[scottb613]

Hi Folks,

Any ORTS steam physics guru's interested in giving my physics files a once over - as a favor ? I'm pretty happy with where they are now - but if I'm missing anything or I did anything wrong - I'd appreciate some tips to do it better... She can pull 30 Bob Boudoin ORTS approved 55 Ton coal hoppers up a 1% grade and maintain between 10mph to 15mph - seems plausible to me...

I've used the "steamlocomotive" site for data and Bill Hobbs great physics spreadsheet v3 to come up with the model...

The one thing that seems a little weak is she might be making too much steam - I can be pretty sloppy with the reverser and not affect boiler pressure a great deal... I did notice the new ORTS_BoilerEfficiency parameter - and I thought that it might be an easy way to throttle back the boiler a bit but it's not a simple setting... I'm not sure that's the right path...

Wheel slippage just seems unrealistic in ORTS in general - at least from the animation aspect - I've read the respective posts I could find - but zero to a thousand rpm's on the animation just spoils it for me - can't get it working better myself... Perhaps some sort of RPM limiter on the animations would help ?

Anyway - any tips or pointers appreciated...

Thanks...

Regards,
Scott

[scottb613]

Hi Folks,

OK - I think I found a gross conceptual error I had on how all this ORTS physics works - I had it my head that since ORTS is capable of reading MSTS values - therefore when ORTS values are introduced - it would take both into account... From my testing and reading more of Peter's great site - that doesn't seem to be the case... My MSTS values outnumbered my ORTS values by far in my configuration - hence the complexity causing some of my confusion - yet when I stripped all the MSTS values out leaving a bare bones minimum ORTS config (vastly simpler) - it didn't seem to impact operation of the locomotive at all... The settings needed for ORTS are so few it's actually scary - I guess everything is derived from a few basic essential settings...

For example - we used to have to provide all kinds of information in MSTS relating to the injectors - there doesn't seem to be one setting in ORTS related to this...

Give ORTS a few basic dimensions on boiler heating surfaces and dimensions - the dimensions of the cylinders - and the weight of the locomotive - it calculates everything else - wow - all the force, power, tractive effort stuff on the fly - they must have put some serious amount of code into this - it seems far simpler than MSTS...

Would anyone know how I can come up with good "Brakes" values for a steam locomotive - what's the process ? They seem to need to be tailored to each locomotive...

And with that - any future work from me is probably going to be ORTS only...

Thanks...

Regards,
Scott

[copperpen]

Peter has a section on brakes in his Physics section on Coalstonewcastle. Turning to the ORTS steam eng file, I was amazed at how small this can be, even smaller if one also uses include files for couplers and brakes. As one of the test crew for the steam code I can confirm that a lot of work went into producing this code and a lot of the performance is obtained by taking the eng file data and combining it with extrapolated data from inbuilt tables. There is also an allowance for minor tuning of performance by altering some of the data in the eng file. The manual gives details where this can be used and includes the working range of the data.


The beauty of the code is that it can use MSTS eng files with no changes, but if one takes a bit of time to make a proper ORTS eng file, the rewards are great.

[steamer_ctn]

scottb613, on 18 March 2019 - 03:28 AM, said:

OK - I think I found a gross conceptual error I had on how all this ORTS physics works

Your revised perception is 100% correct.

A lot of effort went into "simplifying" the steam configuration to try and remove some of the complexity that you have alluded to in the MSTS approach, where content creators needed to search for lots of detailed information, and often do complex calculations (and adjusting parameters away from design values to get the "best outcome").

Thus the design philosophy for the OR steam code has been to create two levels of configuration as follows:
i) BASIC configuration - allows the content creator to configure minimal parameters, which are often easily found for example on Wikipedia. The BASIC configuration should give a reasonable "out of the box" representation of the steam locomotive performance.

ii) ADVANCED configuration - a small number of parameters can be adjusted to fine tune the locomotive to known performance standards such as test reports, etc. See the CTN website for more detail.


