[Genma Saotome]

Mike B, on 02 July 2015 - 09:36 AM, said:

Please correct me, but from the way it behaves I think the BC value in OR is the locomotive (independent) brake cylinder, not the cylinders on each car.

That may be... but then why show it on every line (for each car)?

[Csantucci]

BC in the main HUD shows the pressure of the player locomotive brake cylinder.
BC in the Brake extended HUD shows the pressure of the brake cylinder of the related car.

[Genma Saotome]

Csantucci, on 02 July 2015 - 10:50 AM, said:

BC in the Brake extended HUD shows the pressure of the brake cylinder of the related car.

That is what I was referring to. The software does not appear to be doing a brake release properly... the numbers in that column change at the same rate as the column for the air reservoir making it look like they are being pumped. If that is what is going on then that is wrong. It should change to zero at whatever rate equals venting the brake cylinder into the atmosphere (which I would think is almost instantaneous). Doing so at that speed should correct whatever concerns you voiced about slow brake release.

FWIW that should have a considerable effect upon train control while descending... folks used to the old way (release and in a couple of seconds set again) may find themselves w/ inadequate air PDQ.


Is there a fixed ratio between pressure in the air reservoir and pressure in the brake cylinder? The text I've read says 2.5:1 is correct, meaning a 10 psi brake application will drop the air pressure in the car reservoirs by 10 psi and put 25psi into the brake cylinder. Is that happening?

[markus_GE]

Genma Saotome, on 02 July 2015 - 11:59 AM, said:

[...]

Is there a fixed ratio between pressure in the air reservoir and pressure in the brake cylinder? The text I've read says 2.5:1 is correct, meaning a 10 psi brake application will drop the air pressure in the car reservoirs by 10 psi and put 25psi into the brake cylinder. Is that happening?

That´s what the article by Al Krug (mentioned above) states (couldn´t find the passage now, but I recall it with 99% certainty).

Cheers, Markus

[copperpen]

I do not think the proper air or vacuum brake release rates are used, primarily because OR set out to provide a new platform for existing MSTS users. So braking characteristics need to be the same in both sims to ease the transition from old to new. Actual release rates can be set in the eng and wag files at whatever rate is deemed acceptable by the user.

MaxReleaseRate( 2.7 )
MaxApplicationRate( 1.08 )

are my current test set settings. Gives me fairly fast release rates.

[Genma Saotome]

Release rate is in the data? Good! Best way to handle it. Unit of measure is seconds, right?

I'll be changing mine ASAP.

As for the MaxApplicationRate()... that is different than what I asked about earlier but I see now the answer is in the .wag file as TripleValveRatio( 2.5 ).

[Csantucci]

Genma Saotome, on 03 July 2015 - 09:25 AM, said:

Release rate is in the data? Good! Best way to handle it. Unit of measure is seconds, right?

I'll be changing mine ASAP.

As for the MaxApplicationRate()... that is different than what I asked about earlier but I see now the answer is in the .wag file as TripleValveRatio( 2.5 ).

MaxReleaseRate and MaxApplicationRate should be in psi per seconds (accordingly to Realmuto's manual, and also accordingly to OR code), therefore release and application should be faster if values are higher.

[Genma Saotome]

Csantucci, on 03 July 2015 - 10:16 AM, said:

MaxReleaseRate and MaxApplicationRate should be in psi per seconds (accordingly to Realmuto's manual, and also accordingly to OR code), therefore release and application should be faster if values are higher.

First test values of 0.25 were, ahhh, disappointing to say the least. ;)

A value of 10 will achieve a complete release in a 50 car train in about 5 seconds. IMO that's still a bit slow so I'm going to try 15.


The testing does bring forward another question, somewhat related to brake release: The brake settings at the start an activity of mine shows the triple valve in emergency:



Given the above data as an example, is it correct for the triple valve to be in emergency? Seems to me that if the triple valve is really in emergency then isn't the brake line pressure supposed to be zero? If the brake line has air pressure then isn't the triple valve be in some other state and not in emergency? I don't know what is correct here, nor if this is data due to something in the .wag data or something about the way the game initializes things.

It stays in emergency until the air pipe pressure almost hits the value in the air reservoir (which, IIRC, is also incorrect... it's supposed to exceed that value).

So what's going on here?


Also,once the pressure equalizes the brake cylinder dumps air pretty quickly at a release rate of 10 psi/second.

[Csantucci]

The triple valve emergency issue has been solved today in release x.3186 ;)

[Genma Saotome]

Csantucci, on 03 July 2015 - 11:57 AM, said:

The triple valve emergency issue has been solved today in release x.3186 :)

Looks good.

Something else I see now... with the BrakeReleaseRate() set to do a fast release (I'm doing 15psi/sec now) I see a quick cascade down the f5 list of cars, really quick... until it gets to around 3 or 4 PSI and then it gets the slows... really slow going from 1 to zero. It makes no sense that the rate of change from n to zero should be different at any point in time. I'm also thinking 15PSI/second might be too slow but I want to ask around before I change any more values.

Any idea what causes that?