[DirtyRam]

steamer_ctn, on 01 July 2021 - 09:57 PM, said:

Ok, issues with code conflicts have now been sorted, so changes have now been uploaded to latest unstable version.

To confirm variable if required are:
ORTSLengthBogieCentre - length between bogie centres
ORTSLengthCarBody - Length between car ends
ORTSLengthCouplerFace - length between coupler faces.

ORTSNumberAxles - number of axles on the car.
ORTSNumberBogies - number of bogies on the car.

Hey Peter, this is how I've set it up and called it - Comment ( Derailment Coefficient ).
Is this suitable for .wag files

Comment ( "ResistancePC3BayOffsetHop99.2t.inc" )

Comment ( 26.74t-us Empty 110t-us Full )
Mass ( 99.2t-us )

ORTSAdhesion ( ORTSCurtius_Kniffler ( 7.5 44 0.161 0.7 ) )

Comment ( Derailment Coefficient )
ORTSLengthBogieCentre ( 30ft )
ORTSLengthCarBody ( 41ft )
ORTSLengthCouplerFace ( 45.46ft )
ORTSNumberAxles ( 4 )
ORTSNumberBogies ( 2 )
minimum turning radius

Comment ( Level Resistance )
ORTSBearingType ( Friction )
ORTSDavis_A ( 244.95lbf )
ORTSDavis_B ( 4.4640lbf/mph )
ORTSDavis_C ( 0.048849lbf/mph^2 )

Comment ( Assumptions - FreightCar Standard -
Speed - 65mph, Friction Bearing, 4 axles,
Frontal Area - 97.78ft^2, Wagon Weight - 99.2 ton (US) )
Davis speed: 46mph, RMS Error: 10.07N, Max Error: 37.08N @ 6mph

Comment ( Wind Resistance )
ORTSWagonFrontalArea ( 97.78ft^2 )
ORTSDavisDragConstant ( 0.0012 )

Comment ( Curve Resistance )
CentreOfGravity ( 0in 65.20in 0in )
ORTSTrackGauge ( 4ft 8.5in )
ORTSRigidWheelBase ( 5.65ft 3.6in )
ORTSUnbalancedSuperelevation ( 2 9/16in )

Just had a thought while doing some engines, minimum turning radius.
Thanks, Mike

[steamer_ctn]

DirtyRam, on 13 August 2021 - 04:35 AM, said:

Hey Peter, this is how I've set it up and called it - Comment ( Derailment Coefficient ).Is this suitable for .wag files

The definition of the derailment coefficient parameters seems fine.

A couple of general comments.

Unless this is a locomotive with a higher then default adhesion, I wouldn't bother putting an Adhesion parameter in (though nothing to stop you putting the default curve values in as you appear to have done).

DirtyRam, on 13 August 2021 - 04:35 AM, said:

ORTSUnbalancedSuperelevation ( 2 9/16in )

I would suggest using a decimal value of inches in this one, ie 2.56in.

I don't think that value you have used will be read correctly by OR.

The log file sometimes presents error message that will be helpful to ensure that there are no problems with any parameters.

DirtyRam, on 13 August 2021 - 04:35 AM, said:

Just had a thought while doing some engines, minimum turning radius.

What did you have in mind with this?

[ATW]

I like where this may be going, good ideas.

Can wheel size play a good role as some freight cars like some empty autoracks with small wheels are known to easily stringline over a curve or switch when too much force is pulling or pushing them or pulling heavier resistant tonnage behind them at curves.

I like the idea for minimum turning radius for curves. My thought for turning radius is minimum curve angle stock can negotiate vs max slack force.

[steamer_ctn]

ATW, on 14 August 2021 - 06:37 AM, said:

Can wheel size play a good role as some freight cars like some empty autoracks with small wheels are known to easily stringline over a curve or switch when too much force is pulling or pushing them or pulling heavier resistant tonnage behind them at curves.

The physics of derailments is quite complex, and two principal factors, in addition to the lateral forces, are the wheel profile (angle of attack) and the track condition.

Both of these factors are very complex to model (in OR code) and may the relevant real world information may not be readily available for the average user to find.

Hence the model for derailment that has been introduced is a more generic model that attempts to take these factors into account without specifically using them for the calculation.

To improve the "accuracy" of this feature, perhaps the derailment coefficient (L/V ratio) could be used as the "set point" for notification and some reaction from OR. However again I haven't found a huge amount of detail about what derailment coefficients that railways use as a working standard.

Perhaps you could do some research and provide some survey results on relevant derailment coefficient levels that railways operate to.

ATW, on 14 August 2021 - 06:37 AM, said:

I like the idea for minimum turning radius for curves. My thought for turning radius is minimum curve angle stock can negotiate vs max slack force.

The derailment coefficient is used by railway companies to determine "appropriate speed limits" around curves. This to a certain effect would also apply to minimum curve radius, as railway companies would determine the maximum speed that a car can go around a curve.

Hence if the radius is too small, and the maximum speed limit is too prohibitive for the car, then I believe that they would set this as the "minimum curve radius" for this car.

[cjakeman]

This new feature should look good - perhaps we ought to have a short video clip to show it off. If we're quick, there's still time to add that to the video for the Version 1.4 release.

