Elvas Tower: Trainbrake-Problem with Acela HHP-8 - Elvas Tower

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Trainbrake-Problem with Acela HHP-8 Rate Topic: -----

#11 User is offline   eugenR 

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Posted 20 August 2017 - 08:29 PM

View PostSerana, on 06 October 2016 - 03:57 AM, said:

I wasn't looking at the right location in the source code. I found where it's used and I think the implementation is a bit weird. I'll take a look at it after work.


Hello,
I have seen, the Problem with Standard MSTS-Engine exist again (since X3407), it is loosing all Trainbrake-Force 10s after activating the trainbrake, because in the Original-MSTS *.eng-File the Parameter DynamicBrakeHasAutoBailOff( 1 ) is set. If the Engine is used without cars, there is no possibility to stop the engine, other ways the trainbrakes of the cars are helping.

Can you please help to bring back the behavior of this engine in OpenRails from before X3407 and from MSTS?
To reset the Parameter DynamicBrakeHasAutoBailOff( 1 ) can help me, but all the user of this MSTS-Engine with OpenRails will only be annoyed and will normaly not realize what is the problem and can not complain it here!

https://bugs.launchp...or/+bug/1629635

Regards
EugenR

PS: if a code-Modification of the dynamic brake in OpenRails will be too complex, can you perhaps reset this Parameter DynamicBrakeHasAutoBailOff( 1 ) by the option "correct questionable braking parameters", then I think this function was also not working in MSTS?

#12 User is offline   Csantucci 

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Posted 21 August 2017 - 04:59 AM

The attached patch for x.3926 avoids the brake cylinder release at 0 speed and in general when DynamicBrakeForce is equal to 0 due to the DynamicBrakeForceCurves, corrects an error I found in generating the DynamicBrakeForceCurves and considers DynamicBrakesEffectAtMaximumFadeOut, which wasn't considered up to now. However I'm still not happy with the braking behaviour of the HHP8 (which by the way has in its .eng file both DynamicBrakesMaximumEffectiveSpeed and DynamicBrakesFadingSpeed at the same value, while the maximum value of the dynamic brake force should be between those two speeds).
Attached File  Orts.Simulation.dll.zip (462.29K)
Number of downloads: 251

The question is: what has been implemented, as far as I can see, is that either the air brake or the dynamic brake are active. But what if the dynamic brake force isn't enough? Shouldn't in this case both brakes be active at the same time? Or did I oversee something?

#13 User is offline   hroch 

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Posted 22 August 2017 - 04:34 AM

Hello,

Your patch correctly work only for twin pipe. For sigle pipe, when dynamic brake stops working, brake cylinder is not filled up air.
There are two systems:

1.
When the dynamic brake fades due to low or high speeds, the pneumatic brake does not replace dynamic brake (without complementary brake, I do not know how to say it correctly in technical English).
https://www.youtube....h?v=TZRTM5ZjUwY time 12:20-13:05
Attached Image: cab.JPG

gauge no.1
black needle: is pressure of pressure transducer ( changes the pressure on the voltage). In OR virtual bottle. He is always filled when the enginer use train brake controller or dynamic brake controller. Value missing in HUD and does no exist parameter in CVF file for it.
red needle: is pressure of brake cylinder.

gaude no.2
black needle: is pressure of brake pipe
red needle: is pressure of main reservoir

gaudes no.3
ammeters

Missing conditions/commands if the dynamic brake is to operate in the position of the emergency brake or not. If it works how much. The size of dynamic force is limited to avoid brake skid, because the air brake works fully. At locomotive in the video , the dynamic brake is not work in the emergency position.

2.
When the dynamic brake fades due to low or high speeds, the pneumatic brake does replace dynamic brake (complementary brake). This is according to the braking force requirement. Example: The driver has a requirement to 50kN the brake force. The locomotive performs it, the complementary brake do not work. If not, brake cylinder is filled up air. I don't know value of the pressure. I do not know the details. Every locomotive it has a different.

#14 User is offline   eugenR 

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Posted 22 August 2017 - 01:39 PM

View Posthroch, on 22 August 2017 - 04:34 AM, said:

Hello,

Your patch correctly work only for twin pipe. For sigle pipe, when dynamic brake stops working, brake cylinder is not filled up air.


