Whil timtabls ar bing constructd, srvic quality of th systm should b takn into considration. Vanstnwgn and Oudhusdn (7) indicat that passngr waiting tim is a critical factor to valuat passngr srvic quality. Yalcinkaya and Bayhan (8) dvlopd a modl optimiz avrag travl tim for a mtro lin by using simulation and rspons surfac mthodology. Hadways which rprsnt tim intrval btwn two conscutiv trains wr calculatd to find optimum rat of carriag fullnss and avrag travl tim (Yalcinkaya and Bayhan 8). In this study, a simulation modl was dvlopd to dtrmin optimum procss stratgy in Istanbul Light Rail Transporation Systm (LRTS). This ntwork was foundd in 989 and bn xpandd ovr yars. Currntly, Istanbul LRTS ntwork has 8 stations and total lngth of 9, km. This systm has diffrnt tim tabls on wkdays, Saturdays, and Sundays.. SYSTEM STRUCTURE Istanbul LRTS was foundd in 989 and currntly has 8 stations. Istanbul Ulasim Corporation has 9 wagons and 8 of ths wagons ar bing usd. 7 vhicls oprat in ntwork and ntwork has. passngr transport capacity pr day. Figur shows th rail ntwork of Istanbul city. Rd colord ntwork indicats Istanbul light rail transportation systm. Figur : Istanbul Rail Ntwork In dvlopd modl svn stations (Aksaray, Emniyt, Ulubatli, Bayrampasa, Sagmalcilar, Procdings of th Intrnational Confrnc on Modling and Applid Simulation, MAS 9 ISBN 978-8-9-7-

Kartaltp, Otogar) of this ntwork wr takn into considration. Systm oprats btwn : am and : am. Simulation modl was dvlopd to rflct systm structur according to ths prdfind constraints.. Numbr of vhicls. Minimum signalization tim btwn train arrivals for on dirction. Wagon capacity. Minimum train dwll tims at stations. Minimum transfr tim btwn two stations. Vhicl vlocity Currntly 7 trains oprat in LRTS. On of ths trains hav usd for ring srvics btwn two stations and this movmnt of trains wr not includd in modl. Thrfor, trains will oprat btwn spcifid stations. Signalization systm that is usd in th systm allows train arrivals with minimum minuts tim intrvals. On wagon has 7 passngrs carriag capacity. A vhicl oprats with four wagons and total passngr carriag capacity is 8. Trains stop in stations for passngr alighting and boarding activitis at th stations. Dwll tims of th trains chang according to th station, prdfind tim intrvals during a day and train trip dirctions. Minimum transfr tims dpnd on train vlocity and th distanc btwn stations. Train vlocitis can chang btwn stations but avrag vlocitis wr usd. Vlocitis of th trains did not chang during th modl. Thrfor transfr tims btwn stations hav bn dfind constant according to th currnt data takn from Istanbul Ulasim Corporation.. METHOD Rail ntwork is a dynamic systm that changs during tim and variabls in this systm chang at discrt tims. Thrfor, modl was dvlopd as discrt simulation modl. By taking systm structur into considration rlatd data was collctd as indicatd in sction.. Arna simulation softwar packag was usd to dvlopd modl and this modl basd on basic assumptions which ar indicatd in sction.. Sction.. xplains th usd Arna componnts and sction.. xplains th modl vnts which ar occuring in th systm... Data Collction Passngr arrival pattrns wr dfind according to th collctd data at stations within minuts intrvals btwn January 8 and Novmbr 8. Approximatly half million rcords wr loadd to Oracl databas. Rcords that rprsnt wkday arrivals to th stations wr takn into considration and avrag numbr of th passngr arrivals within minuts was obtaind. Istanbul Ulasim Corporation conductd a survy to obtain prcntags of alighting passngr at th stations. Tabl shows th obtaind rsults from this survy. For xampl, it was shown that %,9 of passngrs who starts thir trip from Aksaray station alight at Emniyt station. This information was usd to updat th numbr of th passngrs in th train and train s currnt capacity was calculatd aftr this updat. Tabl : Prcntags of Alighting Passngrs at th Stations Trip Ending Station Aksaray Emniyt Ulubatli Bayrampasa Sagmalcilar Kartaltp Otogar Trip Starting Station Esnlr Aksaray.... 