Rackrailway.docx

Rackrailway.docx

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Rackrailway

Rackrailway

FromWikipedia,thefreeencyclopedia

RackrailwaytrackusingtheLamellasystemrack.

Acograilway,pensandrailsrailway,rack-and-pinionrailwayorrackrailwayisarailwaywithatoothedrackrail,usuallybetweentherunningrails.Thetrainsarefittedwithoneormorecogwheelsorpinionsthatmeshwiththisrackrail.Thisallowsthetrainstooperateonsteepgradients.

Schneebergcograilwaysteamlocomotive,withtiltedboiler,onleveltrack.

Mostrackrailwaysaremountainrailways,althoughafewaretransitrailwaysortramwaysbuilttoovercomeasteepgradientinanurbanenvironment.

ThefirstcograilwaywastheMiddletonRailwaybetweenMiddletonandLeedsinWestYorkshire,England,UK,wherethefirstcommercialsteamlocomotive,Salamanca,ranin1812.Thisusedarackandpinionsystemdesignedandpatentedin1811byJohnBlenkinsop.[1]

functioningoftherackandpinion.

ThefirstmountaincograilwaywastheMountWashingtonCogRailwayintheUSstateofNewHampshire,whichcarrieditsfirstfare-payingpassengersin1868andreachedthesummitofMountWashingtonin1869.ThefirstmountainrackrailwayinEuropewastheVitznau-Rigi-BahnonMountRigiinSwitzerland,whichopenedin1871.Bothlinesarestillrunning.

Racksystems

Anumberofdifferentracksystemshavebeendeveloped.Today,themajorityofrackrailwaysusetheAbtsystem.

Differentracksystems:

fromtheleft,Riggenbach,Strub,AbtandLocher.

Blenkinsop

Thinkingthatthefrictionofmetalwheelsonmetalrailswouldbetoolow,JohnBlenkinsopbuilthislocomotivesfortheMiddletonRailwayin1812witha20teeth,threefeetdiametercogwheel（pinion）ontheleftsidethatengagedinrackteeth（twoteethperfoot）ontheoutersideoftherail,themetal"fishbelly"edgerailwithitssiderackbeingcastallinonepiece,inthreefeet（oneyard）lengths.

Allotherracksystemsplacetherackrailhalfwaybetweentherunningrails.

Blenkinsoprackandpinionwithteethonoutersideofonerailonly-seebetterimageonMiddletonRailwaypage.

Stephenson

GeorgeStephensongroupedthesteepgradientsoneithersideofRainhillandfromLiverpooldowntothewharfs,justincasecablehaulagewasnecessary.Intheevent,onlythewharflineneededcablehaulageforafewdecades.

[edit]Marsh

ThefirstsuccessfulrackrailwayintheUSwastheMountWashingtonCogRailway,developedbySylvesterMarsh.Marshdevelopedandtestedhisracksystemandon10September1861hewasissuedaUSpatentforhisinvention.TheMountWashingtonrailwayopenedin1869,usingMarsh'scentralrackwhichemployedparallelwroughtironanglebars,connectedbyregularlyspacedpins.Thepinionwheelsonthelocomotiveshaddeepteeththatensurethatatleasttwoteethareengagedwiththerackatalltimes-thismeasurehelpsreducethepossibilityofthepinionsridingupandoutoftherack.[1]

Riggenbach

TheRiggenbachracksystemwasinventedbyNiklausRiggenbachworkingataboutthesametimeas,butindependentlyfromMarsh.RiggenbachwasgrantedaFrenchpatentin1863basedonaworkingmodelwhichheusedtointerestpotentialSwissbackers.Duringthistime,theSwissConsultotheUnitedStatesvisitedMarsh'sMountWashingtonCogRailwayandreportedbackwithenthusiasmtotheSwissgovernment.EagertoboosttourisminSwitzerland,thegovernmentcommissionedRiggenbachtobuildarackrailwayupRigiMountain.FollowingtheconstructionofaprototypelocomotiveandtesttrackinaquarrynearBerne,theVitznau-Rigi-Bahnopenedon22May1871.[1]

TheRiggenbachracksystem

TheRiggenbachsystemissimilarindesigntotheMarshsystem.Itusesaladderrack,formedofsteelplatesorchannelsconnectedbyroundorsquarerodsatregularintervals.TheRiggenbachsystemsuffersfromtheproblemthatitsfixedladderrackismorecomplexandexpensivetobuildthantheothersystems.

FollowingthesuccessoftheVitznau-Rigi-Bahn,RiggenbachestablishedtheMaschinenfabrikderInternationalenGesellschaftfürBergbahnen（IGB）-acompanythatproducedracklocomotivestohisdesign.[1]

Strub

TheStrubracksystemwasinventedbyEmilStrubin1896.Itusesarolledflat-bottomrailwithrackteethmachinedintotheheadapproximately100 mmapart.Safetyjawsfittedtothelocomotiveengagewiththeundersideoftheheadtopreventderailments.[1]

Thebest-knownuseoftheStrubsystemisontheJungfraubahninSwitzerland.[1]Itisthesimplestracksystemtomaintainandhasbecomeincreasinglypopular[citationneeded].