Sorry, but if I modify the *.eng-File of the Acela HHP-8 to single_pipe Brake, I can't see a faulty behavior?
after switch back from dynamic to trainbrake under 5 MPS the instrument and the Window F5 Brake-Information is showing pressure in the brake cylinder.

regards
Eugen R

#15 User is offline   hroch 

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Posted 22 August 2017 - 11:56 PM

https://youtu.be/6Ua7T_GRjCM
Sigle pipe, when dynamic brake stops working, brake cylinder is not filled up air. If he applies brakes again from, the pressure in the brake cylinder doesn't increase anymore. It stays on 0 bar. This doesn´t work corretly in OR. Because the pressure in the brake cylinder grows up and then goes down. Time 0:55s.

https://youtu.be/HdoIpg07ulE
The basic HUD does not correctly display the pressure data. When the individual locomotive BC shows the pressure in the brake cylinder of the locomotive. That OK (first video). When the locomotive with wagons first BC shows the pressure in the brake cylinder of the first wagon. It's not right. It's confusing.

#16 User is offline   Csantucci 

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Posted 23 August 2017 - 12:22 AM

It seems that there is quite much to be adjusted here... I don't know if I will have skill and time for it.
Eugen and myself had some exchange of ideas, which I would like to discuss also here:
a) The maximum dynamic brake force foreseen for the HHP8 (20 kN) is very small in comparison with its airbrake force (160 kN) and also in comparison with its max continuous force (225 kN). Compare with the related value of the Dash9. Those 20 kN are probably a wrong value. So the HHP8 is probably not a good test case. We wonder if this parameter could be adjusted within the option "Correct questionable braking parameters". I think yes.
b ) In the HHP8 .eng parameters DynamicBrakesFadingSpeed and DynamicBrakesMaximumEffectiveSpeed have the same value. So there is only a point, and not a range where the Dynamic brake force has its maximum value. Thoughts like the ones of previous point can be considered.
c) In which speed range should autobailoff be active? As it is now in OR, it's active in the whole speed range. With my above patch it's active only if the dynamic brake force can be > 0 at the actual speed. However this does not seem to be satisfying, because if we are at speeds where the dynamic brake force is lower than, say, 50% of its maximum, the braking effect of the dynamic brake only would be too small. So it seems reasonable that autobailoff occurs only if at that speed the dynamic brake force is greater than a certain percentage of its maximum value. There could be a default for that parameter, that could be overridden by a new optional ORTSMinimumDynamicBrakeForceForAutoBailoff parameter.
d) What about DynamicBrakesEffectAtMaximumFadeOut? Is this value usually 0 or > 0 in real world?
e) in the HHP8 .eng file DynamicBrakesDelayTimeBeforeEngaging is set to 10. As far as I know in electric locomotives such value is practically 0. So this could also be a questionable parameter worth to be corrected.

#17 User is offline   hroch 

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Posted 23 August 2017 - 06:14 AM

a)
Yes 20 kN are a wrong value.
http://www.trainweb....ages/acela.html 3000 kW of braking power. I estimate the dynamic braking force around 150 KN. We do not know the real value of the brake force depending on the speed.
b)d)
Unfortunately I do not know. I use the parameter ORTSDynamicBrakeForceCurves to set the brake force. It's more accurate.

c)

View PostCsantucci, on 23 August 2017 - 12:22 AM, said:

With my above patch it's active only if the dynamic brake force can be > 0 at the actual speed.

https://youtu.be/6Ua7T_GRjCM
Suitable for locomotives without complementary brake, that are on my videos.
Real curve of dynamic braking force for full dynamic power. Max dynamic force is 120kN.
Attached Image: 150.2.jpg

But in OR is still a problem with the andanced model adhesion from Matej Pacha.
Attached Image: andanced model adhesion.JPG
There is a loss of power between the wheel and the rail for the real locomotive. But not as big as in OR. Loss Force is around 2-3kN and not around 40kN. Then there is little braking power on the wheel tread.

simle model of adhesion
Attached Image: simple model of adhesion.JPG
There are not losses.

View PostCsantucci, on 23 August 2017 - 12:22 AM, said:

So it seems reasonable that autobailoff occurs only if at that speed the dynamic brake force is greater than a certain percentage of its maximum value. There could be a default for that parameter, that could be overridden by a new optional ORTSMinimumDynamicBrakeForceForAutoBailoff parameter.