The CTN website also has a suggested layout format for ENG and WAG files. It is suggested that use of this format will further simplify the files and make it easier to read by the content creator and other configuration checkers.

scottb613, on 18 March 2019 - 03:28 AM, said:

For example - we used to have to provide all kinds of information in MSTS relating to the injectors - there doesn't seem to be one setting in ORTS related to this...

This is a good example of the "more complex" calculations that are performed internally by OR to save the content provider from having to source this type of information and do complex calculations.

scottb613, on 18 March 2019 - 03:28 AM, said:

Would anyone know how I can come up with good "Brakes" values for a steam locomotive - what's the process ? They seem to need to be tailored to each locomotive...

As Copperpen has suggested the CTN site has some information. Whilst there are some differences between the braking systems on different locomotives, most of the basics will be similar.

In my opinion there are still some basic features missing from the air brakes, such as performance variation as the train length (brake system volume) changes. This feature was added to vacuum braking but hasn't been done for air brakes yet.

[scottb613]

copperpen, on 18 March 2019 - 12:27 PM, said:

The beauty of the code is that it can use MSTS eng files with no changes, but if one takes a bit of time to make a proper ORTS eng file, the rewards are great.

steamer_ctn, on 18 March 2019 - 08:42 PM, said:

Your revised perception is 100% correct.

A lot of effort went into "simplifying" the steam configuration to try and remove some of the complexity that you have alluded to in the MSTS approach, where content creators needed to search for lots of detailed information, and often do complex calculations (and adjusting parameters away from design values to get the "best outcome").

Hi Folks,

Gentlemen - thanks so much for you help and insights... My much revised and streamlined code is as follows - I've been working my way though building this physics model - line by line - using both my source data and Peter's information and calculators available on his great site - there is just so much information there...

If you have a few minutes more - it might be worth while to document someone's trip down this path as a reference for others that come after... I've searched here and haven't found anything like that... My previous builds were all for MSTS and I was fortunate enough to have Bill Hobbs to consult with while making them...

As per Copperpen I looked for the brake data and started work on the WAGON section of the ENG file last night... A few questions came up which I couldn't readily answer - if it's not PRR or NYC obtaining RW source data is extremely difficult...

RE: Middle to Late Model fairly large US Steam Locomotive:

• What's a Direct Admission Valve and should I include it?
  
• How many brake cylinders should I include for the locomotive and tender ?
  
• Should the Emergency Reserve and Auxiliary Reserve be set the same ?

Note: I've massively increased the braking forces - based on the calculators - from what I had initially...

Question: Do the "NumWheels" still come into play here - and IIRC - even though I have "5" - I thought these should represent driving axles ?

Question: Shouldn't overzealous use of locomotive brakes actually lock up the wheels ? I thought that was an issue engineers had to deal with... I won't be able to test my updates until next weekend - so these changes are currently untested...

Question: Can I delete that "derail" data ? I didn't see it referenced in ORTS...

Note: Look at how few settings control steam generation in the "ORTS Boiler" section...

Question: Is there anyway to account for feedwater heaters in the ORTS model ?

Thanks so much - I haven't really hit the ENG Brakes section yet - but - I'll gladly take any tips you care to share... For that matter - if there is more I can delete or possibly some glaring omissions from the entire file - I would appreciate that as well... I think much of that stuff left in my "Brakes Engine" section - that's not brake related - can go...

Regards,
Scott

SIMISA@@@@@@@@@@JINX0D0t______

Comment ( ########## WAGON ########## )
Wagon ( 280consolidation 
	Type ( Engine ) 
	WagonShape ( 280consolidation.S ) 
	Size ( 3.26m 4.81m 13.35m ) 
	CentreOfGravity ( 0m 2.396286m 5m ) 
	Centre ( 0m 0m 0m ) 
	Mass ( 154.85t )
	InertiaTensor ( Box ( 3.26m 4.81m 13.30m ) )
	WheelRadius ( 0.4572m ) 
	NumWheels ( 5 )
	
