Open Rails Steam Locomotive Standard Physics Parameters

Aim - this section describes the basic standard physics parameters required to correctly define a steam locomotive in Open Rails Train Simulator. For advanced physics parameters see the Advanced Steam Setting Parameters.

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Index

General Information

Boiler Parameters

Tender Parameters

Fire Parameters

Steam Cylinder Parameters

Locomotive Gearing Parameters


Note: The default unit of measure (UoM) shown in the "Recommended Input Units" column is the UoM value that OR assumes if no UoM is included in the parameter statement.

ParameterENG or WAGDescriptionRecommended Input UnitsSuggested settingsNew or ExistingTypical Examples
General Information
Type ( x )ENGDescribes the type of locomotiveTextSteam, Diesel, ElectricExistingType ( Steam )
ORTSSteamLocomotiveType ( x )ENGDescribes the type of steam locomotiveTextSimple, Compound, GearedNewORTSSteamLocomotiveType ( Simple )
WheelRadius ( x )ENGRadius of drive wheelsDistance - m, cm, mm, km, in, ft, in/2
Default - m
As per loco specsExistingWheelRadius ( 0.648m )
WheelRadius ( 36in )
ORTSNumberDriveAxles ( x )ENGNumber of driven axles on the locomotive.NumberAs per locomotive SpecsNewORTSNumberDriveAxles ( 4 )
ORTSNumberAxles ( x )WAGNumber of axles on the wagon.NumberAs per wagon SpecsNewORTSNumberAxles ( 4 )
ORTSDriveWheelWeight ( x )ENGTotal weight on the drive wheels of the locomotive.Mass - lbs, kg, t, t-uk, t-us
Default - kg
As per loco specs.NewORTSDriveWheelWeight ( 109.5t-uk )
Sanding ( x )ENGMaximum speed at which sand will be applied to the track.Speed - m/s, mph, kph, km/h, kmph, kmh
Default - m/s
As per loco specs.ExistingSanding ( 25mph )
IsTenderRequired ( x )ENGIndicates whether the locomotive is a tender or tank type of locomotiveTextAs per loco specs:
0 = no tender req'd
1 = tender req'd
ExistingIsTenderRequired ( 1 )
Boiler Parameters
ORTSSteamBoilerType ( x )ENGDescribes the type of boilerTextSaturated, SuperheatedNewORTSSteamBoilerType ( Saturated )
BoilerVolume ( x )ENGVolume of boilerVolumeDefaultFT3 - ft^3, in^3, m^3, l, g-uk, g-us
Default - ft^3
This parameter is not overly critical, and where an actual value is not available, use the appropriate calculator for your engine type.ExistingBoilerVolume ( 220.0ft^3 )
BoilerVolume ( 110.0m^3 )
ORTSEvaporationArea ( x )ENGBoiler evaporation areaAreaDefaultFT2 - ft^2, m^2
Default - ft^2
As per loco specs, or where unknown, use the appropriate calculator for your engine type.NewORTSEvaporationArea ( 2198.0ft^2 )
ORTSEvaporationArea ( 194.0m^2 )
MaxBoilerPressure ( x )ENGMax boiler working pressure (Gauge pressure)PressureDefaultPSI - psi, bar, kPa, inhg
Default - psi
As per loco specsExistingMaxBoilerPressure ( 200psi )
MaxBoilerPressure ( 200kPa )
ORTSSuperheatArea ( x )ENGSuperheating heating areaAreaDefaultFT2 - ft^2, m^2
Default - ft^2
As per loco specsNewORTSSuperheatArea ( 2198.0ft^2 )
ORTSSuperheatArea ( 194.0m^2 )
MaxSteamHeatingPressure ( x )ENGMax pressure in steam heating system for passenger carriages.PressureDefaultPSI - psi, bar, kPa, inhg
Default - psi
As per loco specs.
NB: Normally < 100psi.
ExistingMaxSteamHeatingPressure ( 80.0psi )
ORTSBoilerSurfaceArea ( x )ENGExternal surface area of boiler and firebox for the purposes of radiation of heat losses to the atmosphere.AreaDefaultFT2 - ft^2, m^2
Default - ft^2
As per loco specs.NewORTSBoilerSurfaceArea ( 475.0ft^2 )
ORTSFractionBoilerInsulated ( x )ENGDescribe the fraction of the boiler which has a layer of insulation over it.Number
( < 1.0 )
As per loco specs.NewORTSFractionBoilerInsulated ( 0.86 )
ORTSHeatCoefficientInsulation ( x )ENGHeat coefficient of insulation fitted to boiler.(BTU / ((sq. ft.) / hr.)) / (1 (in. / F))