Suitable for locomotives with complementary brake.
For example czech locomotice 380 http://109-e.wgz.cz/...-tech-parametry
maximální výkon=maximal power
trvalý výkon=continuous power
rekuperační brzda=recuperation brake. Energy returns to wire.
odporová brzda=resintance brake. Energy is thwarted in resitor grid
Max dynamic brake is 226kN. The maximum dynamic recuperation power on the treed of wheels is 6963kW. 6963/226*3.6=110.91kmh. Corresponds to the braking characteristics.
The air brake works when the dynamic effort is low.

e)
10 seconds is a long time. Old electric locomotives have a time of about 2-3 seconds and modern diesels or old after renovation 2-3 seconds too.

#18 User is offline   Csantucci 

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Posted 23 August 2017 - 12:43 PM

hroch, many thanks for the information. I'll try to use it.

View Posthroch, on 22 August 2017 - 11:56 PM, said:

https://youtu.be/HdoIpg07ulE
The basic HUD does not correctly display the pressure data. When the individual locomotive BC shows the pressure in the brake cylinder of the locomotive. That OK (first video). When the locomotive with wagons first BC shows the pressure in the brake cylinder of the first wagon. It's not right. It's confusing.

I've looked at the code. It's intentionally done so (I don't know the reason), so I don't foresee to change it, unless there is a general agreement on that. It would be interesting if the author of that part of the code would say why he took such decision.

#19 User is offline   steamer_ctn 

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Posted 23 August 2017 - 08:46 PM

View PostCsantucci, on 23 August 2017 - 12:43 PM, said:

I've looked at the code. It's intentionally done so (I don't know the reason), so I don't foresee to change it, unless there is a general agreement on that. It would be interesting if the author of that part of the code would say why he took such decision.

I believe that the intent was to give appropriate visibility of the air brake application and release impacts on wagons and locomotives.

The Train brake controls the brake cylinder (BC) pressure along the length of the train. The purpose in showing the first and last wagon (EOT) was to show the effect of the delay as the brake application and release are propagated along the train.

The Engine brake (or Independent brake) controls only the brakes on the locomotive. Therefore it is possible to have different pressures in the engine BCs compared to the wagon BCs. So for example, if the Train brake is released, but the Engine brake is applied to 50%, then the wagon BCs would have zero pressure, but the engine BC will have 50% brake pressure.

View Posthroch, on 22 August 2017 - 11:56 PM, said:

The basic HUD does not correctly display the pressure data. When the individual locomotive BC shows the pressure in the brake cylinder of the locomotive. That OK (first video). When the locomotive with wagons first BC shows the pressure in the brake cylinder of the first wagon. It's not right. It's confusing.

In the case of a light (individual) locomotive, there is only one set of BCs, and therefore the BC pressure shown is for the locomotive (there is no other BC to display in the train brake line).

When wagons are added to the locomotive the train brake BC shown is the first wagons, as this will NOT display any pressure due to the operation of the engine brake, and therefore it is an accurate representation of the impact of the train brake on the train. If the locomotive BC was shown in this case then it could be misleading as it might appear that the train brake has applied BC pressure, when in effect it was actually applied through the operation of the Engine brake.

The ideal outcome should be to only show Train Brake impacts in the Train Brake line of the HUD and Engine Brake impacts in the Engine Brake line.

#20 User is offline   eugenR 

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Posted 24 August 2017 - 12:33 AM

View PostCsantucci, on 23 August 2017 - 12:22 AM, said:

It seems that there is quite much to be adjusted here... I don't know if I will have skill and time for it.
Eugen and myself had some exchange of ideas, which I would like to discuss also here:
a) The maximum dynamic brake force foreseen for the HHP8 (20 kN) is very small in comparison with its airbrake force (160 kN) and also in comparison with its max continuous force (225 kN). Compare with the related value of the Dash9. Those 20 kN are probably a wrong value. So the HHP8 is probably not a good test case. We wonder if this parameter could be adjusted within the option "Correct questionable braking parameters". I think yes.


Hi Carlo,
I have read on a page of a Swiss engine driver, that the brakeforce of the dynamic brake would be approximately the same as the traktionforce of the engine, because it usually produced by the same machines. So I think we should the dynamic brake not only compare with the trainbrake force but also with the maxforce of the engine.

regards
EugenR

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