Comment ( ##### COUPLING ##### )	
	Coupling ( 
		Type ( Bar ) 
		Spring ( 
			Stiffness ( 1.2e6N/m 1.2e6N/m ) 
			Damping ( 4.65e5N/m/s 4.65e5N/m/s ) 
			Break ( 1.8e7N 1.8e7N ) 
			r0 ( 0cm 5cm ) 
		) 
		CouplingHasRigidConnection ( 1 ) 
		Velocity ( 0.1m/s ) 
	) 
	Coupling ( 
		Type ( Automatic ) 
		Spring ( 
			Stiffness ( 5.0e5N/m 1.0e7N/m ) 
			Damping ( 1.6e6N/m/s 1.0e7N/m/s ) 
			Break ( 1.2e7N 1.2e7N ) 
			r0 ( 0cm 15cm ) 
		) 
		Velocity ( -0.1m/s ) 
	) 
	DerailRailHeight ( 10cm ) 
	DerailRailForce ( 376kN ) 
	DerailBufferForce ( 400kN ) 

Comment ( ##### ORTS FCALC FRICTION ##### )
	ORTSBearingType ( Friction )
	ORTSDavis_A ( 3155.30lb )
	ORTSDavis_B ( 4.6455lbf/mph )
	ORTSDavis_C ( 0.259200lbf/mph^2 )
	CentreOfGravity ( 0m 2m 0m ) 
	ORTSTrackGauge ( 4ft 8.5in )
	ORTSUnbalancedSuperelevation ( 6in )
	ORTSRigidWheelbase ( 17.0ft 5.0in )

Comment ( ##### BRAKES WAGON ##### )
	BrakeEquipmentType ( "Triple_valve, Auxilary_reservoir, Emergency_brake_reservoir, Handbrake" ) 
	BrakeSystemType ( "Air_single_pipe" ) 
	MaxBrakeForce ( 516.63kN )
	MaxHandbrakeForce ( 137.77kN ) 
	TripleValveRatio ( 2.5 ) 
	MaxApplicationRate ( 50 ) 
	MaxReleaseRate ( 50 ) 
	MaxAuxilaryChargingRate ( 20 ) 
	EmergencyResChargingRate ( 20 ) 
	EmergencyResCapacity ( 4.963ft^3 )
	EmergencyBrakeResMaxPressure ( 90 )
	BrakeCylinderPressureForMaxBrakeBrakeForce ( 50 )
	ORTSDirectAdmissionValve (0)
	ORTSAuxilaryResCapacity ( 4.963ft^3 )
	ORTSNumberBrakeCylinders ( 1 )
	ORTSBrakeCylinderSize ( 18in )
	
Comment ( ##### LIGHTS ##### )
	Lights ( 2 
		Light ( 
			comment ( Sphere of light )
			Type ( 1 ) 
			Conditions ( 
				Headlight ( 3 ) 
				Unit ( 2 ) 
				TimeOfDay ( 2 ) 
			) 
			Cycle ( 0 ) 
			FadeIn ( 0.5 ) 
			FadeOut ( 0.5 ) 
			States ( 1 
				State ( 
					Duration ( 0.0 ) 
					LightColour ( DDF0E296 ) 
					Position ( 0.0 3.75 6.0 ) 
					Transition ( 0 ) 
					Radius ( 300.0 ) 
					Angle ( 25.0 ) 
				) 
			) 
		) 
		Light ( 
			comment ( HEAD LIGHT DISK )
			Type ( 0 ) 
			Conditions ( 
				Headlight ( 3 ) 
				Unit ( 2 ) 
			) 
			FadeIn ( 0.5 ) 
			FadeOut ( 0.5 ) 
			Cycle ( 0 ) 
			States ( 1 
				State ( 
					Duration ( 0.0 ) 
					LightColour ( DDF0E296 ) 
					Position ( 0 3.2 6.00 ) 
					Azimuth ( -5.0 0.0 5.0 ) 
					Transition ( 0 ) 
					Radius ( 0.8 ) 
				) 
			) 
		) 
	) 
	
Comment ( ##### MISC WAGON ##### )
	Sound ( "Mik-h-eng.sms" ) 
	FreightAnim ( crew.s 1 1 ) 
)


