Elvas Tower: Wishes for improvement of braking systems - Elvas Tower

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Wishes for improvement of braking systems Adding and correcting of features Rate Topic: -----

#311 User is offline   Weter 

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Posted 18 February 2023 - 10:21 AM

Axle-driven compressors and steam compressors animation (I'm dreaming too much, certainly)
About ones, mechanical-driven from diesel, they rotated continiously, but low MR pressure turned their valves "on", so they started to push air to MR. Normal MR pressure causes their valves turn constantly open, so cylinders become "decompressed".

#312 User is offline   darwins 

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Posted 19 February 2023 - 12:28 AM

Quote

The brake release pedal of the locomotive. If it is held down when braking with the train brake, the locomotive does not brake.


Thanks for that.

It is probably a "bleed off valve" that releases the loco brakes by releasing air from the auxiliary reservoir. (Knorr type system.)

My request is please can we have working "bleed off valves" or "vacuum release valves" in locomotive cab views. As far as keyboard shortcut goes then perhaps the existing "bail off" key can be used - but the way it works would depend on the brake system installed. For some systems is opens the auxiliary reservoir or vacuum reservoir, where for others it directly opens the brake cylinder. In either case the final effect is the same though!

#313 User is offline   Traindude 

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Posted 14 March 2023 - 09:19 PM

Sorry to bump this thread, but I have another idea for a potential feature: Gradual Opening and Closing of Angle Cocks

I recently took a switching class at my local railway museum, and in that class, I was told that the museum strongly discouraged opening an angle cock from "fully closed" to "fully opened" suddenly. This is because the near-instant surge in airflow in the brake pipe ("dynamiting the air" as they called it) would cause such a severe pressure drop in the brake pipe and the locomotive would take longer to "recover the air" and restore the proper pipe pressure.

Instead, we were instructed to open the angle cocks slowly and gradually, in this manner:
1) Slowly open the angle cock until a hissing air sound is heard, then keep the angle cock in this position momentarily. This means the brake pipe is being charged.
2) The air hiss will gradually fade out and then stop when the brake pipe pressure has been equalized. It is now safe to open the angle cock to the fully opened position, and the locomotive can recover the air in much less time than if the angle cock were to be fully opened suddenly.

Not sure if this can potentially be implemented in ORTS, but I'm just throwing it out there.

#314 User is offline   vince 

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Posted 15 March 2023 - 08:02 AM

A slow release of the air in the pipe or a quick release all result in no air in the pipe.

I fail to see why a quick release would cause a problem or exactly how this causes a problem?
vince

#315 User is offline   Weter 

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Posted 15 March 2023 - 01:20 PM

Hello. Didn't see You for a quite long period.
Quick pressure equalization would cause sudden pressure drop.
Air distributors often have "emergency" mode, which is triggered by very quick pressure drop in BP (as if hoses are disconnected, stop-alve opened on some car, or driver's valve set on Emergency position. Once triggered, distributor starts release air by itself, so discharge are faster and taking place on every car of the train, rather on leading locomotive only. So all cars apply brakes more synchronous, than they would, when only driver's alve discharges BP. This helps to prevent car squeeeze of een derailment, as if front cars brake already, when the rear part of train is still coasting and bumping into front part.

#316 User is offline   Traindude 

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Posted 08 April 2023 - 02:54 PM

I was looking at the service manuals for the Amtrak Superliner passenger cars, and I noticed something interesting: Their braking systems seem to be a mix of Twin Pipe and EP, here are some excerpts from the service manual, which can be read in full here:

Attached Image: suplnrbrk4.jpg
Attached Image: suplnrbrk2.jpg
Attached Image: suplnrbrk3.jpg
Attached Image: suprlnrbrk1.jpg

The fact that the cars have a Main Reservior line in addition to the Brake Pipe would suggest that they be configured in ORTS as a twin-pipe system, but with the electro-pneumatic magnet valves (which apparently provide instant application/release, so one does not have to wait for the change in pipe pressure to travel the length of the pipe), would this be configured as an EP system? Which is it?

