[copperpen]

Early experimental and first generation diesels in the UK were indeed vacuum braked as it matched all of the brake fitted rolling stock of the time. Later build rolling stock was air braked and locomotives were changed to fit.

MSTS diesel engines of UK outline do have vacuum brakes that match the stock where required, and can be changed to air brakes. The documentation does not infer that vacuum is the preserve of steam locomotives.

[plainsman]

"PRR BROKEN HOPPER - ORIGINAL "PLAINSMAN"
Friction (
100N/m/s 1 -1mph 0 1
5.1N/rad/s 1 -1rad/s 0 1
)


)

BrakeEquipmentType( "Handbrake, Triple_valve, Auxilary_reservoir, Emergency_brake_reservoir" )
BrakeSystemType( "Air_single_pipe" )
MaxBrakeForce( 50kN )

MaxHandbrakeForce( 35kN )
NumberOfHandbrakeLeverSteps( 100 )

TripleValveRatio( 2.5 )
MaxReleaseRate( 15 )
MaxApplicationRate( 25 )
MaxAuxilaryChargingRate( 5 )
EmergencyResCapacity( 7 )
EmergencyResChargingRate( 5 )
EmergencyBrakeResMaxPressure( 90 )
BrakeCylinderPressureForMaxBrakeBrakeForce( 50 )"
One thing to note. Files sometimes get copied or regurgitated with parameters misapplied or sections get copied inadvertently. I mention this because the file parameters posted in this thread attributed to me, are not in keeping with any files I have released. The friction line is from default MSTS before Joe came out with the initial version of FCalc, so that file is probably from 1999. We have had 20 years to work on MSTS, and some tings that worked one way in MSTS create unintended consequences in OR. Those brake values are also default or 1999 values. I see files all the time that say "physics by Bob Boudoin" and I can't find anything that looks like my work, and they just copied a boilerplate file ID that is not correct. Check releases against at least the V4.5 physics set ( a more "casual" release that made the developer community happy ) and preferably V4.8 or newer. I am working on an OR specific release with several folks at this time. It will be a comprehensive release when finished, so it will be easier to find the appropriate files. Also note, things like the brake pipe hose effective diameter will change braking characteristics dramatically. It isn't a parameter, it is the integrated system!
Here would be the latest brake values for MSTS, for a 129.6 metric ton Bethgon, much heavier than the old PRR hoppers:
MaxBrakeForce( 39.5kN ) MaxHandbrakeForce( 46kN )
NumberOfHandbrakeLeverSteps( 100 )

EmergencyBrakeResMaxPressure ( 110 )
EmergencyResVolumeMultiplier ( 1.461 )
TripleValveRatio ( 2.5 )
MaxReleaseRate ( 0.935 )
MaxApplicationRate ( 0.515 )
MaxAuxilaryChargingRate ( 0.28 )
EmergencyResCapacity ( 2.064 )
EmergencyResChargingRate ( 0.24 )
BrakeCylinderPressureForMaxBrakeBrakeForce( 64 )
Do you see a big difference?I think those recharge rates may be too low in OR, we are still testing and discussing several sections??

[Coolhand101]

plainsman, on 06 February 2019 - 04:07 PM, said:

Here would be the latest brake values for MSTS, for a 129.6 metric ton Bethgon, much heavier than the old PRR hoppers:
MaxBrakeForce( 39.5kN ) MaxHandbrakeForce( 46kN )

Handbrake force is higher than wagon brake force? Also, the brake force for that wagon appears quite low for a 129t hopper wagon. Unless you are using the BF for the wagon tare weight?

Thanks

[copperpen]

We already have a brakepipe volume parameter that works quite well. What difference would a brakepipe diameter make to that?, or are you making a completely different brake system application for OR?.

[steved]

Coolhand101, on 06 February 2019 - 05:30 PM, said:

Handbrake force is higher than wagon brake force? Also, the brake force for that wagon appears quite low for a 129t hopper wagon. Unless you are using the BF for the wagon tare weight?

Thanks

You can set a handbrake tight enough to slide the wheels on a loaded car. The air brakes won't slide the wheels for obvious reasons.

Steve

[Coolhand101]

steved, on 07 February 2019 - 08:10 AM, said:

You can set a handbrake tight enough to slide the wheels on a loaded car. The air brakes won't slide the wheels for obvious reasons.

Steve

Well of course the wheels will slide, your applying the total wagon brake force to one set of wheels or one set of bogie wheels. The slack adjuster allows the handbrake to do this, plus they also have a adjustable bolt to limit the applied force.

In OR and MSTS, you use up to 50% of this value for the same effect, as both sims use handbrakes on all wheels.

Also air brakes can slide the wheels if too much brake force is applied, ie brake compensator set to loaded on an empty wagon.

Thanks

[scottb613]

plainsman, on 06 February 2019 - 04:07 PM, said:

"PRR BROKEN HOPPER - ORIGINAL "PLAINSMAN"

Hi Bob,

Hmm - well there are only so many of us that made PRR Hoppers and listed you as a contributor - I'm guessing I am the guilty party ?

My apologies - sir...

I just checked mine and it seems they are indeed broken...

When I made the model - I'm pretty certain I contacted you directly for the latest approved version of your physics - which I dutifully loaded... It appears at some later date - before upload - I must have played with that feature in Route Riter to update the car physics - and I inadvertently uploaded the result... I just looked at the brake diags in ORTS and there are no brake values displayed for my cars - so I am assuming ORTS is substituting a generic values...

Would you happen to have a link for your latest and greatest - 55 Ton USRA Coal Hopper on friction bearings ?

Thanks and again my humble apologies...

PS: I could use a set for 40 Foot Steel Ice Reefers on friction bearings as well ?
:derisive:

Regards,
Scott