7. 8.8.7 9.. 9.7..8.. Emniyt.9.. 8... 7.7 9. 7....8.. Ulubatli.7.7.9.9.8...8.9.8 Bayrampasa.7. 7..8 9. 8..9 9.. 9. Sagmalcilar.8. 9...9.8...8 8.7 8.. Kartaltp 9.7. 9.7..8.8. 9.7.8..8 Otogar......8 9. 7. 9.. 8.7.8. 9. Esnlr...7 9.7...9 7.. 9. 7... Trazidr.9..7.8...8.8. Davutpasa.9. 8.. 7.... Mrtr 9...7 8.8.9. Zytinburnu.8 9...7 8... 8..8..8 7..8.. Bakırkoy.9.. 8. 8...8.8.7.. Bahclivlr... 8..9.9. 7. 7.... Atakoy 7.8..7.7.8.8 9.. 9.7.. 9. Ynibosna 9.7 8. 8..9 8...8..7.8..9 9.9..9 DTM.. 7.. Havalimani.9...7.7.9.. 8. Currnt data rprsnts numbr of passngrs that ntrs to th stations within spcifid tim priods. Dstination of any passngr ntring th systm was assignd basd on th probabilitis dtrmind through this conductd survy... Modl Assumptions Simulation modl was dvlopd basd on th following basic assumptions: Trazidr. Trains oprat on a singl unidirctional track.. Th systm is a trminating systm and works for prdtrmind hours of a day.. Spds of th trains ar systm variabls, but thy do not chang during a trip.. Intr-arrival tims of passngrs ar xponntially distributd with rats givn in minuts intrvals.. Dwll tims at stations ar function of arrival tim of th passngrs waiting in th station and gtting off th train.. Only on train is allowd at a tim in a station. 7. Passngrs wait for trains in stations and gt on th train according to th train s currnt capacity and numbr of passngrs on it. 8. If thr is no train to board at dpartur tim du to a dlay, passngrs go on waiting for a train until train arrivs. Thr will b no adjustmnt in timtabl du to this dlay. 9. Trains can follow diffrnt routs dpnding on th schdul. Half routs ar allowd.. Th systm rprsnts normal conditions. Failurs in railway or trains ar not includd.. Hadways ar dtrmind bfor th simulation modl is run. Hadways can b diffrnt for diffrnt tim intrvals, but th hadway for a tim intrval is fixd during th running of th simulation modl. Davutpasa Mrtr Zytinburnu Bakirkoy Bahclivlr Atakoy Ynibosna DTM Havalimani Procdings of th Intrnational Confrnc on Modling and Applid Simulation, MAS 9 ISBN 978-8-9-7-

. Simulation modl of th systm was dvlopd for svn stations. Othr part of th systm was takn into considration by calculating trip tims according to th train cycls and adding this tim to th dlay tims in th modl.. All passngrs in th train alight at th trminal stations... Modl Componnts Numbr of stations, distancs btwn stations, numbr of trains and thir vlocitis ar controllabl input variabls of th systm. In dvlopd modl, ths Arna moduls wr usd for modling th systm vnts: Crat, Transportr, Rqust, Fr, Dispos, Station, Assign, Rout, Schdul, Fil, Rad/Writ, Signal, Hold, Dlay, Dcid, Sparat, Rcord. Crat modul was usd to gnrat passngrs at th systm according to th dfind arrival typ schduls according to th collctd and analyzd passngr for ach station and dirction. Also this modul was usd to dirct drivrs to start thir trips. Transportrs wr usd to dfin limitd numbr of trains in th systm. Trains start thir trips by using of rqust modul and at th nd of trips thy wr rlasd with fr modul. Dispos modul was usd to rmov waiting passngrs from th stations aftr th train arrivals. Signal and hold moduls work coordinatly in th modl. A signal valu was snt to th rlatd station aftr train arrivals