( Typically a value < 1.0 )
As per insulation specs.NewORTSHeatCoefficientInsulation ( 0.4 )
Locomotive Tender Info
MaxTenderWaterMass ( x )ENGWater in tenderMass - lbs, kg, t, t-uk, t-us
Default - kg
1 uk gal = 10lb
1 us gal = 8.34lb
As per loco specsExisting.
(These values should always be present by default, unless the value has been included in the tender file).
MaxTenderWaterMass ( 36500lb )
MaxTenderWaterMass ( 16000kg )
MaxTenderCoalMass ( x )ENGCoal in tenderMass - lbs, kg, t, t-uk, t-us
Default - kg
As per loco specsExisting.
(These values should always be present by default, unless the value has been included in the tender file).
MaxTenderCoalMass ( 13440lb )
MaxTenderCoalMass ( 6000kg )
ORTSTenderWagonWaterMass ( x )WAGWater in tenderMass - lbs, kg, t, t-uk, t-us
Default - kg
1 uk gal = 10lb
1 us gal = 8.34lb
As per loco specsNew.
(These values can be used to overwrite the above values, or instead of them).
ORTSTenderWagonWaterMass ( 36500lb )
ORTSTenderWagonWaterMass ( 16000kg )
ORTSTenderWagonCoalMass ( x )WAGCoal in tenderMass - lbs, kg, t, t-uk, t-us
Default - kg
As per loco specsNew.
(These values can be used to overwrite the above values, or instead of them).
ORTSTenderWagonCoalMass ( 13440lb )
ORTSTenderWagonCoalMass ( 6000kg )
Fire
ORTSGrateArea ( x )ENGLocomotive fire grate areaAreaDefaultFT2 - ft^2, m^2
Default - ft^2
As per loco specsNewORTSGrateArea ( 2198.0ft^2 )
ORTSGrateArea ( 194.0m^2 )
ORTSFuelCalorific ( x )ENGCalorific value of fuelEnergy Density - btu/lb, kj/kg, j/g
Default - kj/kg
Internet search - for coal use a default value of 13700 btu/lbNewORTSFuelCalorific ( 13700btu/lb )
ORTSFuelCalorific ( 33400kj/kg )
ORTSSteamFiremanMaxPossibleFiringRate( x )ENGMaximum fuel rate that fireman can shovel in an hourMass - lbs, kg, t, t-uk, t-us
Default - kg
Use following as defaults:
UK - 3000lb/h
US - 5000lb/h
Aus - 4200lb/h
New - alternate value to MSTSORTSSteamFiremanMaxPossibleFiringRate( 4200lb/h )
ORTSSteamFiremanMaxPossibleFiringRate( 2000kg/h )
SteamFiremanIsMechanicalStoker ( x )ENGIndicates that the locomotive has a mechanical stoker, and hence a large rate of coal feed.FactorAs per loco specs:
0 = no stoker
1 = stoker
ExistingSteamFiremanIsMechanicalStoker ( 1.0 )
Steam Cylinder
NumCylinders ( x )ENGNumber of steam cylindersFactorAs per loco specsExistingNumCylinders ( 2 )
CylinderStroke ( x )ENGLength of cylinder strokeDistance - m, cm, mm, km, in, ft, in/2
Default - m
As per loco specsExistingCylinderStroke ( 26in )
CylinderStroke ( 0.8m )
CylinderDiameter ( x )ENGDiameter of cylinderDistance - m, cm, mm, km, in, ft, in/2
Default - m
As per loco specsExistingCylinderDiameter ( 21in )
CylinderDiameter ( 0.6m )
LPNumCylinders ( x )ENGNumber of steam LP cylinders (Compound locomotive only)FactorAs per loco specsNewLPNumCylinders ( 2 )
LPCylinderStroke ( x )ENGLength of LP cylinder stroke (Compound locomotive only)Distance - m, cm, mm, km, in, ft, in/2
Default - m
As per loco specsNewLPCylinderStroke ( 26in )
LPCylinderStroke ( 0.8m )
LPCylinderDiameter ( x )ENGDiameter of LP cylinder (Compound locomotive only)Distance - m, cm, mm, km, in, ft, in/2
Default - m
As per loco specsNewLPCylinderDiameter ( 21in )
LPCylinderDiameter ( 0.6m )
Locomotive Gearing
ORTSSteamGearRatio ( a, b )ENGRatio of gearsValueAs per loco specsNewORTSSteamGearRatio ( 2.55, 0.0 )
ORTSSteamMaxGearPistonRate ( x )ENGMax speed of piston in ft/minValue onlyAs per loco specsNewORTSSteamMaxGearPistonRate ( 650 )
ORTSSteamGearType ( x )ENGIndicates whether the locomotive has fixed gearing or selectable gearingFixed, SelectAs per loco specsNewORTSSteamGearType ( Fixed )

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