Comment ( ########## ENGINE ########## )
Engine ( 280consolidation 
	Wagon ( 280consolidation ) 
	Type ( Steam )  
	ORTSSteamLocomotiveType ( Simple )
	ORTSDriveWheelWeight ( 283800lb  )
	IsTenderRequired ( 1 ) 
	WheelRadius ( 0.775m )
	NumWheels ( 4 ) 

Comment ( ##### ORTS BOILER ##### )
	ORTSSteamBoilerType ( Superheated )
	ORTSEvaporationArea ( "3607*(ft^2)" )
	ORTSSuperheatArea ( "924*(ft^2)" )
	MaxBoilerPressure ( 220psi ) 
	BoilerVolume ( "666.5*(ft^3)" ) 

Comment ( ##### ORTS CYLINDER ##### )
	NumCylinders ( 2 ) 
	CylinderStroke ( 27in ) 
	CylinderDiameter ( 32in ) 
	ORTSCylinderEfficiencyRate ( 1.0 )
	
Comment ( ##### ORTS FIRE ##### )
	ORTSFuelCalorific ( 12500btu/lb )
	ORTSGrateArea ( "100.0*(ft^2)" )

Comment ( ##### ORTS FUEL ##### )
	MaxTenderCoalMass ( 32000lb ) 
	MaxTenderWaterMass ( 125000lb )
	ORTSSteamFiremanMaxPossibleFiringRate ( 5000 lb/h )
	SteamFiremanIsMechanicalStoker ( 1.0 )

Comment ( ##### EFFECTS ##### )	
	Effects ( 
	SteamSpecialEffects ( 
		StackFX ( 0 5.1 3.8 0 1 0 0.25 ) 
		WhistleFX ( -0.58 4.65 0 0 1 0 0.1 ) 
		SafetyValvesFX ( 0 4.8 -1.2 0 1 0 0.1 ) 
		CylindersFX ( -1.496 0.464 3.8 -1 0 -0.5 0.15 ) 
		CylindersFX ( 1.496 0.464 3.8 1 0 -0.5 0.15 ) 
		) 
	) 

Comment ( ##### ORTS BRAKES ##### )
	AirBrakesAirCompressorPowerRating ( 3 ) 
	AirBrakesMainMinResAirPressure ( 0 ) 
	AirBrakesMainMaxAirPressure ( 125 ) 
	AirBrakesMainResVolume ( 15 ) 
	AirBrakesCompressorRestartPressure ( 110 ) 
	AirBrakesAirUsedPerPoundsOfBrakePipePressure ( .5 ) 
	AirBrakesHasLowPressureTest ( 1 ) 
	ORTSMainResChargingRate ( 0.575 )
	
Comment ( ##### BRAKES ENGINE ##### )
	TrainBrakesControllerMinPressureReduction ( 6 )
	TrainBrakesControllerMaxReleaseRate ( 1 ) 
	TrainBrakesControllerMaxApplicationRate ( 2 ) 
	TrainBrakesControllerEmergencyApplicationRate ( 7 ) 
	TrainBrakesControllerMinSystemPressure ( 0 ) 
	TrainBrakesControllerMaxSystemPressure ( 90 ) 
	TrainBrakesControllerEmergencyBrakeTimePenalty ( 60 ) 
	TrainBrakesControllerFullServicePressureDrop ( 30 ) 
	EngineBrakesControllerMinPressureReduction ( 6 )
	EngineBrakesControllerHasProportionalBrake ( 1 ) 
	EngineBrakesProportionalBrakeLag ( 1 ) 
	EngineBrakesControllerMaxApplicationRate ( 1.8 ) 
	EngineBrakesControllerMaxReleaseRate ( 1.8 ) 
	EngineBrakesControllerEmergencyApplicationRate ( 2.8 ) 
	EngineBrakesControllerMinSystemPressure ( 0 ) 
	EngineBrakesControllerMaxSystemPressure ( 90 ) 
	EngineBrakesControllerEmergencyBrakeTimePenalty ( 60 ) 
	EngineBrakesControllerFullServicePressureDrop ( 30 ) 
	EngineBrakesControllerDirectControlExponent ( 1 ) 
	BrakesEngineBrakeType ( "Air_single_pipe" ) 
	BrakesTrainBrakeType ( "Air_single_pipe" ) 
	BrakesEngineControllers ( "Hand, Train,Independent" ) 
	SteamSmallestCutoff ( .2 ) 
	NumberOfDamperSteps ( 4 ) 
	RegulatorValveType ( Single_port ) 
	RegulatorMainValveInitialOpenning ( 0.1 ) 
	RegulatorMainValveExponent ( 1 )
	SteamBlowerEffectExponent ( 0.9 ) 
	SteamBlowerEfficiencyExponent ( 1.1 ) 
	SteamBlowerMaxSteamUsageRate ( 500 ) 
	comment ( lbs/h )
	SteamBlowerMaxProportionOfBlastEffect ( 0.25 ) 
	SteamSmokeUnitsPerPoundOfFuel ( 6.3 )
	