Also, something to think about, is the use of brake status as a lighting condition:
Attached Image: suplnrbrkind.jpg

Apparently, all Amtrak locomotive-hauled stock has these (Superliners, Amfleet, Viewliner, etc). An example of how I would define it is with a "Brake" lighting condition with the following variables: (1 = brake released, 2 = brake applied, 0 = ignore):
            Light	(
			comment( Brake Released (green)light dim, front  )
			Type		( 0 )
			Conditions	(
				Headlight ( 2 )
				Unit ( 0 )
                                Brake ( 1 )
			)
			FadeIn	( 0.5 )
			FadeOut	( 0.5 )
			Cycle		( 0 )
			States	(	1
				State	(
					Duration ( 0.0 )
					LightColour ( ff00ff00 )
					Position ( -1.58 2.595 -11.01 )
					Azimuth ( 0 0 0 )
					Transition ( 0 )
					Radius ( .15 )
					)
				)
			)
                  Light	(
			comment( Brake Applied (yellow) light dim, front )
			Type		( 0 )
			Conditions	(
				Headlight ( 2 )
				Unit ( 0 )
                                Brake ( 2 )
			)
			FadeIn	( 0.5 )
			FadeOut	( 0.5 )
			Cycle		( 0 )
			States	(	1
				State	(
					Duration ( 0.0 )
					LightColour ( ffffff33 )
					Position ( -1.575 2.645 -11.01 )
					Azimuth ( 0 0 0 )
					Transition ( 0 )
					Radius ( .15 )
					)
				)
			)

These can also be potentially used on interurban, light rail vehicle and streetcar models (which often share the road with vehicular traffic) to simulate brake lights. Additional brake-related lighting parameters could include:
ORTSBrakeLightReleaseStateCylinderPressureThreshold ( 10psi )
ORTSBrakeLightAppliedStateCylinderPressureThreshold ( 25psi )
ORTSDoesHandbrakeInfluenceBrakeLightState ( 1 )



I'm unaware if there are already provisions for this, but if there aren't, are they worth implementing in the future?

#317 User is offline   Weter 

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Posted 08 April 2023 - 03:48 PM

Very good idea.
Trams and subway carriages sometimes have such lights too.
Door open. Brake applied, overload relay shut off lights on each side, for instance.

WRT EP, IIRC currently any EP (brake equipment() entry of wagon section) need twin pipe (brake type () entry) to be specified, for working.

#318 User is offline   darwins 

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Posted 09 April 2023 - 02:05 AM

As Weter says this brake system is correctly defined in Open Rails as "EP". The normal EP system in OR is the standard UIC twin pipe EP system where there is reduction in brake pipe pressure in parallel with the EP application on each vehicle.

In ORTS I think this would be something like the following. You may need to make some adjustments to suit.

Locomotive - Wagon Section

MaxBrakeForce ( 145kN ) Comment ( * braked at 50% WWO from 0 to 145km/h; braked at 34% WWO 145 to 200 km/h * )
MaxHandbrakeForce ( 30kN )
BrakePipeVolume ( 0.52ft^3 )
ORTSNumberBrakeCylinders ( 2 )
ORTSBrakeCylinderSize ( 12in )

BrakeEquipmentType ( Distributing_valve, Handbrake ) Comment ( should use modern proportional valve )
BrakeSystemType ( "EP" )
EmergencyResVolumeMultiplier ( 1.0 )
MaxAuxilaryChargingRate ( 0.4psi/s )
EmergencyResChargingRate ( 0.4psi/s )
EmergencyResCapacity ( 2.064ft^3 )
BrakeCylinderPressureForMaxBrakeBrakeForce ( 60psi )

Comment ( UIC Locomotive Air_single_pipe – Passenger Braking Mode )
MaxReleaseRate ( 0.44bar/s )
MaxApplicationRate ( 1.2bar/s )

Comment ( composite disc brakes - based on CoFren 2150 curve )
ORTSBrakeShoeFriction (
0   0.50  
40  0.42
80  0.38
120 0.36
160 0.34  
200 0.33 )

ORTSWheelBrakeSlideProtection ( 1 )
ORTSWheelBrakesSlideProtectionLimitDisable ( 1 )



Locomotive - Engine Section

BrakesEngineBrakeType ( "EP_brake" )
BrakesTrainBrakeType ( "EP" )

Comment ( == Compressor, Reservoir and General == )
AirBrakesMainMaxAirPressure( 150psi )
AirBrakesCompressorRestartPressure( 130psi )
ORTSBrakePipeChargingRate ( 60psi/s )
AirBrakesMainResVolume( 85ft^3 )
ORTSMainResChargingRate ( 0.326 )
AirBrakesIsCompressorElectricOrMechanical( 1 )
ORTSCompressorIsMUControlled( 1 )

