Compressors

I know that how often a compressor goes off depends on the set pressure and braking systems, but is it possible to have more than one compressor on a multiple unit going on and off simultaneously? Or is this once again another dreaded limit of the bve code?

Hi,

Why would you need multiple compressors coming and going off at different times?

On a multiple unit or more than two multiple units coupled together there should only ever be one brake and main res pipe for the whole train, otherwise your in the dirt or worse. The train is now under the control of one brake stand no matter how many units are coupled together. Other forms of braking ie regenerative and ep (electro pneumatic) may be the systems used in normal operation but should you need to stop in an emergency or the previously mentioned braking systems fail the driver still can reduce the brake pipe pressure bringing the train to a stand.

So the air pressures in the train may vary slightly over the length of the train but when the pressure drops through the use of the brake or door operation (if they're air operated and not electric) the main res pressure regulator will turn all the compressors on at once and they'll run until the maximum pressure is reached and then switch off.

Safety interlocking should prevent the brake pipe being controlled (reduced or recharged) from more than one brake stand, otherwise your in for a runaway scenario (good material for action movies but deadly in real life).

If there are any LU operators in the Forum they would be able to give the gen on how their sets operate. Multiple units may have more than one compressor but are controlled / regulated as one as part of a closed system.

Bye for now,

Stephen.

Eh? I didn't say coming off and going on at different times. I said going on and off simultaneously which means at the same time.

the main res pressure regulator will turn all the compressors on at once
and they'll run until the maximum pressure is reached and then switch
off.

Yes but the problem i'm having is that I only get one compressor coming on and going off and not 4. The question is how can I give my train 4 compressors as in one under 4 carriages. Or is this a limit of bve as the exterior views are only coded to have one compressor?

I ask this because for some reason depending on what the brakes are set to in the train editor, I can have one compressor going off in car 2, one in 4, and one in car 7, but yet never at the same time which it should be. This also seems to occur when I don't have the correct brake setting; otherwise with the correct brake setting I only have one compressor going on and off.

Well, the ICE 3 has a tremenduous use of air. External doors, internal doors, WCs, WC doors, suspension, sand dryer... Thus there are two compressors with two different activation threshold pressures. I'll look it up, I don't know it by heart for sure, should be 8.5 and 8.0 bar.

Yes but how would you code 2 compressors in bve?

Sorry, that was an answer to Stepen's post. I don't have an idea for you, sorry.

I am starting to think that in spite of the fact that openbve has exterior views, the sounds are still first and foremost aimed at the cab perspective. But if that is indeed so, i'm still confused as to why i'm getting different compressors on different carriages going off when they feel like it, and not at the same time.

Not 100% sure, but the answer should be is in the NumberOfMotorCars parameter in the #CAR section of Train.dat file.

Some of this data define what are the cars emitting noises in the external view.

#CAR
30 ; MotorCarMass
2 ; NumberOfMotorCars
10 ; TrailerCarMass
7 ; NumberOfTrailerCars
24.8 ; LengthOfACar
1 ; FrontCarIsAMotorCar
2.6 ; WidthOfACar
3.2 ; HeightOfACar
1.5 ; CenterOfGravityHeight
5 ; ExposedFrontalArea
1.6 ; UnexposedFrontalArea

To notice that in case of modern EMU trains, in which more motor cars can be mixed with one or more trailer cars, these informations are not enough to establish the exact position of each "noisy" car inside the convoy.

Especially as modern MU have distributed traction. While e.g. the ICE 1 still technically is a locomotive, 12 carriages and a locomotive again when it comes to where what is, the ICE T 411 e.g. consists of transformator carriage (pantograph, transformator, compressor), converter carriage (power converters, engines), engine carriage (engines), middle carriage (batteries), engine carriage, converter carriage, transformator carriage. So each carriage has its own different sound.

Hi Ad1992,

I do apologise, I woke up in the middle of the night and posted, hmm not a good idea.

Bye for now,

Stephen.

That's alright, Stephen - it would be the middle of the day here.............!


cheers,

John

So I was right, it can't be done due to bve's basic source code.