OR brake values for Class 158 DMU

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OR brake values for Class 158 DMU

Post  Shawmut on Fri 18 Aug 2017, 10:01 pm

Gentlemen,

When I created the "Photons66" midi-route (see thread here) to test Ged's latest version of his DiY Mini-Routes utility, I also downloaded 1 engine file per each of the 5 routes I installed to run explore activities. For the Henley Branch I chose a nice Anton Courtney-May repaint of class 158 in FGW livery.

The model installed beautifully and ran just as well in MSTS, but in ORTS it wouldn't budge. You could throttle up to 100% and it would smoke like crazy, but wouldn't move. Past experience with this problem points to the brake values in the engine file, and that ORTS values are NOT the same as the default MSTS ones.

So I created an OpenRails include file (see the latest ORTS manual, page 116) for the three engine files that come with this Class 158, and used the following values to override the MSTS values when operating in ORTS:

BrakeEquipmentType ( "Triple_valve, Auxilary_reservoir, Emergency_brake_reservoir" )
BrakeSystemType ( Air_single_pipe )
MaxBrakeForce ( 179.1kN )
TripleValveRatio ( 2.5 )
MaxReleaseRate ( 40 )
MaxApplicationRate ( 40 )
MaxAuxilaryChargingRate ( 35 )
EmergencyResCapacity ( 10 )
EmergencyResChargingRate ( 30 )
EmergencyBrakeResMaxPressure ( 110 )
EmergencyResVolumeMultiplier ( 1.461 )
BrakeCylinderPressureForMaxBrakeBrakeForce ( 70 )

Now, these values do work in ORTS, and once I had created these files the consist, which consisted of a DMSA, a DMSB and a DMSC (the latter 2 reversed), moved right out. So I should be happy, right?

Well, the only values I could find for diesel brakes compatible with ORTS were for large, North American diesel locomotives - overkill for a DMU. So would any of you experienced with ORTS phyics care to critique the above values? To begin with, I'm assuming that the MaxBrakeForce value is way out of line, but again I have no idea what a good value would be.

Any thoughts would be greatly appreciated.

Kind regards,

David

Shawmut

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Age : 68
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Re: OR brake values for Class 158 DMU

Post  StephenRWells on Sat 19 Aug 2017, 12:33 pm

Hi David,

The problem is simple, Open Rails cannot accept a combination of air and vacuum brakes in the eng. file. If you change to all AIR brakes in the complete consist then the train becomes driveable.

Regards,

Stephen
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StephenRWells

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Re: OR brake values for Class 158 DMU

Post  Shawmut on Sat 19 Aug 2017, 5:15 pm

Hi Stephen,

Thank you for your quick response. I created 3 OpenRails "include" engine files using the heavy diesel air brake values I listed in my OP, and they did indeed work. Further, I could find no evidence that the 158's ever used vacuum brakes, which the original .eng files come equipped with.

So I began experimenting and doing research on braking systems ("Basic research is what I'm doing when I don't know what I'm doing." - Werner von Braun). I remembered that my Making Tracks Class 150 in RR livery worked just fine in OR, so I hauled out its .eng file and looked at the brakes in both the Wagon and Engine areas. Lo and behold they were listed as "EP" brakes.

Hmm, never heard of EP brakes, time for some of that research. This article, from a really useful website I immediately bookmarked, gave me an introduction into the Electro-Pneumatic Brake system; its use on commuter-style trains made immediate sense.

Still, the original .eng files in the FGW Class 158 download didn't list EP at all - but perhaps MSTS couldn't handle EP (just a guess). But that begged a question: what, actually, do real 158's use? According to this Wikipedia entry, the answer is "Pneumatic, disc." Since all the other Sprinters listed in Wikipedia give the brakes as "Air/EP" I'm taking it that the Pneumatic/disc means an "Air/EP" system.

So I created some more "include" .eng files for this model, this time with the EP values I found in the MT 150 for the Wagon section, and the default Air-twin pipe values for the Engine section that came with the original download.

Et voila! Perfect operation: the EP brakes worked, for a DMU commuter-type application, much better than those heavy diesel engine values. Problem solved! Very Happy

Kind regards,

David

Shawmut

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Re: OR brake values for Class 158 DMU

Post  StephenRWells on Sat 19 Aug 2017, 5:22 pm

Hi David,

Glad you've got it all sorted,

Stephen
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Re: OR brake values for Class 158 DMU

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