Comment ( ##### PLAYER CONTROLS ##### )
	EngineControllers ( 
		comment ( Engine controls )
		Regulator ( 0 1 0.025 0 
			NumNotches ( 0 
			) 
		) 
		Cutoff ( -0.8 0.8 0.025 0 
			NumNotches ( 0 
			) 
		) 
		Brake_Train ( 0 1 0.025 0.6 
			NumNotches ( 5 
				Notch ( 0 0 TrainBrakesControllerReleaseStart ) 
				Notch ( 0.2 0 TrainBrakesControllerRunningStart ) 
				Notch ( 0.3 0 TrainBrakesControllerSelfLapStart ) 
				Notch ( 0.4 1 TrainBrakesControllerApplyStart ) 
				Notch ( 1 0 TrainBrakesControllerEmergencyStart ) 
			) 
		) 
		Brake_Engine ( 0 1 0.1 1 
			NumNotches ( 2 
				Notch ( 0 0 EngineBrakesControllerReleaseStart ) 
				Notch ( 0.1 1 EngineBrakesControllerApplyStart ) 
			) 
		) 
		FireDoor ( 0 1 1 0 
			NumNotches ( 0 
			) 
		) 
		Sanding ( 0 1 0 ) 
		Blower ( 0 1 0.1 0.1 
			NumNotches ( 0 
			) 
		) 
		HeatingTap ( 0 1 0.025 0 
			NumNotches ( 0 
			) 
		) 
		Shovel ( 0 1 0.1 0 
			NumNotches ( 0 
			) 
		) 
		DampersFront ( 0 1 0.1 1 
			NumNotches ( 0 
			) 
		) 
		DampersBack ( 0 1 0.1 0 
			NumNotches ( 0 
			) 
		) 
		Injector1Steam ( 0 1 0 ) 
		Injector2Steam ( 0 1 0 ) 
		Injector1Water ( 0 1 0.2 0 
			NumNotches ( 0 
			) 
		) 
		Injector2Water ( 0 1 0.2 0 
			NumNotches ( 0 
			) 
		) 
		CylinderCocks ( 0 1 0 ) 
		Whistle ( 0 1 0 ) 
		BellToggle ( 0 1 0 ) 
		SmallEjectorOrCompressor ( 0 1 1 ) 
		HeadLights ( 0 1 0 ) 
	) 
	
Comment ( ##### MISC ENGINE ##### )
	Sound ( "Mik-h-cab.sms" ) 
	Name ( "Wrx LHR Consolidation" ) 
	CabView ( sps_700.cvf ) 
	HeadOut ( 1.95 3.5 -6.2 )
	Description ( "The description of the engine that the user will see.\n"+
        " \n" ) 
	EngineOperatingProcedures ( "The operating procedures for the engine.\n"+
        " \n" ) 
) 

[wellsburg]

Scott,

There are more visual effects that can be added to the .eng Effects section as a result of the loco physics.

