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Therock
August 2nd, 2016, 07:47 PM
Here's a question, or I suppose two- why is it that bailing off in Trainz has never worked as intended?

In the real world when you set air on the automatic brake valve that applies the brakes on the locomotives as well as the entire consist. In an effort to prevent slack run-in a good engineer would actuate the independent brake valve so that the locomotive's brakes remain released while the rest of the train sets up with whatever reduction was made to the equalizing reservoir. After this actuation occurs the brakes on the locomotive stay [B]released until more air is set on the automatic valve, in which case, again, in an effort to keep the slack stretched a good engineer would bail off.

So why is it that in literally every single version of trainz when the train brakes are applied, and you press z or whatever you have set to actuate your independent valve, it kicks off the engine brakes yay great good job... then about 4 seconds later they start coming back on? You have to keep mashing the bail off key every so often to make sure your train doesn't run into you which isn't how the whole system works at all. This is something that has never worked correctly and I'm wondering why it's never been fixed or even addressed properly.

Can we ever expect to see a correct bail-off feature in Trainz?

EverTrainz
August 2nd, 2016, 09:30 PM
Can we ever expect to see vacuum brakes in Trainz?

S301
August 6th, 2016, 12:46 AM
Here's a question, or I suppose two- why is it that bailing off in Trainz has never worked as intended?

In the real world when you set air on the automatic brake valve that applies the brakes on the locomotives as well as the entire consist. In an effort to prevent slack run-in a good engineer would actuate the independent brake valve so that the locomotive's brakes remain released while the rest of the train sets up with whatever reduction was made to the equalizing reservoir. After this actuation occurs the brakes on the locomotive stay [B]released until more air is set on the automatic valve, in which case, again, in an effort to keep the slack stretched a good engineer would bail off.

So why is it that in literally every single version of trainz when the train brakes are applied, and you press z or whatever you have set to actuate your independent valve, it kicks off the engine brakes yay great good job... then about 4 seconds later they start coming back on? You have to keep mashing the bail off key every so often to make sure your train doesn't run into you which isn't how the whole system works at all. This is something that has never worked correctly and I'm wondering why it's never been fixed or even addressed properly.

Can we ever expect to see a correct bail-off feature in Trainz?

Would this not depend on the type of locomotive in use? On many locos, when you push down on the independent brake (or pull on the bail off valve), it is sprung to close when you release it. Would the triple valve not then push air back into the brake cylinders in this situation? I don't currently have access to any westinghouse books that might cover this subject, so am not sure off hand, however this is the impression I get on how it works.

Regards
Zec

Therock
August 6th, 2016, 03:31 PM
Would this not depend on the type of locomotive in use? On many locos, when you push down on the independent brake (or pull on the bail off valve), it is sprung to close when you release it. Would the triple valve not then push air back into the brake cylinders in this situation? I don't currently have access to any westinghouse books that might cover this subject, so am not sure off hand, however this is the impression I get on how it works.

Regards
Zec
I'm talking in particular about 26L brake equipment, though many if not all other Westinghouse setups similar to the 26L operate in a similar manner with regards to bailing off. I too don't have access to books that say either way but the book I do have regarding 26L equipment [which it would be fair to say most North American locomotives as well as many exports at the least are equipped with] states nothing beyond "To make an independent release of an automatic brake application, depress the independent brake valve handle." I've never heard of a prototype instance with Westinghouse equipment where after bailing off, the independent brakes actually set up again on their own. Any time I operate the brakes on our Alco which has a 26C stand bailing off keeps the brakes off on the engine until more air is applied to the train brakes. I'm certain if you asked anyone else who operates the real thing they would say the same.

Also locomotives don't have triple valves.

TRam__
August 6th, 2016, 05:00 PM
That depends for settings of enginespec, especially on the ratio between axilliary reservoir and brake cylinder volumes, and their flows. For example make a test with <kuid2:400260:7677218:7> , i can't get re-applying of brakes after bailing off with it (note: delete-and-place locos and wagons after changing of their enginespecs)

Kiwi_Rail
August 6th, 2016, 05:19 PM
First of all let me just state that all of my training/experience is with the 26L system - I cannot guarantee that this is the same for other systems but I would say the bail-off characteristics are the same throughout all westinghouse gear of the past century. I can also say that over here a locomotive that re-applys the brakes after a bail-off would fail a brake test and be banned from running as part of a train until the issue is fixed.


On many locos, when you push down on the independent brake (or pull on the bail off valve), it is sprung to close when you release it. Would the triple valve not then push air back into the brake cylinders in this situation?

You are assuming that the depression is venting the brake cylinders themselves? It is actually venting the control pressure being fed to the J1 valve - the brakes are then released just as they are when the train brake is released.

The important thing to understand about the 26L system is that it is all a series of signal pressures, controlled by diaphragms in each valve. If you make a reduction on the train brake (26D) it first drops the equalizing reservoir which the brake pipe then equalizes with. At this point the 26F detects the pressure change, and sends a signal pressure through a double check valve to the J1 valve, which then sends air from the main res to the brake cylinders.

Brake application>EQ drops>BP equalizes with EQ>26F signals J1>J1 applies brakes

How the bail-off works is it vents the control signal between the double check valve and the J1 - As far as the 26F is concerned it still thinks the brakes are applied but the J1 thinks they are released. As Ryan says, If you make a further reduction the brakes come back on, this is because the 26F has changed the signal pressure and pushed through that double check valve again - thus requiring a further bail-off.

This issue has bugged me for years - Constantly mashing the D key whenever bailed is a pain in the ass when you have other stuff to concentrate on. Why is it like this when it seems to me having it be once and off would be simpler to program than the current setup?

And yea locomotives in my experience don't have triple valves.

-Will

Therock
August 8th, 2016, 02:40 PM
That depends for settings of enginespec, especially on the ratio between axilliary reservoir and brake cylinder volumes, and their flows. For example make a test with <kuid2:400260:7677218:7> , i can't get re-applying of brakes after bailing off with it (note: delete-and-place locos and wagons after changing of their enginespecs)
Very interesting. I applied your engine spec to one of my GP38-2 models and was able to get the locomotive brakes to stay off after bailing, then set up again with more air on the train brakes- this worked actually a couple of times for each additional application and I think we've got a winner here. Thanks for the assistance TRam, this is something I foresee hopefully becoming a new standard in the very near future.

ZecMurphy
August 9th, 2016, 08:41 PM
Thanks guys, definitely learned a bit here! :) (and apologies for username change, just happen to be logged in through this one lol ).

My experience is around #4 and A6ET brakes, even then is fairly limited experience, so wasn't sure. I'm fairly sure that the earlier brake systems will automatically re-apply after using the bail off, but will have to await confirmation from a mate who drives the big ones (steam, diesel and electric, including current mainline stuff) here in Aus :)