and waiting passngrs at hold modul s quu was rlasd and disposd. Stations rprsnt th prdfind svn stations at th systm. Systm was dvlopd as a circl ntwork and on station was dfind as two stations in Arna modl that rprsnts diffrnt dirctions of train movmnts at th stations. Tabl rprsnts th dfind stations in th modl. Tabl. Dfind Stations in Dvlopd Modl Station Station Short Nam Station Cod Station Typ Aksaray Start AKS Start St Station Aksaray AKS* St Station Emniyt EMT* St Station Ulubatli ULU* St Station Bayrampasa BAY* St Station Sagmalcilar SAG* St Station Kartaltp KRP* St Station Otogar OGA* St7 Station Otogar Start OGA Start StA Station Otogar OGA** StA7 Station Kartaltp KRP** StA Station Sagmalcilar SAG** StA Station Bayrampasa BAY** StA Station Ulubatli ULU** StA Station Emniyt EMT** StA Station Aksaray AKS** StA Station * Ths stations ar usd for th trips at Otogar dirction. * Ths stations ar usd for th trips at Aksaray dirction. Assign modul was usd to mak assignmnts or changs in systm variabls and attributs according to th dfind quations. Rout modul was usd to transfr trains btwn stations at spcifid tims. Train schduls wr dtrmind outsid of th systm and train trip start tims and dirctions wr rad from a prdfind fil. Sparat modul gnrats a nw ntity to rad nxt dpartur whil th ntitis wr starting thir trips. Train dwll tims at stations wr kpt at dlay modul. Dcid modul was usd to control signalization tim factor and only trips that hav minimum minuts was allowd to start trips as shown in th first xprssion othrwis thy waitd until th minimum tim intrval was providd as shown in th scond quation. Trminal Station Dpartur Tim >= Prvious Dpartur Tim + () Dlay Tim = (Trminal Station Dpartur Tim Prvious Dpartur Tim) () Rcord modul kps th tim btwn arrival statistics of passngrs at ach station and tim btwn arrival statistics of trains for trminal stations. Furthrmor ths attributs and variabls wr dfind in th dvlopd modl:... Attributs Attributs ar usd to attach spcific valus to th ntitis that can diffr from on ntity to anothr. In dvlopd modl ths attributs wr dfind: Train capacity: 8 was assignd in th bginning of trips. Numbr of passngr in th train: was assignd in th bginning of trips and this valu was updatd at stations according to th numbr of passngrs that got on th train at this station. Numbr of alighting passngrs in spcifid stations: Numbr of boarding passngrs was multiplid by prcntags of alighting passngrs for th nxt stations and attributs wr assignd. Trip start tim: Spcifid timtabls includ train trip start tims for th trminal stations. This attribut kpt ths start tims and it was usd in dlay modul to dfin rquird waiting tim as diffrnc btwn assignd trip start tim and systm tim. Train rout: Dvlopd modl allows dfining various routs for diffrnt rquirmnts. At trminal stations this attribut was assignd and it was controlld at dfind dcision points.... Variabls Variabls ar usd to rflct th stat of systm for spcific purposs and thy ar not attachd to th ntitis. In dvlopd modl ths usr dfind variabl wr dfind: Numbr of waiting passngrs at stations: This variabl was incrasd with pr passngr arrival and dcrasd aftr train arrivals to th stations. Numbr of Procdings of th Intrnational Confrnc on Modling and Applid Simulation, MAS 9 ISBN 978-8-9-7-

