[eugenR]

In Manual charpter 7.4.11 in the last section is written:
In Open Rails, opening the bleed valve on a car or group of cars performs two functions: it vents the air
pressure from the brake system of the selected cars, and also bypasses the air system around the cars if
they are not at the end of the consist so that the rest of the consist remains connected to the main system.

In the Route Marias Pass in the activity "Kesselwagenzug (Train with 2xDash9+37 Oilcars) I can open at any car the bleed valve and the brakesystem of this car will be bypassed as described above.

If I will do the same with the most of my trains this procedure will set the triple-valve to emergency and the brake pipe of the whole train is loosing the pressure.

With many test I have found the parameter with the most influence of this faulty behavior is in the file us2chemicar.wag the parameter MaxAuxilaryChargingRate( 5 )

If I change this parameter to ( 20 ) the bypass is no more working. I have found in the wag-files of many of my trains MaxAuxilaryChargingRate( 35 ), the reason because bypassing is not working with this trains. Can you have a look on this behavior, please?

Regards
EugenR

[eugenR]

Same Problem with the original Oiltrain Marias Pass with MaxAuxilaryChargingRate( 5 )

If I open the bleed valve of 3 cars (4,6,8) of the train, the TripleValve is switching to Emergency:


If I open the bleed valve of a forth (4,6,8,10) car the brake pipe is loosing the airpressure by about 1 psi/s:

[edwardk]

The brake parameters I am using in my wagon files are from MSTS and up to this point, not changed for OR. The original parameter used for MaxAuxilaryChargingRate() is 1.69. With this, I was able to open up the bleed valve on 2 cars in the middle of the consist with no issues. I then changed MaxAuxilaryChargingRate() to 5.69 and still had no issues. Something is evidently going on. Below is what all of my wagons are using.

Edit: My latest test using MaxAuxilaryChargingRate() is showing 5.69 below.

Edit1: I am not sure if there are custom OR brake parameters, but if there are and you are using them, try the settings below(without custom parameters) on a test consist to see if you still have the problem.

Edward K.

BrakeEquipmentType( "Handbrake, Triple_valve, Auxilary_reservoir, Emergency_brake_reservoir" )
	BrakeSystemType( "Air_single_pipe" )
	MaxBrakeForce( 15.0kN )

	MaxHandbrakeForce( 57.2kN )
	NumberOfHandbrakeLeverSteps( 100 )

	EmergencyResVolumeMultiplier ( 1.461 )
	TripleValveRatio( 2.5 )
 	MaxReleaseRate( 1.86 )
 	MaxApplicationRate( 0.84 )
 	MaxAuxilaryChargingRate( 5.69 )
 	EmergencyResCapacity( 2.604 )
 	EmergencyResChargingRate( 1.68 )
	EmergencyBrakeResMaxPressure( 90 )
 	BrakeCylinderPressureForMaxBrakeBrakeForce( 50 )

[eugenR]

edwardk, on 28 April 2017 - 11:31 AM, said:

Edit1: I am not sure if there are custom OR brake parameters, but if there are and you are using them, try the settings below(without custom parameters) on a test consist to see if you still have the problem.

Thank You for your help, but I have used the MSTS-Original Oil-Train and the original us2chemicar.wag file (from 2001) from MSTS Marias Pass for testing (look attachment). So everybody can control the behavior.

So I think there is an error in the OR code, or the Manual is not correct and this bypass-function is working only under condition's? Or am I using an OR-Brake-Option producing this faulty behavior, but I didn't found one?

Regards
EugenR

Attached File(s)

•  us2chemicar.wag (5.01K)
  Number of downloads: 224

[Csantucci]

I'm not a brake expert, but I have the impression that there's a bug. Also with Edward's parameters, after having opened the third bleed valve and having waited some time, the triple valves of the rest of the train went into emergency.

[edwardk]

I also agree there is a bug, but what is causing it? With the train I tested that had 6 cars, with the exception of the last car, I open the bleed valve on 3 of the cars and never once went into emergency. If I am correct, the bleed valve is opened and the angle cock valves are left open.

Edward K.

[ATW]

Bleed off cars makes a hole in Brake Pipe an makes leakage in BP the more you bleed an charges slowly. It happens in real life when bleeding too many cars.

[rdamurphy]

True. A train will go into Emergency if the brake pipe pressure drops too quickly. And the thing to keep in mind is that the brakes can be triggered into Emergency by a pressure drop in any car in the train. So, if the car next to the car you're isolating loses pressure, the Triple Valve dumps its pressure from the train-line directly into atmosphere, and triggers the rest of the train in sequence. If a brake parameter is way off (some are hopelessly incorrect), then it could cause the problem. BTW, the original physics on stock MSTS cars and locomotives were hopelessly inaccurate due to the mistakes made on the grades on the original Marias Pass.

Thanks,

Robert

[Csantucci]

Assuming that opening the bleed valve:
- isolates the whole brake system of the car from the brake pipe
- dumps out in the atmosphere air from brake cylinder, auxiliary and emergency reservoir
following patch should improve the situation, in the sense that the brake pipe pressure is unaffected when bleeding a car. There were in fact two points where, even with bleed valve open, brake pipe and car brake system exchanged pressures:
 AirSinglePipe_bleed1.cs.patch.zip (560bytes)
Number of downloads: 264 (source patch)


When closing the bleed valve to return to the initial state it may happen that some cars nearby have their triple valve going into emergency, due to sudden pressure drop, I assume due to the effect mentioned by Robert.
This is less likely to occur if the train has brakes released when closing the bleed valve.

Comments welcome. If this patch is considered at least an improvement, I'll upload it.

[eugenR]

Csantucci, on 30 April 2017 - 11:52 PM, said:

Assuming that opening the bleed valve:
- isolates the whole brake system of the car from the brake pipe
- dumps out in the atmosphere air from brake cylinder, auxiliary and emergency reservoir
following patch should improve the situation, in the sense that the brake pipe pressure is unaffected when bleeding a car. There were in fact two points where, even with bleed valve open, brake pipe and car brake system exchanged pressures:
AirSinglePipe_bleed1.cs.patch.zip (source patch)
Orts.Simulation.dll.zip (.dll to be replaced in x.3840)

When closing the bleed valve to return to the initial state it may happen that some cars nearby have their triple valve going into emergency, due to sudden pressure drop, I assume due to the effect mentioned by Robert.
This is less likely to occur if the train has brakes released when closing the bleed valve.

Comments welcome. If this patch is considered at least an improvement, I'll upload it.

Hi Carlo,
The bleed valve work now as written in the Manual,
Opening the bleed valve has no influence on the brake pipe and the brake system of the other cars.
Closing the bleed valve reduce a little bit the pressure in the brake pipe around the car, what is correct.
If I close the bleed valve when all brakes are applied, the brake of this car will not be applied, what also is correct, because the pressure in the AuxRes. can't go higher then the pressure in the brake pipe. In this condition the brake cylinder can't fill up. After release and apply the train brake all is o.k.

Thank You for the fix
EugenR