[hugoakio]

I experiencing, with the advanced adhesion, some problems with wheelslip in modern locomotives (GE C44-9WM and Ac4400CW). I'm running with this locomotive for years in real life and the adhesion behavior in the OR doesn't even look like the real locomotive.
I'm using the follow settings:
ORTSadhesion ( ORTSCurtius_Kniffler ( 4.500 46 0.185 0.7 ) ) (tried countless values)
ORTSadhesion ( ORTSSlipWarningThreshold ( 70 ) )

ORTS ( ORTSWheelSlipCausesThrottleDown ( 0 ) )
ORTS ( ORTSEmergencyCausesThrottleDown ( 1 ) )
ORTS ( ORTSEmergencyEngagesHorn ( 1 ) )
ORTS ( ORTSAntislip ( 1 ) )

AntiSlip ( 1 )

Also, I run with adhesion move average filter size at 10, Adhesion factor correction at 200% (tried values from 100% to 200%), and Adhesion ramdom at 0%.
In my computer OR runs between 50 and 120 FPS with no significant lags or fast drops.


In step grades, where I have to release train brakes, up the throttle to notch 2 or 3, waiting the brake shoes realease and than release independent brake slowly
occurs an annoying (and unreal) wheelslip and Tractive Effort oscillation, that only occurs with Advanced adhesion mode activate.

So, there's any way to keep the benefits of OR parameters (like ORTSBrakeShoeFriction, ORTSDavis, ORTSMaxTractiveForceCurves, etc) and use the adhesion equation of the unchecked Advanced adhesion mode? Or even eliminate completely the wheelslip?

Thank you.

[R H Steele]

The problem may not be with any specific item or configuration but with a combination of things. Hard for me to tell without knowing more. What formula/method was used to construct the ORTSMaxTractiveCurves? and are you using the correct power/weight data for the locomotives. Couple of items did catch my eye.

1. The last two values in the CurtiusKniffler numbers deviated from the standard 0.161 0.7 values. My understanding is that these two values are not worth changing...there is a thread here at Elvas where Joe Realmuto and Bob Boudoin have a conversation about that. If I can find it I'll post it in this thread. Meanwhile use the search term "CurtiusKniffler" .. or some variation and see what comes up.

2. From another thread I'm aware of around 2016 or thereabouts, it was mentioned that the ORTS Antislip parameter was not really an ORTS parameter, and that using it or the MSTS version Antislip ( 1 ) only served to "turn off" the advanced adhesion mode in Open Rails. This may have subsequently changed in coding and should be verified.

I'll try to find some more relevant information, meanwhile, be patient, I'm sure some more knowledgeable members than myself will eventually see your post and provide some help.

[R H Steele]

Here's the link for Joe Realmuto's discussion of CK values, looking it over again it appears the 3rd CK value relates to speed, especially high speed, so for NA freight which I mainly run 0.161 would be default, however, if you are running high speed trains then an adjustment of this value appears reasonable.
Curtius Kniffler

[hugoakio]

 R H Steele, on 24 January 2021 - 02:56 PM, said:

The problem may not be with any specific item or configuration but with a combination of things. Hard for me to tell without knowing more. What formula/method was used to construct the ORTSMaxTractiveCurves? and are you using the correct power/weight data for the locomotives. Couple of items did catch my eye.

1. The last two values in the CurtiusKniffler numbers deviated from the standard 0.161 0.7 values. My understanding is that these two values are not worth changing...there is a thread here at Elvas where Joe Realmuto and Bob Boudoin have a conversation about that. If I can find it I'll post it in this thread. Meanwhile use the search term "CurtiusKniffler" .. or some variation and see what comes up.

2. From another thread I'm aware of around 2016 or thereabouts, it was mentioned that the ORTS Antislip parameter was not really an ORTS parameter, and that using it or the MSTS version Antislip ( 1 ) only served to "turn off" the advanced adhesion mode in Open Rails. This may have subsequently changed in coding and should be verified.

I'll try to find some more relevant information, meanwhile, be patient, I'm sure some more knowledgeable members than myself will eventually see your post and provide some help.