waiting passngrs at stations was updatd aftr boarding of passngrs to th trains as th diffrnc btwn numbr of waiting passngrs and numbr of boarding passngrs. Numbr of boarding passngrs at stations: Trains hav limitd capacity to transfr passngrs btwn stations. Numbr of boarding passngrs at stations dpnds on availabl capacity of trains and th numbr of waiting passngrs at stations. Minimum valu of numbr of waiting passngrs and availabl capacity of trains gav th numbr of boarding passngrs. Plannd dpartur tim from trminal stations: Signalization systm ncssitats controlling minimum tim intrval btwn dparturs. This variabl was dfind for both Aksaray and Otogar stations which ar trminal stations in th systm. Plannd train dpartur tim was kpt in this variabl. Actual dpartur tim from stations: This variabl was usd to kp th actual dpartur tim from stations aftr rquird controls wr don. Trains startd thir trips without any dlays if diffrnc btwn plannd dpartur tim and actual dpartur tim is gratr than or qual minuts. Othrwis, trains dparturs wr dlayd to provid rquird tim intrval... Modl Evnts Simulation modl dvlopmnt was dividd into 8 main vnts and ths vnts wr takn into considration.. Trip startings ar dclard to th drivrs. This vnt occurs according to th pr-dfind timtabls.. Drivrs rqust th narst train basd on th smallst distanc rul. Availabl trains ar matchd with drivrs. If thr ar no any availabl trains, drivrs will wait until trains bcom availabl.. Trains arriv to th stations within spcifid duration. Ths durations wr obtaind from Istanbul Ulasim Corporation basd on prvious data collctions.. Passngrs alight from th train. Numbr of passngrs that alight at th station ar dtrmind by prviously assignd attribut with ths quations. Th scond quation is rpatd until all prvious stations data was vaulatd. ANINT function of Arna was usd to dfin numbr of passngrs as intgr valus. No. of alighting passngrs at Station X = ANINT (No. of boarding passngrs at bginning station * Alighting passngr ratio for station X) () No. of alighting passngrs at Station X = No. of alighting passngrs at Station X + ANINT (No. of boarding passngrs at th scond station in th train dirction* Alighting passngr ratio for Station) (). Trains dlay at stations for alighting and boarding activitis. Dlay tims wr obtaind from Istanbul Ulasim Corporation basd on prvious data collctions for th stations.. Passngrs arriv to th stations and numbr of th waiting passngrs incrass. No. of passngrs at th station at th station = No. of passngrs at th station at th station + () 7. Aftr th train arrivals, passngrs gt on th train and numbr of waiting passngrs in th station dcrass according to th train capacity. Following quation was usd to provid this. MN function of Arna was usd to gt th minimum valu of th availabl passngr capacity in th train and numbr of passngrs at th spcifid stations. No. of alighting passngrs = MN ((Capacity No. of passngr in th train), No. of passngrs at th station at th Station X) () 8. In Aksaray station trains rout may vary du to th passngr dmand and som trips ar kpt shortr. Routings of th trips ar assignd with dpartur tims in th bginning of th trips. Also, according to th last dpartur tim from th trminal stations trains may b frd. Following xprssion was usd to control this in dcid modul: TNOW <= Last dpartur tim (7) TNOW rprsnts th systm tim and incrmnts during simulation run. Until TNOW is gratr than last dpartur tim, trains lav stations; othrwis thy ar frd. Appndix A shows th structur of dvlopd Arna simulation modl.. EXPERIMENTATION Th modl is vrifid by dvloping th modl in a modular mannr, using random dbug points, substituting constants for random variabls, manually chcking th rsults, xtrm cas analysis, and animating th systm. Exprimnts wr dsignd to provid a structurd framwork that xplains simulation xcution logic in trms of modl componnts. Exprimntal dsign provids an stimation how changs in input factors affct th rsults, or rsponss of th xprimnt (Klton ). Scnario analyss hav bn conductd on th dvlopd modl. Dvlopd modl was validatd with dsignd controlld xprimnts. Passngr arrivals, train schduls and numbr of trains that oprats in railways was dfind as paramtrs and xprimnts wr prformd on th dvlopd Arna simulation modl. Modl was xcutd within minuts Procdings of th Intrnational Confrnc on Modling and Applid Simulation, MAS 9 ISBN 978-8-9-7-

