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ChinaHigh-SpeedRailwayAstheeconomicgrow,intercitytraveldemandhasincreaseddramaticallyintheGreaterChinaArea.Traditionalrailwayscanhardlysatisfythepassengerandfreighttraveldemand,highspeedrailishenceproposedandconstructedafter1990s.Thisstudyaimstointegratecurrentdevelopmentofbothrail-basedandMaglevhighspeedtrainsinthisarea.From1997,Taiwankicked-offitshighspeedrailconstructionbyimportingthetechnologyofJapaneseShinkansen.TheTaiwanHighSpeedRailisa15-billionUSdollarsproject.Tosavethecostofconstructionandmanagement,theBOTmodelwasapplied.Thoughnottotallysatisfied,thisprojectisstillsuccessfulandreadytooperateinthe4thquarterof2007.Chinaispreparingitshighspeedrailservicesbyupgradingcurrentnetworks.Thecapacityandoperatingspeedareallincreasedafter5-timessystemupgrade.The6thupgradewillbeinitiatedin2006.Bythen,trainswillrunataspeedof200km/hinatotaldistanceof1,400kmin7differentroutes.FromthewhitepaperpublishedbytheMinistryofRailwayinChina,therewillbetotally8rail-basedHighSpeedTrainservices.FourofthemareNorth-Southbound,andfourofthemareEast-Westbound.5ofthe8HighSpeedRailsarenowunderconstruction,thefirstlinewillbefinishedin2009,andthe2ndonewillbein2010.By2020,therewillbetotally12,000kilometershighspeedrailservicesinChina.The250billionUSdollarsconstructioncoststillleavessomeuncertaintiesforalltheseprojects.Finally,thefutureoftheMaglevsysteminChinaisnotsobrightasrail-based.Shanghaiairportlinecouldbethefirst,alsothelastMaglevprojectinChinaiftheapprovedShanghai-Hangzhoulinecannotraiseenough4.4billiondollarstobuildit.SteelrailcompositionSteelrailiscomposedofiron,carbon,manganese,andsilicon,andcontainsimpuritiessuchasphosphorous,sulphur,gases,andslag.Theproportionsofthesesubstancesmaybealteredtoachievedifferentproperties,suchasincreasedresistancetowearoncurves.ThestandardconfigurationforNorthAmericanrailresemblesanupsidedownT.ThethreepartsofT-railarecalledthebase,web,andhead.Theflatbaseenabledsuchrailtobespikeddirectlytowoodencrossties;later,railwasplacedonthenow-standardsteeltieplate.Whiletheproportionsandpreciseshapeofrailaresubjecttoconstantanalysisandrefinement,thebasicT-sectionhasbeenstandardsincethemid-19thcentury.WeightThemostcommonwayofdescribingrailisintermsofitsweightperlinearyard(thehistoricBritishunitoflength),whichisafunctionofitscrosssection.Inthelate19thcentury,railwasproducedinarangeofsectionsweighingbetween40and80lbs.peryard.Weightsincreasedovertime,sothatrailrolledtodayweighsbetween112and145lbs.(ThePennsylvaniaRailroad's155-lb.section,usedforatimeafterWorldWarII,wastheheaviestusedintheU.S.)JointedrailsegmentsThelengthofstandardrailshashistoricallybeenrelatedtothelengthofthecarsusedtotransportthem.Fromanearlyrangeof15-20feet,raillengthincreasedwithcarsizeuntilastandardof39feet(easilyaccommodatedbytheonce-common40-footcar)wasreached.Evenwiththeadventoftoday'slongercars,39feethasremainedthestandardforrailowingtolimitationsinsteelmillsandeaseofhandling.Thejointsinrail—itsweakestpoints—canmakeforaroughride,andareexpensivetomaintain.Individualrailsarejoinedwithsteelpiecescalledjoint(orangle)bars,whichareheldinplacebyfourorsixbolts.Today,thesix-bolttype,oncereservedforheavy-dutyapplications,isstandard.Theboltsinajointbararefacedalternatelyoutwardandinwardtoguardagainsttheremotepossibilitythataderailedcar'swheelwouldshearthemalloff,causingtherailstopart.Transitionbetweenrailsoftwodifferentweightsisachievedwithspecialanglebars.Interritorywheretherailsserveasconductorsforsignalsystems,bondwiresmustbeusedatthejointstomaintainthecircuit.WeldedrailThetroublesomenatureofrailjointspromptedthemosteasilyrecognizedadvanceinrailtechnology:theadoptionofcontinuousweldedrail(CWR).Fromitsearlyuseonahandfulofroadsinthe1940's,weldedrailhascometobepreferredforalmostallapplications.Itisproducedbyweldingstandard39-foot(ornewer78-foot)segmentstogetherintoquarter-milelengthsatdedicatedplants.Therailsaretransportedtowherethey'reneededinspecialtrains,whicharepulledslowlyoutfromundertherailwhenitistobeunloaded.Wheninplace,CWRisoftenfield-weldedintoevengreaterlengths.Muchjointedtracksurvivesbecauseofthelonglifespanofevenmoderatelyusedrail,andbecausethespecializedequipmentneededforCWRinstallationisnoteconomicalforshortdistances.ManagingtheexpansionandcontractionthatcomeswithtemperaturechangeisimportantwithCWR.Toavoidexpandingandpotentialbucklingwheninservice,weldedrailislaidwhentemperaturesarehigh(orisartificiallyheated).Railanchorsclippedonatthetieskeeptherailfromgettingshorterasitcontractswithfallingtemperatures.Thusconstrained,itshrinksincrosssection(heightandwidth),butnotinlength.Becauseit'sintension,weldedrailistreatedwithcareduringtrackworkincoldweather.MaintainingandreusingrailUnderheavytraffic,railsgetworndown,althoughtheirlifecanbeextendedbygrindingtheheadbacktothepropercontour.Railnolongersuitedformain-lineusemaystillhavesomelight-dutylifeinitandisoftenrelaidonbranches,spurs,orinyards.Main-trackreductionprojectsarealsosourcesofsuchrelayrail.Whenrailwearisunevenatagivenlocation(suchasacurve),railmaybetransposedfromonesidetoanothertogetmax