[disc]

I've just committed a fix, that makes bailoff possible on twin pipe brake systems. Currently the independent brake cylinder pressure drops as the player hold the bailoff button, and stays like that.
However some say that the european brakes with triple valve and graduated release, recharge the brake cylinder if the bailoff control is released, that's why bailoff can be locked in reality (like the sander).
How this works on other airbrake systems?

Also i'm thinking about to change the graduated release setting. Currently the graduated release setting is global at the options, but i think a new eng/wag parameter that would decide IF present, otherwise the global option would be used.

[gpz]

 disc, on 01 December 2015 - 03:23 AM, said:

Also i'm thinking about to change the graduated release setting. Currently the graduated release setting is global at the options, but i think a new eng/wag parameter that would decide IF present, otherwise the global option would be used.

That's a good idea! MSTS didn't have usable parameters for indicating ability of graduated release. Just please note, that global option actually influences two different things: (1) the engine brake valve, that controls the brake pipe pressure, or (2) the wagon brake system, that acts based on the received brake pipe pressure signal. Both of these systems can either be releasable gradually or not. Don't forget about modifying both ends.

[Howky]

From czech locomotive
emptying
Most of the locomotives is equipped emptying, which is usually the type DAKO OL2 (emptying Depot). This device is controlled simply by pressing and serve to release pressure air from the locomotive brake cylinders, while the rig remains braked behind the locomotive.

[disc]

 gpz, on 01 December 2015 - 07:33 AM, said:

That's a good idea! MSTS didn't have usable parameters for indicating ability of graduated release. Just please note, that global option actually influences two different things: (1) the engine brake valve, that controls the brake pipe pressure, or (2) the wagon brake system, that acts based on the received brake pipe pressure signal. Both of these systems can either be releasable gradually or not. Don't forget about modifying both ends.

if i disable graduated release, the engine brake still have graduated release. Also i saw in railworks that engine/independent brake release is always gradual, only the trainbrake isn't.

in .eng the most of the non default locomotives and some wagons have "Graduated_release_triple_valve" in brakeequipment block, and some default rolling stock have "distributor" string there, which would mean the same, and used by some parts of brake code, but mostly it's overridden by the global setting. Perhaps these should be used.

[Coolhand101]

 disc, on 01 December 2015 - 03:23 AM, said:

Also i'm thinking about to change the graduated release setting. Currently the graduated release setting is global at the options, but i think a new eng/wag parameter that would decide IF present, otherwise the global option would be used.

I was thinking about a parameter in eng/wag to decide what setting. A welcome feature!


For realism, is it possible to look at the independent engine brake, to take the pressure directly from the main reservoir?

In the UK, the engine brake is called the "straight air brake", getting the pressure directly from the main reservoir.

Currently in OR, the engine brake will show pressure, even if the main res is empty.

Another welcome feature will be the engine air brake working with a vacuum train brake.

The dynamic brake still works under vacuum( my engine brake for now), providing the reverser is in forward or reverse.



Thanks

[gpz]

 disc, on 01 December 2015 - 08:37 AM, said:

if i disable graduated release, the engine brake still have graduated release. Also i saw in railworks that engine/independent brake release is always gradual, only the trainbrake isn't.

I'm sorry, I think I used the wrong wording. When I wrote "engine brake valve" I actually meant "the engine's main brake valve". So I was not speaking about the engine-brake, but about the main brake valve in the engine. But maybe we can assume that if the engine is equipped with "distributor" type triple-valve, then also its main brake valve is capable of controlling the brake release procedure gradually.

[disc]

I'm trying to implement main reservoir pressure loss on applying engine brake. Do anyone know how can i compute how much air is consumed from MSR at each 1 psi application of engine brake?
Currently i'm using MSR pressure MINUS engine brake pressure change DIVIDED by MSR volume. But still a brake cylinder volume is need... or something else. Do anyone know the volume of a trainbrake cylinder?

[steamer_ctn]

 disc, on 05 December 2015 - 12:28 PM, said:

Do anyone know the volume of a trainbrake cylinder?

The volume of the brake cylinder will be dependent upon the size of the cylinder and the amount of piston travel.

For a rough guide refer to the table on this page which has some typical cylinder sizes and volumes.

There are some brake manuals in the reference section which may have further information.

[gpz]

Disc, don't try to guess the brake cylinder volume, it is available from the eng parameters, however it is tricky to get that, since it is indirect.

There is the "emergencyrescapacity" MSTS eng parameter. You have to divide it by the "emergencyresvolumemultiplier" to get the aux.cyl volume. If you further divide it by the "triplevalveratio", you get the brake cylinder volume. These MSTS parameters are all parsed for in AirSinglePipe.cs, the corresponding variables containing them are EmergResVolumeM3, EmergAuxVolumeRatio and AuxCylVolumeRatio, respectively.

So you don't need to implement any new default values for these, just use them. The only thing you might need to consider is adjusting the EmergResVolumeM3 default value, since that is set in eng files only rarely, so most of the eng-s are using the default we set.

[disc]

 gpz, on 06 December 2015 - 04:48 AM, said:

There is the "emergencyrescapacity" MSTS eng parameter.

I saw that, but on twin pipe configurations, the "ergbrk" column in brake information was empty. However in debug mode is see that EmergencyResvolumem3 is always set.

But still using emergencyrescapacity as starting point, max brake force isn't considered, while the brake cylinder diameter (so as the volume) depends on the max force, because the pressure is fixed.