Hi R H Steele, thank you for the reply.
I made another test, based in your answer, but nothing has changed. Here's the video and the wheelslip problem. Note that as I release the independent brake the Tractive Effort starts to oscillate, wath doesn't happen on the real world, at least in modern diesel locomotives.

https://www.youtube....eature=youtu.be

1. I adjusted my CurtiusKniffler for 0.161 0.7.
2. I ereased all Antislip commands.
3. To construct the tractive effort curve, I had access to the Operator Manual, Maintenance Manual, some videos of the display of the GE AC4400 operating and had conversations with a engineer friend of mine. So I colleted all the values and recriated the Tractive Effort curve at excel. As soon as it looked like the Manual curve, I exported the values of tractive Effort for all notches.

Here's the power section of .eng file:
Type ( Diesel ) Comment ( Tipo de Tração Primária - Diesel / Electric / Steam )
MaxPower ( 3355.64kW ) Comment ( Potência Máxima Disponível para Tração 4386hp 7FDL16 )
MaxForce ( 889.645kN ) Comment ( Esforço de Tração Máximo na partida em 46,5% de Aderência )
MaxContinuousForce ( 784.893kN ) Comment ( Esforço de Tração Máximo em regime contínuo em 38,5% de Aderência )
MaxVelocity ( 80 ) Comment ( Velocidade Máxima )
MaxCurrent ( 90718 ) Comment ( Corrente Máxima do Motor Elétrico de Tração 2000A = 200 KLBS = 90.718 KGF )
WheelRadius ( 42in )
Sanding ( 13 )
NumWheels ( 6 )

Diesel (
IdleRPM ( 335 )
MaxRPM ( 1047 )
StartingRPM ( 335 )
StartingConfirmRPM ( 335 )
ChangeUpRPMpS ( 20 )
ChangeDownRPMpS ( 15 )
RateOfChangeUpRPMpSS ( 20 )
RateOfChangeDownRPMpSS ( 15 )
MaximalPower ( 4545hp )
IdleExhaust ( 2 )
MaxExhaust ( 5 )
ExhaustDynamics ( 3 )
ExhaustDynamicsDown ( 1.2 )
ExhaustColor ( FF404040 )
ExhaustTransientColor( FF404040 )
Comment ( Estimates of GE FDL16 gross 4545HP )
DieselPowerTab (
0 0hp
335 15hp
1047 4545hp
)
Comment ( Consumo de combustível Rpm x Litro/h )
DieselConsumptionTab (
0 0
335 14.71
425 42.51
596 87.82
746 191.80
811 271.56
897 387.19
962 497.02
1002 607.28
1047 719.57
)
ThrottleRPMTab (
0 335
12.5 436
25 576
37.5 884
50 884
62.5 991
75 991
87.5 991
100 1047
)
MinOilPressure ( 43 ) Comment ( Pressão Mínima do Óleo em PSI )
MaxOilPressure ( 111 ) Comment ( Pressão Máxima do Óleo em PSI )
IdleTemperature ( 76.67 ) Comment ( Temperatura na marcha lenta do Motor Diesel em Celsius )
OptTemperature ( 82.23 ) Comment ( Temperatura nominal do Motor Diesel em Celsius )
MaxTemperature ( 115.5 ) Comment ( Temperatura máxima do Motor Diesel em Celsius )
Cooling ( 3 ) Comment ( Resfriamento 0: Não 1: Mecânico 2: Com resposta atrasada 3: Proporcional )
TempTimeConstant ( 240 ) Comment ( Tempo para mudança de temperatura em segundos )
)
)

ORTSMaxTractiveForceCurves (
0 ( 0.0 0.0 50 0.0 )

Comment ( Ponto 1 ~ 12.676% ~ 304hp )
0.125 (
0 66547.92
1.28 67352.07
2.08 55897.9
2.77 37265.27
3.47 29518.01
4.16 28439.28
4.86 27458.62
5.55 23535.96
6.94 17651.97
8.33 14709.97
9.72 11767.98
11.11 5883.99
13.88 4903.32
17.22 5883.99

)

Comment ( Ponto 2 ~ 36.62% ~ 609hp )
0.250 (
0 229426.57
0.64 228779.33
0.88 228790.12
0.89 228498.86
0.92 227669.22
1.29 209793.66
2.04 143785.1
2.58 116355.9
3 98497.99
3.47 88259.85
4.16 74530.54
4.86 60801.23
5.55 56878.57
6.94 46091.25
7.5 44816.39
7.77 45274.94
8.33 34323.27
10.55 29419.95
11.11 28439.28
12.5 26477.95
13.88 25497.29
15.27 21574.63
16.94 19319.1

)

