[darwins]

Quote

Each Motorcoach was provided with an air compressor, these being electrically linked so all operated together in a train.

https://www.bloodand...motorunits.html


Is there a way to make this work in OR?


I have a four car electric multiple unit = Motor + Trailer + Trailer + Motor. The brake system in use is:

BrakeSystemType( Air_twin_pipe )
ORTSMainResPipeAuxResCharging(false)

At present the compressors are *not* electrically linked. They are behaving as if each individual compressor is operated by its own pressure switch.

Since the main reservoir pipe pressure always drops at the front of the train slightly before it drops at the rear of the train, only the front compressor works, the rear compressor never gets switched on. As a result the charging time is longer than it should be and would get longer as more units are added.

[Weter]

I doubt, that's because absence of electric linkage.
We have compressorRestartPressure() parameter, so what You've described, looks like a bug for me.

[Marci]

darwins, on 24 October 2022 - 02:54 AM, said:

https://www.bloodand...motorunits.html


Is there a way to make this work in OR?


I have a four car electric multiple unit = Motor + Trailer + Trailer + Motor. The brake system in use is:

BrakeSystemType( Air_twin_pipe )
ORTSMainResPipeAuxResCharging(false)

At present the compressors are *not* electrically linked. They are behaving as if each individual compressor is operated by its own pressure switch.

Since the main reservoir pipe pressure always drops at the front of the train slightly before it drops at the rear of the train, only the front compressor works, the rear compressor never gets switched on. As a result the charging time is longer than it should be and would get longer as more units are added.

Hi.
In the case of vehicles operating in synchronous operation, the task of the remote control cable(s) is to ensure the connection between the same locomotives, or motor cars, or control cars. Unfortunately, the remote control cable does not fit very well with the OR. For example, if the remote control cables of two electric locomotives are separated, the locomotive disconnected from the remote control will also release its pantograph.

Sincerely,
Marci

[cesarbl]

Should this be available by default for all MU'ed locomotives, or with an engine parameter?

[Weter]

Here, most often the only common MU's system is pneumatic.
Units, equipped with compressors are autonomous and equal, because it's impossible to predict, how many of them would be coupled into common train, which of them may fail... So each has it's own pressure sensor-relay, activating adjacent compressor, if pressure in MR (either coupled by hoses or no) drops less, than defined.

[darwins]

cesarbl, on 24 October 2022 - 08:49 AM, said:

Should this be available by default for all MU'ed locomotives, or with an engine parameter?

In real life there are two different possibilities, as Marci indicated above. So if the existing one is kept by default, then perhaps another option is needed for those that really are fully MU'ed.



1. Compressors not synchronised (usually where there is no MU connection):

Steam Locomotives (also if assisted by Diesel or Electric locomotives).
Diesel or Electric locomotives that are at different locations in the train if not MU linked.
Any locomotives without MU link that use Air_Single_Pipe.
Some multiple units as described by Weter.


The present OR parameter works correctly for these cases.


2. Compressors synchronised

Most diesel multiple units
Most electric multiple units

It may be best to make a new parameter for these, as Weter has highlighted an exception and OR does not know the difference between a multiple unit train and a locomotive hauled train.


3. Not sure / don't know

Diesel and Electric locomotives if working in multiple - as in double heading in Europe.
Diesel and Electric locomotives working in multiple in different parts of a train - as in freight trains in USA.

[Coolhand101]

In older OR versions, if the brake type was "Air Twin Pipe" or "EP", both the compressors on EMUs with two compressors worked in sync. If the brake type was "Air single pipe", only the front compressor worked as Darwin described!

Thanks

[cesarbl]

Probably it was broken when I introduced the air propagation code to the main reservoir pipe. Previously pressure was instantly propagated and was the same for every locomotive, so the compressor start condition was fulfilled for all locos.

I'll add the parameter ORTSCompressorIsMUControlled(1).

[Marci]

darwins, on 24 October 2022 - 10:52 AM, said:

3. Not sure / don't know

Diesel and Electric locomotives if working in multiple - as in double heading in Europe.
Diesel and Electric locomotives working in multiple in different parts of a train - as in freight trains in USA.

Hi.
From a European point of view, the following can be said: In general, the same locomotive works together with the same auxiliary machine, provided that the locomotives allow synchronous control. (For example, in the case of the MÁV V63 series, synchronous operation was possible in the range of track numbers 001-012 (which no longer works), in the range of track numbers 013-056 this was no longer established at the factory. It can be done if the remote control allows it, (passenger train operation case) that there is a locomotive at each end of the train, which operate in sync. In the case of freight trains, the situation is that if the locomotive is at the end of the train, it can be a permanent but also a temporary helper. The temporary helper is not connected to the train, it only helps in starting/ until the train reaches the maximum allowed speed. The brake of the permanent helper is connected to the braking system and has its own personnel.

Sincerely,
Marci

[cesarbl]

I added the parameter ORTSCompressorIsMUControlled (for the engine() section of the .eng file) that synchronizes compressor startup.