Elvas Tower: Vacuum Brakes, angle cocks and hoses. - Elvas Tower

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Vacuum Brakes, angle cocks and hoses. Brake timing issue Rate Topic: -----

#1 User is offline   Paul B 

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Posted 26 January 2022 - 10:04 AM

Hello;

I have recently been working on a series of mods implementing vacuum brakes on some locos and rolling stock and in the process of testing have come across an issue relating to angle cocks (& brake pipe connections)...

The angle cocks work correctly in respect of shutting off/isolating the train pipe from one part to another and at the ends of the train.

However when the angle cocks are used to close off part or all of the train from the locomotive, there is no difference in the time taken to create/destroy the vacuum. The timings still behave as if everything was connected up and no angle cocks were closed.

For example if the angle cock on the rear of the locomotive coupled to a long train is closed the vacuum should rise and fall at the same rate as with a light engine (since with the rear angle cock closed you are only creating/destroying vacuum on the loco not the whole train) However at present the vacuum rises and falls (slowly) as if the whole train was still connected.

Disconnecting the pipes makes no difference, even with angle cocks shut and the pipes disconnected the brakes still apply and release slowly as if everything was still connected up. You have to physically uncouple the cars from the locomotive before any change is observed.

It seems like the position of the angle cocks and the connection of the brake pipes is not being considered when OR calculates the application and release times – I guess this is based on brake pipe volume. It seems like it is just using the whole volume of all the cars/wagons coupled and not considering that some of that volume may be isolated due to closed angle cocks and/or disconnected brake pipes? Should we see a change in brake pipe volume in the HUD when angle cocks are closed or pipes connected/disconnected?

The issue occurs with both straight and automatic vacuum brakes. Air brakes do not appear to be affected as far as I can tell.

Hope this makes sense, sorry for the long explanation.

Regards;

-Paul Burton

#2 User is offline   darwins 

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Posted 26 January 2022 - 11:15 PM

Thanks for a detailed explanation. Hopefully that will help to resolve the problem.

The same is not observed for air brakes because, as far as I know, system air volume has not yet been factored into air brake operation.

Whilst I can not fix the bug, I am going to take the opportunity to repeat an old request of mine:

"Please can the angle cocks be removed (or hidden) from the vacuum brake system." (Or at least when the hoses are coupled.)

With vacuum brakes there are no angle cocks. Hence when the pipes are connected there is no way to block the connection from one car to another.

When the pipes are disconnected there are then two options:

The pipe (or bag) is not on the dummy coupling = angle cock is open - this is always the case immediately when you disconnect any pipe.

The pipe (or bag) is on the dummy coupling = angle cock is closed - you can not put the bag on the dummy until after you have disconnected it.

#3 User is online   rickloader 

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Posted 27 January 2022 - 05:10 AM

Hi Paul! It is good to know you are working on Vacuum brakes.
I agrre with Darwin that angle cocks are a distraction on vacuum systems. It is a neat idea to substitute "pipe - on - dummy" for angle cock closed.
However, I question whether OR should include duties beyond the drivers responsibilities. Or I suggest these extra duties should be optional.
In British practice the driver would not deal with hoses. That would be the shunters job, or the fireman /2nd man. The In game reality in having too many chores is that train shunting operations could not always be completed in the time available in the timetable.
If players want extra duties - navigate to the car, manually couple, connect pipes, release handbrakes, blow up brakes, then fine. But there should also be an auto couple option too.
Rick

#4 User is offline   Paul B 

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Posted 27 January 2022 - 08:09 AM

Hello;

Darwin and Rick, you are both correct regarding the stopper/dummy in British practice. Some straight vacuum brake systems employed angle cocks I believe. But we still need a mechanism for closing off the train pipe between vehicles and at the ends of the train...

In practice the driver may ask for the brake pipes to not be connected. During complex shunting of vacuum braked vehicle the shunter or whoever would not want to wrestle with the pipes every time a vehicles was coupled or uncoupled. The pipes would be left in whatever state they are, the strings pulled (reservoirs emptied) and the stock would be treated as unbaked. All the braking would be carried out with the loco brake be it steam, vacuum, air or whatever.

I personally think there is need for a means of closing off the train pipe, which we have at the moment and which works in every respect except for the issue described in the original post.

Cheers;

-Paul

#5 User is offline   Paul B 

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Posted 28 January 2022 - 04:37 AM

View Postrickloader, on 27 January 2022 - 05:10 AM, said:

If players want extra duties - navigate to the car, manually couple, connect pipes, release handbrakes, blow up brakes, then fine. But there should also be an auto couple option too.


Without taking this off topic from the original bug report - we kind of already have some automation with the two key commends by default:

'#' -- (Auto Connect hoses and auto angle cocks)
'Shift+/' -- (Initialize brakes - charges the system releases handbrakes etc.)

Regards;

-Paul

#6 User is offline   cjakeman 

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Posted 28 January 2022 - 11:42 AM

Hi Paul,


View PostPaul B, on 26 January 2022 - 10:04 AM, said:

The angle cocks work correctly in respect of shutting off/isolating the train pipe from one part to another and at the ends of the train.

However when the angle cocks are used to close off part or all of the train from the locomotive, there is no difference in the time taken to create/destroy the vacuum. The timings still behave as if everything was connected up and no angle cocks were closed.

There seems to be a lot of interest in this. I would say it's an extension or a new feature rather than a bug.

It would be a shame if this thread just faded away as new topics come along, so would you add a new Trello card (or, if you prefer, a new Blueprint) with a link back to this thread. That way, when a developer becomes free, he can pick up the details.

#7 User is offline   Paul B 

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Posted 29 January 2022 - 03:07 AM

Hi Chris;

Trello card #523 raised with a link to this thread.

Thanks;

-Paul

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