Two sets of Cylinder1FX and Cylinder2FX can represent the cylinder petcock blow-downs front and rear, left and right. Makes a distinct visual effect when C is pressed.

Injectors2FX ( fireman's side ) does function in OR when the injector ( automatically ) replenishes the boiler. Can represent the injector drain.

GeneratorFX can represent the turbo generator exhaust. Active continuously.

Multiple GeneratorFX can be set to represent various steam leaks.

CompressorFX can represent the air pump exhaust when the pump is running. Active when air pump is operating.

There are other special effects for wagons that can be inserted into the Wagon section of the .eng file. Such as HeatingHoseFX that can also represent steam leaks.
Refer to Coals To Newcastle Visual Effects section.

Such an awesome loco deserves a full complement of visual effects.

Mike

[scottb613]

Hi Folks,

Oh - for the record - she’s an Anthraciite burner which is refelected in the fuel value I provided - but could such a large grate area skew the results of the generic steam model ? One RW comment I did come across was “they tended to be a bit short on steam when climbing long steep grades”... The model - as I have it defined above seems to have a vast surplus of steam no matter how sloppy I am with the reverser while driving it... I did play with adjusting the “boiler volume” in another test eng file - then I came across your note mentioning boiler volume has little effect on the ORTS model - I suspect the “boiler efficiency” may be a better way to manipulate this - yet I have no RW data to populate it...

Thanks...

Regards,
Scott

NOT MY IMAGE

Attached thumbnail(s)

• 

[scottb613]

wellsburg, on 19 March 2019 - 12:04 PM, said:

Scott,

Such an awesome loco deserves a full complement of visual effects.

Mike

Hi Mike,

Hah - that’s fantastic - we can now make steam locomotives that have plenty of steam - thanks for the heads up - sounds like fun getting these new effects to work - I’ll be sure to add them...

Thanks for the complement as well...

Regards,
Scott

[steamer_ctn]

Hi Scott,
To answer a few of your questions:

scottb613, on 19 March 2019 - 07:48 AM, said:

Question: Do the "NumWheels" still come into play here - and IIRC - even though I have "5" - I thought these should represent driving axles ?

Yes they do, and as you rightly suggest it is actually the number of axles.

scottb613, on 19 March 2019 - 07:48 AM, said:

Question: Shouldn't overzealous use of locomotive brakes actually lock up the wheels ? I thought that was an issue engineers had to deal with... I won't be able to test my updates until next weekend - so these changes are currently untested...

Yes, wheel skid is possible if too much braking force is applied to the wheels.

scottb613, on 19 March 2019 - 07:48 AM, said:

Question: Can I delete that "derail" data ? I didn't see it referenced in ORTS...

Yes

scottb613, on 19 March 2019 - 07:48 AM, said:

Question: Is there anyway to account for feedwater heaters in the ORTS model ?

Not separately at the moment, but the current code seems to cope ok without the need to correct for it.

scottb613, on 19 March 2019 - 12:10 PM, said:

Oh - for the record - she’s an Anthraciite burner which is refelected in the fuel value I provided - but could such a large grate area skew the results of the generic steam model ? One RW comment I did come across was “they tended to be a bit short on steam when climbing long steep grades”... The model - as I have it defined above seems to have a vast surplus of steam no matter how sloppy I am with the reverser while driving it... I did play with adjusting the “boiler volume” in another test eng file - then I came across your note mentioning boiler volume has little effect on the ORTS model - I suspect the “boiler efficiency” may be a better way to manipulate this - yet I have no RW data to populate it...

From my recollection Anthracite coal burnt with a lower calorific value, and hence a larger grate area would be required to produce the same amount of heat.

To adjust steam production try adjusting the ADVANCED parameter controlling boiler evaporation.

[dajones]

I think the reason for the larger firebox was to allow waste anthracite coal (dust and small pieces) to be burned slowly so that it wouldn't be lifted off the grate. So it should have a lower draft compared to a normal firebox with the same grate area. I'm not sure how best to model that. You should be able to find a description by googling "wootten firebox".

Doug