G lis i G lis i G lis i G lis i G lis i G lis i G lis i G lis i G lis i G lis i G lis i G lis i B k l m B k l m B k l m B k l m B k l m Bk lm B k l m Bk lm B k l m B k l m B k l m B k l m EM T G lis lr UL U BA Y SAG KR P EM T UL U BAY SAG KRP AKS AK S Bk lm Ku y r uk t a Bklm Bk lm Bklm Ku y r uk t a Bk lm Bklm Bk lm Bk lm Bklm Ku y r uk t a Bklm B k lm K uy r uk t a B k lm K uy r uk t a Bas lan gic AK S EM T UL U BA Y SA G KRP O G A Cik is i I lk T r n B as lang ic AKS EM T UL U BAY SAG KRP O G A Cik is i I lk T r n T albi T r n Ta lbi Tr n G lis i Tr nin G lis i Tr nin Tr nin G lis G lis i Tr nin Tr nin G lis i G lis i Tr nin T r nin G lis i I n d ir m 7 T r nin G lis G lis i T r nin Tr nin G lis i G lis i T r nin T r nin G lis i I n d ir m 7 T r n M ak inis t E s l m T r n M a k in is t Es l m Ro ut Bk lm I n d ir m I n d ir m I n d ir m I n d ir m I n d ir m G idis Yo nun Scim i G or Yol Ro ut E ls Bk lm I ndir m I ndir m I n d ir m I n d ir m I n d ir m G idis Yonun Sc im i G or Yol E ls A KSARA Y a g ondr A KS S f r A r aligi HV L B k lm Bk lm Bklm B k lm g lis T r n G id is Y o n u = = T r n G id is Y o n u = = Tr ni Bir ak S r bs t AKS ARAY a gon dr ES E g lis AK S S f r Ar a lig i Bklm Bklm Bk lm S f r Bit is i Bk lm Bklm glis T r n G id is Y o n u = = T r n G id is Y o n u = = Tr ni Bir ak Sr bs t HVL ESE glis B k lm S f r B it is i Bin d ir m Bindir m B indir m Bindir m Bin d ir m Bin dir m T r n M a k in is t Es l m O G A Bin d ir m Bin dir m Bindir m Bin d ir m Bin dir m T r n M a k in is t Es l m O G A Bin d ir m B lir lm B lir lm Say ilar i Blir lm Sa y ila r i B lir l m Say ilar i Blir lm Blir lm Say ilar i Blir l m Blir l m B lir lm Blir l m G u n c l O G A I s t as y onu m i? m us ait Blir l m B lir lm F a ls Du r ak t ak i G u n c l O G A I s t a s y onu m i? m us ait F a ls T r u T r u S a y is in i G u n c l G u n c l G u n c l Du r ak t ak i G u n c l G unc l 8 Dlay G u n c l S a y is in i G u n c l S a y is in i G u n c l G u n c l G u n c l 8 Dla y EM NI Y ET Du r a k At am as i EM NI YET D u r a k A t am a s i ULUBATLI BAYRAM PASA SAG M ALCI LAR g idis K ARTAL TEPE O TO G AR ARA G ond r I s t as y ona ULUBATLI BAYRAM PASA SAG M ALCI LAR KA RTAL TEPE O TO G AR ARA G ondr I s t as y o na rplication lngth and modl was rplicatd tims. Bas tim unit was dfind as minuts. In currnt systm, trains ar schduld mor frqunt in morning hours. Firstly, currnt systm s avrag passngr waiting tims hav bn found for spsifid stations. Exprimnts hav bn conductd with, and minuts train arrival intrvals. Figur indicats th avrag passngr waiting tims by changing train arrival frquncis. Passngr Waiting Tims (minuts) 9 8 7 AKS EMT ULU BAY SAG KRP OGA Stations KRP SAG BAY ULU EMT Currnt Schdul minuts arrival frquncy minuts arrival frquncy minuts arrival frquncy Figur : Avrag Passngr Waiting Tims for Diffrnt Timtabls It was obsrvd that dcras in hadways cannot provid xpctd dcras in avrag passngr tims without changing numbr of trains in som cass. minuts tim intrval btwn trains arrivals cannot b implmntd with currnt capacity,,89 minuts avrag tim btwn arrivals was masurd in trminal stations. In currnt systm, thr xists 7 trains activ and of ths trains oprat btwn dfind 7 stations in th modl. Currnt schdul has bn usd in xprimnts that numbr of trains hav bn changd as,, and avrag passngr waiting tims wr obsrvd. Passngr Waiting Tims (minuts)... 