Air Brake Problem

Hi Guys, i would appreciate any help that i can get.The problem i have came about after i adjusted the brake valve and then the compressor settings to get much more realistic recharge rates. When i adjusted the recharge rates i discovered that the train pipe is charged through the locomotives Main Reservoir. The pressure in the Main Reservoir drops to zero and builds up to the train pipe pressure every few seconds then drops again until the train pipe is fully recharged.This in itself is not a problem until i tried to hold a train on a hill with just the independent brake while i recharged the train pipe.(as happens in real life)The independent Brake gets its air from the Main Reservoir and if the reservoir is low or near zero then their is not braking effort. (the locomotives ive worked on had seperate brake reservoirs)I have been unable to get the main reservoir to not drop while recharging or get the independent brakes to work without using air from the Main Reservoir.my questions are has anyone else noticed this anomoly?Has anyone got a system other than air to work correctly as locomotive independent brakes?Is there a locomotive out there somewhere that has realistic recharge rates. ( i did some calculations while travelling on a freight train, it doesnt have to be completely accurate, but more realistic would be nice, atleast 3 minutes for a minimum reduction recharge on a 50 wagon train)Thanks for any help whatsoever.Nick.

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RE: Air Brake Problem, kevarc, Jun-03-03, 10:10 AM, (1) RE: Air Brake Problem, N_A_J, Jun-03-03, 11:18 AM, (2) RE: Air Brake Problem, plainsman, Jun-03-03, 11:29 AM, (3) RE: Air Brake Problem, N_A_J, Jun-03-03, 11:40 AM, (4) RE: Air Brake Problem, plainsman, Jun-03-03, 11:47 AM, (5) RE: Air Brake Problem, xlspecial261, Jun-03-03, 07:34 PM, (6) RE: Air Brake Problem, N_A_J, Jun-03-03, 11:27 PM, (7) RE: Air Brake Problem, plainsman, Jun-04-03, 01:10 AM, (8)

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Brake_Train ( 0 1 0.0125 0.75
NumNotches ( 5
Notch( 0 0 TrainBrakesControllerReleaseStart )
Notch( 0.3 1 TrainBrakesControllerGraduatedSelfLapLimitedHoldingStart )
Notch( 0.85 0 TrainBrakesControllerSuppressionStart )
Notch( 0.9 0 TrainBrakesControllerContinuousServiceStart )
Notch( 0.95 0 TrainBrakesControllerEmergencyStart Make sure the Notch ( 0.3 has the holding between limited & Start.Kevin Arceneaux
DEFAULT IS FOR DUMMIES
Lone Wolf Activities Forum on www.3DTrains.com

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Thanks for that kevarc, but it does not seem to have made any difference, an easy way to see what i mean is with a long train, put the independent brake on full, place the train brake into emergency, when the train pipe is at zero, release the train brake, u will see the needle of the brake cylinder pressure drop. This is not meant to happen.Nick

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Hello Nick,
What locomotive are you currently using?
Bob

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Hey Bob, this problem is one that has happened with any diesel electric, Air braked locmotives, im sure other people have changed locomotives to have realistic recharge times.It is possibly a major fault that cannot be altered due to limitations of msts. Im just trying to work around it.Nick.

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LAST EDITED ON Jun-03-03 AT 11:52 AM (EDT)

First,
modify this area as shown.
AirBrakesAirCompressorPowerRating( 2.68 )
AirBrakesMainMinResAirPressure( 14.7 )
AirBrakesMainMaxAirPressure( 140 )
AirBrakesMainResVolume( 8.6 )
AirBrakesAirCompressorWattage( 19000 )
AirBrakesCompressorRestartPressure( 132 )
AirBrakesAirUsedPerPoundsOfBrakePipePressure( 1.46 )
AirBrakesHasLowPressureTest( 1 )
AirBrakesIsCompressorElectricOrMechanical( 0 )Then near the top of the file:
MaxBrakeForce( 91kN ) EmergencyBrakeResMaxPressure( 110 )
TripleValveRatio( 2.5 )
MaxReleaseRate( 6 )
MaxApplicationRate( 4.5 )
MaxAuxilaryChargingRate( 1.8 )
EmergencyResCapacity( 10 )
EmergencyResChargingRate( 1.9 )
BrakeCylinderPressureForMaxBrakeBrakeForce( 64 )
Let me know where you want it to go from there?
Depending on the locomotive you are using, you may want to drop the compressor wattage to about 13500.
Bob

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A problem the sim has is that the trainline takes air faster than the compressor can pump air. This is not realistic for the most part.When you cut the air into a "dry" train (One with no air, bled off, etc) your main res pressure will drop but not down to the same level as the trainline. The compressor will generally kick in at 120 PSI, and while your pressure will likey still drop, it won't go to 50 PSI. If you drop below 100PSI on the main res, you rev up the prime mover, usually to run 4, to speed up the compressor raising it's charging rate. (On newer GE's you only put it in run 1 as they have electric compressors. Newer EMD's automatically do this if main res pressure drops to 100.)On North American locomotives your independant is supplied from the main reservoirs. If the pressure in them is only 50 PSI, thats all you get for your indy.Todd

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Thankyou very much to Todd and Bob, i seem to have found a reasonable comprimise.Todd's analysis of the sims problem is as i also suspected. This is sadly another fault in the sim that would be nice to have improved before the next version of the sim.I have witnessed how it actually happens in real life on a freight train when as an observer we nearly ran out of air on a long down hill stretch, the train came to a hault, but we applied the loco brakes to hold it on the hill while we recharged the train brake, the locomotive brakes could not hold us but stopped the acceleration of the train enough for us to get enuff air back to make another application.If life was like msts, what could be more scarey than having to make an emergency application on a long down hill, as soon as u released the brake u would not be able to make a train brake application and you would not have any independent brakes.Out of interest, is there a locomotive out there that has realistic recharge times, my experience is limited to 50 car trains, id be interested to know how long it takes to recharge a 100 or more car train.Thanks.Nick

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Hi Nick,
I might suggest you get the Class 80 #8048 from the library, and then get the version 4.5 (V4.5) physics update for it, also in the library. It will slip right in the file, and give almost the same performance as the numbers above. You could tweak that file with the above numbers to get the same performance if needed. cl80v45.zip is the physics update file name. 8048.zip is the locomotive file, by Gavin Mclaughlan.
For US roads, try bn5569.zip, a model of the BN rebuilds of GE C30-7 units. File crgp35.zip also contains locomotives with my .eng files already installed. For Payware, many of the recent 3D Trains and DekoSoft units have my physics. Try the new AS-16 and AS-616 Baldwin units, they will also have the same properties.
Hope this helps,
Bob

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