Can we have a volunteer ? Please?

[ATW]

steamer_ctn, on 15 August 2021 - 02:15 AM, said:

The physics of derailments is quite complex, and two principal factors, in addition to the lateral forces, are the wheel profile (angle of attack) and the track condition.

Both of these factors are very complex to model (in OR code) and may the relevant real world information may not be readily available for the average user to find.

Hence the model for derailment that has been introduced is a more generic model that attempts to take these factors into account without specifically using them for the calculation.

To improve the "accuracy" of this feature, perhaps the derailment coefficient (L/V ratio) could be used as the "set point" for notification and some reaction from OR. However again I haven't found a huge amount of detail about what derailment coefficients that railways use as a working standard.

Perhaps you could do some research and provide some survey results on relevant derailment coefficient levels that railways operate to.



The derailment coefficient is used by railway companies to determine "appropriate speed limits" around curves. This to a certain effect would also apply to minimum curve radius, as railway companies would determine the maximum speed that a car can go around a curve.

Hence if the radius is too small, and the maximum speed limit is too prohibitive for the car, then I believe that they would set this as the "minimum curve radius" for this car.

It's better then nothing if its complex. Wheels are not that important for this but how users set the physics an how the code cooperates. But I need to see what we have now. But my big goal is how much pulling or pushing forces around curves play with example of forces rising when brake resistance increases buff loading like we normally see in coupler force info.

May I ask for a template example for this an how users set the physics in the WAG section? Is it in MonoGame releases yet or am I missing something?

I like to test this out more since I missed a lot when working in this RR meltdown.

[steamer_ctn]

ATW, on 15 August 2021 - 01:12 PM, said:

It's better then nothing if its complex. Wheels are not that important for this but how users set the physics an how the code cooperates. But I need to see what we have now. But my big goal is how much pulling or pushing forces around curves play with example of forces rising when brake resistance increases buff loading like we normally see in coupler force info.

The pulling or pushing force is determined in the coupler section of the OR code. This is fed into the derailment coefficient. I am not certain how accurate the coupler force calculation is, and also how it reacts to braking.

ATW, on 15 August 2021 - 01:12 PM, said:

May I ask for a template example for this an how users set the physics in the WAG section?

It will use wagon sizes as a default, alternatively you can add the parameters indicated here.

ATW, on 15 August 2021 - 01:12 PM, said:

Is it in MonoGame releases yet or am I missing something?

It has only just been released in the unstable version so I suspect not.

[ATW]

steamer_ctn, on 15 August 2021 - 08:45 PM, said:

The pulling or pushing force is determined in the coupler section of the OR code. This is fed into the derailment coefficient. I am not certain how accurate the coupler force calculation is, and also how it reacts to braking.


It will use wagon sizes as a default, alternatively you can add the parameters indicated here.


It has only just been released in the unstable version so I suspect not.

Thanks for the info I will take a look an test the un stable version.

RR I work for coefficient to derail in pushing or pulling forces determine how many axles of power (Tractive Effort) you can have on the headend, middle or rear as well as car weight averages an tonnage restrictions behind the given car. So have a empty closer to the headend an exceed the tonnage behind it which can be heavy loads bunching against it vs run in force or heavy dynamic/independent braking we got a problem an risk. Now if you have helpers the empty low tonnage car must be in middle from conflicting high forces or on the rear of helper.

If you use ORTS an watch coupling forces head to rear or towards helpers you see a positive an negative... if you try pulling take a look at average forces before you set train brakes bailing off independents you see a difference an change in coupler forces an will indeed see a change pulling while the rear multiple cars have strong handbrakes set. If you are bunching with dynamics or independents you see high coupler forces rise unless you set train brakes for cars to brake an help reduce high hard coupler forces with tonnage pushed against train.

So around tight curves we know friction an forces is increased depending on radius/degree of the curve. Coupler breaks limits may be strong set but is it stronger then the tonnage it can take bunched or pulling even around tight curves? So lateral forces at bogies an wheels need their limits of force too. But I will look at what we have now.

Even if it makes 1.4 the code will do it by wag parameters only so it won't conflict with problems users may run into if code is not fully complete or accurate but lay in user set physics?

[Lamplighter]

Driving vehicles use two parameters for the number of axles: ORTSNumberAxles and ORTSNumberDriveAxles. How will the parameters for the derailment coefficient be solved?
For example, 4-axle el. the locomotive has ORTSNumberAxles (0) and ORTSNumberDriveAxles (4).
Railcar with axle arrangement B2 then ORTSNumberAxles (2) and ORTSNumberDriveAxles (2).

[Laci1959]

Quote

So around tight curves we know friction an forces is increased depending on radius/degree of the curve.

To that I would add overshoot and speed.
When the train is traveling at a certain speed, the overlift and the outward centrifugal force balance each other out. That is, the wheel only has rolling resistance.
If the speed is lower than this, the wheel will move inwards and the track flange will rub more and more strongly on the side of the inner rail fiber. the slower the more.
If the speed is above this value, it is only the other way around, ie the wheel is heading.
Unfortunately, my knowledge of track construction is quite limited in this regard.