8..... AKS EMT ULU BAY SAG KRP OGA KRP Stations SAG BAY ULU EMT Currnt Systm w ith trains trains trains trains Figur : Avrag Passngr Waiting Tims for Diffrnt Numbr of Trains in trains and dwll tims of th trains in spcifid stations wr analyzd and xprimnts wr mad. Passngr waiting tims wr obtaind in th basis of xisting systm. Changs in th systm s prformancs masurs for diffrnt conditions wr obtaind by changing train frquncis and th numbr of trains in systm. In conclusion, incras in th train arrival frquncis during tim priods whn passngr arrival rat is high causs dcras in avrag passngr waiting tims. It has bn obsrvd that th numbr of trains is an important factor to implmnt spcifid schduls and spcifid schduls cannot b applid in cass whn th numbr of trains dcrass. Th simulation modl built in this study is a gnric modl that can b asily changd to adapt th changs in th numbr of trains and train schduls. By running th modl, svral what-if qustions of oprations managmnt can b rplid to mak rvisions. It might also provid suggstions on stratgic infrastructur dvlopmnt, and thus provid a starting point for th construction of any nw infrastructur, namly capacity planning. It has bn obsrvd that th numbr of trains is an important factor to implmnt spcifid schduls and spcifid schduls cannot b applid in cass whn th numbr of trains dcrass. This study rprsnts an fficint tool to masur passngr dwll tims in stations by changing th train schduls and fasibility of pr-spcifid train schduls with by masuring its ffct on rail transportation.. FUTURE RESEARCH Th scop of th scond stag of th rsarch is to xpand th modl by adding othr stations of th ntwork and provid intgrity to valuat th systm prformanc. Also, transfr tims btwn stations will b dfind as usr dfind variabl and othr possibl timtabls ffcts on th systm will b masurd. APPENDIX APPENDIX A. Dvlopd Arna Modl Incras in th numbr of trains whil currnt timtabls wr bing implmntd did not affct avrag passngr waiting tims. Dcras in th numbr of trains causd dlays in prdfind timtabl and currnt tabl could not b implmntd with and trains. Avrag passngr waiting tims hav incrasd du to incras in hadways.. RESULTS AND CONCLUSION Dvlopd modl was implmntd for Aksaray- Havalimani light rail mtro systm for svn stations. In this study, th numbr of passngrs that ar transportd Procdings of th Intrnational Confrnc on Modling and Applid Simulation, MAS 9 ISBN 978-8-9-7- 7

REFERENCES Ghosiri, K., Szidarovszky, F., Asgharpour, M.J.,, A multi-objctiv train schduling modl and solution. Transportation rsarch, 8 (), 97-9. Hoohimstra, J.S., Tuniss, M.J.G., 998. Th us of simulation in th planning of th Dutch railway srvics. Procdings of th Wintr Simulation Confrnc, pp. 9-. Dcmbr -8, Washington (Washington, USA). Klton, W.D.,. Exprimntal dsign for simulation. Procdings of th Wintr Simulation Confrnc, pp. -7. Dcmbr -, Orlando (Florida, USA). Vanstnwgn, P., Oudhusdn, D.V., 7. Dcrasing th passngr waiting tim for an intrcity rail ntwork. Transportation rsarch, (), 78-9. Yalcinkaya, O., Bayhan, G. M., 8, Modling and optimization of avrag travl tim for a mtro lin by simulation and rspons surfac mthodology, Europan journal of oprational rsarch, 9 (), -. AUTHORS BIOGRAPHY FILIZ DUMBEK graduatd from Managmnt Enginring dpartmnt of Istanbul Tchnical Univrsity in 9. DILAY CELEBI is acadmician of Managmnt Enginring dpartmnt at th Istanbul Tchnical Univrsity. Sh rcivd hr Ph.D. from Istanbul Tchnical Univrsity in 8. Procdings of th Intrnational Confrnc on Modling and Applid Simulation, MAS 9 ISBN 978-8-9-7- 8