ORTSBrakePipeTimeFactor ( 0.005 )
ORTSBrakeEmergencyTimeFactor ( 0.1 )
ORTSBrakeServiceTimeFactor ( 0.25 )
TrainPipeLeakRate ( 0.0833 )

Comment ( == Automatic Brake valve - Train == )
TrainBrakesControllerMaxSystemPressure ( 110psi )
TrainBrakesControllerMaxReleaseRate ( 1.0psi/s )
TrainBrakesControllerMaxQuickReleaseRate ( 4.0psi/s )
TrainBrakesControllerMaxApplicationRate ( 3.5psi/s ) Comment ( EQ reservoir to drop from 110psi to 90psi in 5 to 6 seconds )
ORTSTrainBrakesControllerSlowApplicationRate ( 1.3psi/s )
TrainBrakesControllerEmergencyApplicationRate ( 48psi/s )
TrainBrakesControllerFullServicePressureDrop ( 24psi )
TrainBrakesControllerMinPressureReduction ( 10psi )

Comment ( == Independent Brake valve - Engine == )
EngineBrakesControllerMaxSystemPressure ( 64psi )
EngineBrakesControllerMaxReleaseRate ( 12psi/s )
EngineBrakesControllerMaxApplicationRate ( 8psi/s )
EngineBrakesControllerEmergencyApplicationRate ( 24psi/s )
EngineBrakesControllerFullServicePressureDrop ( 0psi )
EngineBrakesControllerMinPressureReduction ( 1psi )

    DynamicBrakesMinUsableSpeed( 3.5 )
    DynamicBrakesMaximumEffectiveSpeed( 27 )
    DynamicBrakesMaximumForce( 388.4kN )
    DynamicBrakesResistorCurrentLimit ( 950 )
    DynamicBrakesCutInSpeed( 5.5 )
    DynamicBrakesMaxAirBrakePressure ( 50 )
    DynamicBrakesFadingSpeed( 7 )
    DynamicBrakesDelayTimeBeforeEngaging ( 8 )
    DynamicBrakesMaximumSpeedForFadeOut ( 560 )
    DynamicBrakesEffectAtMaximumFadeOut( 0 )
    DynamicBrakesHigherSpeedCurveExponent( 11.5 )
    DynamicBrakesLowerSpeedCurveExponent( 0.95 )
    DynamicBrakesNumberOfControllerNotches( 1 )
    DynamicBrakeHasAutoBailOff( 1 )



Locomotive - Controllers section

Comment ( Westinghouse 26L EP Passenger mode )
Brake_Train ( 0 1 0.1 0.1
NumNotches ( 5
Notch ( 0.0  0 TrainBrakesControllerReleaseStart ) Comment ( RELEASE / RUNNING )
Notch ( 0.1  1 TrainBrakesControllerEPApplyStart ) Comment ( MINIMUM REDUCTION >>> FULL SERVICE )
Notch ( 0.8  0 TrainBrakesControllerSuppressionStart ) Comment ( SUPPRESSION )
Notch ( 0.9  0 TrainBrakesControllerNeutralHandleOffStart ) Comment ( NEUTRAL HANDLE OFF )
Notch ( 1.0  0 TrainBrakesControllerEmergencyStart )Comment ( EMERGENCY ) ) )

Brake_Engine ( 0 1 0.1 0.2
NumNotches ( 3 
Notch( 0.0 0 EngineBrakesControllerBailOffStart ) ( RELEASE* )
Notch( 0.1 0 EngineBrakesControllerReleaseStart ) ( RUNNING )
Notch ( 0.2 1 EngineBrakesControllerContinuousServiceStart )  Comment ( APPLY) ) )



CabCar - Wagon section ( and passenger cars )

MaxBrakeForce ( 45kN ) Comment ( * braked at 50% WWO from 0 to 145km/h; braked at 34% WWO 145 to 200 km/h * )
MaxHandbrakeForce ( 30kN )
BrakePipeVolume ( 0.52ft^3 )
ORTSNumberBrakeCylinders ( 2 )
ORTSBrakeCylinderSize ( 12in )

BrakeEquipmentType ( Triple_Valve, Auxiliary_Reservoir, Handbrake )
BrakeSystemType ( "EP" )
EmergencyResVolumeMultiplier ( 1.0 )
MaxAuxilaryChargingRate ( 0.4psi/s )
EmergencyResChargingRate ( 0.4psi/s )
EmergencyResCapacity ( 2.064ft^3 )
BrakeCylinderPressureForMaxBrakeBrakeForce ( 60psi )