Comment ( Ponto 3 ~ 57.75% ~ 1269hp )
0.375 (
0 425559.57
1.29 421548.65
2.08 313812.8
2.77 235359.6
3.47 186326.35
4.16 151022.41
4.72 138871.97
5.55 117679.8
6.25 102969.82
6.94 89240.51
7.63 85317.85
8.33 78453.2
9.72 65704.55
10.27 65253.44
11.11 58839.9
12.5 53936.57
15.27 39226.6
16.66 31479.34

)

Comment ( Ponto 4 ~ 66.90% ~ 1779hp )
0.500 (
0 550643.39
1.38 500139.15
2.08 466796.54
2.77 353039.4
3.47 276547.53
4.16 235359.6
4.86 203978.32
5.55 182099.68
6.25 161809.72
6.94 142196.42
7.63 127486.45
8.05 117679.8
9.72 98066.5
10.55 91201.84
11.38 88259.85
12.22 79139.66
13.61 72833.98
15.27 60801.23
16.66 56878.57

)

Comment ( Ponto 5 ~ 78.87% ~ 2389hp )
0.625 (
0 667244.46
2.08 603108.97
2.77 502100.48
3.47 410898.63
3.75 382459.35
4.41 318716.12
4.86 292238.17
5.55 259876.22
5.83 235938.19
6.38 214804.86
6.94 204958.98
7.63 183384.35
8.33 169655.04
9.72 145138.42
11.11 129447.78
11.8 117679.8
12.5 112776.47
13.88 98066.5
15.27 89240.51
16.66 83356.52

)

Comment ( Ponto 6 ~ 88.03% ~ 3150hp )
0.750 (
0 667244.46
2.08 603108.97
2.77 502100.48
3.47 410898.63
3.75 382459.35
4.41 318716.12
4.86 292238.17
5.55 259876.22
5.83 235938.19
6.38 214804.86
6.94 204958.98
7.63 183384.35
8.33 169655.04
9.72 145138.42
11.11 129447.78
11.8 117679.8
12.5 112776.47
13.88 98066.5
15.27 89240.51
16.66 83356.52

)

Comment ( Ponto 7 ~ 93.66% ~ 3860hp )
0.875 (
0 762957.37
2.77 735498.75
3.47 661948.87
3.63 616347.95
3.76 601606.59
3.81 593738.72
3.83 588666.72
4.16 558979.05
4.36 534393.77
4.72 500139.15
5.55 421685.95
6.25 374614.03
6.94 338329.42
7.77 315009.21
8.61 280195.6
9.86 254041.26
10.27 227514.28
11.11 205939.65
11.66 196133
12.77 181423.02
14.16 169655.04
15.16 163202.26
16.66 137293.1


)

Comment ( Ponto 8 ~ 100% ~ 4545hp )
1 (
0 784532
1.73 784532
3.69 733243.22
3.88 702156.14
4.33 658957.84
4.86 597832.99
5.27 562401.57
5.55 535256.76
6.25 460912.55
6.66 438896.62
6.94 411879.3
8.05 346106.09
8.61 333426.1
10 284392.85
11.11 254972.9
12.5 225552.95
13.88 205939.65
14.44 196133
16.66 169655.04
)
)

[hugoakio]

 R H Steele, on 24 January 2021 - 05:47 PM, said:

Here's the link for Joe Realmuto's discussion of CK values, looking it over again it appears the 3rd CK value relates to speed, especially high speed, so for NA freight which I mainly run 0.161 would be default, however, if you are running high speed trains then an adjustment of this value appears reasonable.
Curtius Kniffler

Sorry, i don't have access to this topic. Hers's appear "[#10342] We could not determine which forum this topic is in" error

[engmod]

Are you using sand?, all of the ac machines have automatic sanding.

Also, your percentage of power per notch does not look prototypical.

Your problem started at n3 which is 58% power with no sand, a problem waiting to happen.

[engmod]

>Sorry, i don't have access to this topic. Hers's appear "[#10342] We could not determine which forum this topic is in" error

That is a software development thread, so limited audience.

[darwins]

With regard to wheelslip there are three features that I would like to see working as they do in real life. I have commented on them elsewhere at various times, but this also seems like a relevant thread to mention them in.

The first is the modern "antislip" control that applies to electric and diesel electric locomotives (and possibly more recent hydraulic transmissions too). Very simply the driver puts the throttle in a position - if before reaching that power output the engine begins to slip, power is automatically reduced. The throttle itself does not change position in the cab and the loco will continue to try to reach the set power output (but each time a slip is about to occur reduce the power to the wheels).