TheStrubracksystem

Abt

TheAbtsystemwasdevisedbyRomanAbt,aSwisslocomotiveengineer.AbtworkedforRiggenbachathisworksinOltenandlaterathisIGBracklocomotivecompany.In1885hefoundedhisowncivilengineeringcompany.[1]

Duringtheearly1880s,AbtworkedtodeviseanimprovedracksystemthatovercamethelimitationsoftheRiggenbachsystem.Inparticular,theRiggenbachrackwasexpensivetomanufactureandmaintainandtheswitcheswerecomplex.In1882Abtdesignedanewrackusingsolidbarswithverticalteethmachinedintothem.Twoorthreeofthesebarsaremountedcentrallybetweentherails,withtheteethoffset.Theuseofmultiplebarswithoffsetteethensuresthatthepinionsonthelocomotivedrivingwheelsareconstantlyengagedwiththerack.TheAbtsystemischeapertobuildthantheRiggenbachbecauseitrequiresalowerweightofrackoveragivenlength.HowevertheRiggenbachsystemexhibitsgreaterwearresistancethantheAbt.[1]

Abtracksystem

Abtracksystem

ThefirstuseoftheAbtsystemwasontheHarzbahninGermanywhichopenedin1885.[1]

Thepinionwheelscanbemountedonthesameaxleastherailwheels（asinthepictureatright）,ordrivenseparately.ThesteamlocomotivesontheMountLyellMiningandRailwayCompanyhadseparatecylindersdrivingthepinionwheel.

Locher

TheLocherracksystem,inventedbyEduardLocher,hasgearteethcutinthesidesratherthanthetopoftherail,engagedbytwocogwheelsonthelocomotive.Thissystemallowsuseonsteepergradesthantheothersystems,whoseteethcouldjumpoutoftherack.ItisusedonthePilatusRailway.

Locherracksystem

Lochersetouttodesignaracksystemthatcouldbeusedongradientsassteepas1in2（50%）.TheAbtsystem-themostcommonracksysteminSwitzerlandatthetime-waslimitedtoamaximumgradientof1in4（25%）.Lochershowedthatonsteepergrade,theAbtsystemwaspronetothedrivingpinionover-ridingtherackcausingpotentiallycatastrophicderailments,aspredictedbyDr.Abt.ToovercomethisproblemandallowaracklineupthesteepsidesofMt.Pilatus,Locherdevelopedaracksystemwheretherackisaflatbarwithsymmetrical,horizontalteeth.Horizontalpinionsengagethecentrally-mountedbar,bothdrivingthelocomotiveandkeepingitcenteredonthetrack.

LocherRacksystem（seenfromabove）

Thissystemprovidesverystableattachmenttothetrack,alsoprotectingthecarfromtopplingoverevenundertheseverestcrosswinds.Suchgearsarealsocapabletoleadthecar,soevenflangesonrunningwheelsareoptional.Thebiggestshortcomingofthesystemseemsthattheordinaryrailwayswitchisnotpossibleandatransfertableorothercomplexdevicemustbeusedwhereitisneededtobranchthetrack.

Followingtests,theLochersystemwasdeployedonthePilatusRailwaywhichopenedin1889.NootherpublicrailwayusestheLochersystem,althoughsomeEuropeancoalminesuseasimilarsystemonsteeplygradedundergroundlines.[1]

[edit]Lamella

TheLamellasystem（alsoknownastheVonRollsystem）wasdevelopedbytheVonRollcompanyaftertherolledsteelrailsusedintheStrubsystembecameunavailable.ItisformedfromasinglebladecutinasimilarfashiontotheAbtsystembuttypicallywiderthanasingleAbtbar.TheLamellarackcanbeusedbylocomotivesdesignedforuseontheRiggenbachortheStrubsystemsandsomerailwaysuserackfrommultiplesystems.TheSt.GallenGaisAppenzellRailwayinSwitzerlandhassectionsofRiggenbach,StrubandLamellarack.[1]

Mostoftherackrailwaysbuiltfromthelate20thcenturyonwardshaveusedtheLamellasystem.[1]

Mostoftherackrailwaysbuiltfromthelate20thcenturyonwardshaveusedtheLamellasystem.[1]

JointbetweenRiggenbachandStrub

Rack-and-adhesionsystems/Pureracksystems

Rack-and-adhesionsystemsusethecogdriveonlyonthesteepestsectionsandelsewhereoperateasaregularrailway.Others,thesteeperones,arerack-only.Onthelattertype,thelocomotives'wheelsaregenerallyfree-wheelinganddespiteappearancesdonotcontributetodrivingthetrain.Inthiscasetherackscontinuealsointhehorizontalparts,ifany.

Fell

TheFellmountainrailwaysystemisnotstrictlyspeakingarackrailwaysincetherearenocogswithteeth.Rather,thissystemusesasmoothraisedcentrerailbetweenthetworunningrailsonsteeplineswhichisgrippedonbothsidestoimprovefriction.Trainsarepropelledbywheelsorbrakedbyshoespressedhorizontallyontothecentrerail,aswellasbymeansofthenormalrunningwheels.

[edit]Switches

Railroadswitchatrackrailway（ŠtrbskéPleso,Slovakia）

Rackrailwayswitchesareasvariedasrackrailwaytechnologies,foroptionalracklinessuchastheZentralbahninSwitzerlandandtheWestCoastWildernessRailwayinTasmaniaitisconvenienttoonlyuseswitchesonsectionsflatenoughforadhesion（forexample,onapasssummit）.Othersystemswhichrelyontherackfordriving（withtheconventionalrailwheelsundriven）suchastheDolderbahninZurich,ŠtrbskéPlesoinSlovakiaandtheSchynigePlatterackrailwayinsteadmustswi