Comment ( UIC Passenger car EP_brake )
MaxReleaseRate ( 0.84bar/s )
MaxApplicationRate ( 1.1bar/s )

Comment ( composite disc brakes - based on CoFren 2150 curve )
ORTSBrakeShoeFriction (
0   0.50  
40  0.42
80  0.38
120 0.36
160 0.34  
200 0.33 )

ORTSWheelBrakeSlideProtection ( 1 )
ORTSWheelBrakesSlideProtectionLimitDisable ( 1 )



Cab Car - Engine Section

BrakesTrainBrakeType ( "EP" )

ORTSBrakePipeTimeFactor ( 0.005 )
ORTSBrakeEmergencyTimeFactor ( 0.1 )
ORTSBrakeServiceTimeFactor ( 0.25 )
TrainPipeLeakRate ( 0.0833 )

Comment ( == Automatic Brake valve - Train == )
TrainBrakesControllerMaxSystemPressure ( 110psi )
TrainBrakesControllerMaxReleaseRate ( 1.0psi/s )
TrainBrakesControllerMaxQuickReleaseRate ( 4.0psi/s )
TrainBrakesControllerMaxApplicationRate ( 3.5psi/s ) Comment ( EQ reservoir to drop from 110psi to 90psi in 5 to 6 seconds )
ORTSTrainBrakesControllerSlowApplicationRate ( 1.3psi/s )
TrainBrakesControllerEmergencyApplicationRate ( 48psi/s )
TrainBrakesControllerFullServicePressureDrop ( 24psi )
TrainBrakesControllerMinPressureReduction ( 10psi )



CabCar - Controllers section

Comment ( Westinghouse 26L EP Passenger mode )
Brake_Train ( 0 1 0.1 0.1
NumNotches ( 5
Notch ( 0.0  0 TrainBrakesControllerReleaseStart ) Comment ( RELEASE / RUNNING )
Notch ( 0.1  1 TrainBrakesControllerEPApplyStart ) Comment ( MINIMUM REDUCTION >>> FULL SERVICE )
Notch ( 0.8  0 TrainBrakesControllerSuppressionStart ) Comment ( SUPPRESSION )
Notch ( 0.9  0 TrainBrakesControllerNeutralHandleOffStart ) Comment ( NEUTRAL HANDLE OFF )
Notch ( 1.0  0 TrainBrakesControllerEmergencyStart )Comment ( EMERGENCY ) ) )

Brake_Engine ( 0 1 0.1 0.2
NumNotches ( 3 
Notch( 0.0 0 EngineBrakesControllerBailOffStart ) ( RELEASE* )
Notch( 0.1 0 EngineBrakesControllerReleaseStart ) ( RUNNING )
Notch ( 0.2 1 EngineBrakesControllerContinuousServiceStart )  Comment ( APPLY) ) )


#319 User is offline   Weter 

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Posted 09 April 2023 - 02:49 AM

Hello, Darwin.
You've really have surprised me with
ORTSNumberBrakeCylinders ( 2 )
ORTSBrakeCylinderSize ( 12in )

Didn't expect, these parameters exist.
What them for (we used triple valve ratio before, for referring dependencies between BP pressure drop and final BC pressure)?
ORTSCompressorIsMUControlled ( 1 )
What is it?
EngineBrakesControllerBailOffStart
Is it functioning?

#320 User is offline   darwins 

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Posted 09 April 2023 - 02:53 AM

View PostWeter, on 09 April 2023 - 02:43 AM, said:

Hello, Darwin.
You've really have surprised me with

Didn't expect, these parameters exist.
What them for (we used triple valve ratio before, for referring dependencies between BP pressure drop and final BC pressure)?


I might have surprised myself. http://www.elvastower.com/forums/public/style_emoticons/default/sweatingbullets.gif Trying to remember now if these are the right parameters for the locomotive (which would not have a conventional triple valve and auxiliary reservoir) when it has Distributing_valve. @Cesar?
In any case I think the cab car and passenger car with triple valves and auxiliary reservoirs would use the previous calculation anyway, so should include triple_valve ratio instead.

Also those parameters are required for all vehicles with vacuum brakes. AFAIK EngineBrakesControllerBailOffStart is now functional. The compressor is MU controlled is mostly for multiple unit trains so that compressors share the load, it causes all compressors on the train to start and stop at the same time.

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