The other two are essentially part of the braking system and I hope the will be added as work continues on braking.

One is the "antislip brake" - something that predated the modern electronic antislip control. The driver of a diesel or electric loco has a button that when pressed puts 10 or 15 psi into the locomotive brake cylinders. This is often enough to grip the wheels and prevent slipping.

The final one is "WSP" or wheel slide protection that prevents wheels from locking and skidding when braking - the railway equivalent of ABS on a motor car. Modern versions of this use electronic sensors. One of the earliest versions was introduced on the London Underground in the 1930s. Following the introduction of EP brakes - lightly loaded trailer cars were starting to suffer 'flats' due to the improved braking. To solve this problem mercury retarders were installed which acted as accelerometers. If the car was slowing down too quickly they reduced the pressure in the brake cylinder.

[Coolhand101]

 darwins, on 25 January 2021 - 01:34 AM, said:

Very simply the driver puts the throttle in a position - if before reaching that power output the engine begins to slip, power is automatically reduced. The throttle itself does not change position in the cab and the loco will continue to try to reach the set power output (but each time a slip is about to occur reduce the power to the wheels).

This was mentioned a few years ago, it would be great to see this implemented!

 darwins, on 25 January 2021 - 01:34 AM, said:

One is the "antislip brake" - something that predated the modern electronic antislip control. The driver of a diesel or electric loco has a button that when pressed puts 10 or 15 psi into the locomotive brake cylinders. This is often enough to grip the wheels and prevent slipping.

The actual wheelslip implementation needs to be altered for this to work prototypical. Even placing 10 to 15 PSI of the straight air brake makes no difference to reducing/preventing wheelslip.

 darwins, on 25 January 2021 - 01:34 AM, said:

The final one is "WSP" or wheel slide protection that prevents wheels from locking and skidding when braking - the railway equivalent of ABS on a motor car.

This would be a another great implementation. For the moment, I'm not sure if any of the anti-slip parameters allow the sensitivity of the wheelside to be reduce!


To the OP. For my realistic adhesion. I check 'Advanced adhesion model', 'Adhesion moving average filter' size to 10. Then 'Adhesion factor correction' to 100%, 'Adhesion factor random change' between 0 and 5%, 'Adhesion proportional to rain/snow/fog' checked.

My settings haven't changed for years. However, the locos/traction I drive in the UK are not as powerful as US locos. But the above settings do work for me 100%.

Thanks

[hugoakio]

 engmod, on 24 January 2021 - 10:39 PM, said:

Are you using sand?, all of the ac machines have automatic sanding.

Also, your percentage of power per notch does not look prototypical.

Your problem started at n3 which is 58% power with no sand, a problem waiting to happen.

was
Sand makes no difference for this case, i already test yet. Also, in real life engineer starts to use sand at notch3. In my video, I opened notch 2, which represent 26% according GE. The "36%" was taken from another locomotive and i forget erase for this locomotive.
And yes, looks weird but that's how the power is distributer per notch in GE Locomotive. It's how the manufacturer says and happens on the real locomotive:

N1: 6800 kgf
N2: 23600 kgf
N3: 43395 kgf
N4: 56150 kgf
N5: 68040 kgf
N6: 70900 kgf
N7: 77800 kgf
N8: 90000 kgf (Here i'm translate this starting point to aproximate 80000kgf, because the locomotive never do 90000kgf at 0km/h. In fact, the maximum tractive effort that i've heard is 86000kgf)

 darwins, on 25 January 2021 - 01:34 AM, said:

With regard to wheelslip there are three features that I would like to see working as they do in real life. I have commented on them elsewhere at various times, but this also seems like a relevant thread to mention them in.

The first is the modern "antislip" control that applies to electric and diesel electric locomotives (and possibly more recent hydraulic transmissions too). Very simply the driver puts the throttle in a position - if before reaching that power output the engine begins to slip, power is automatically reduced. The throttle itself does not change position in the cab and the loco will continue to try to reach the set power output (but each time a slip is about to occur reduce the power to the wheels).

it would be great have this. I would complement that the reduction is very, but very smooth, in terms of how locomotive avoid train internal bumps. For example, take a look in this video from 5:48. In the same situation in OR, if I don't do the reduction in my effort curve, for sure my train stalls.

https://www.youtube....index=19&t=336s