[cesarbl]

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Still seeing some unusual indications from the simulated wheel adhesion though, it will still get stuck at unreasonably high values (for example, the MSTS Dash 9 reading 33% ahdesion while at a complete standstill). That can't be doing anything good for the stability of the model and there has to be a simpler way to avoid that than just throwing more substeps at the system. Surely it would be obvious without substepping that a force of 0 should require and ahdesion of 0?

At zero speed, adhesion is treated as a static adhesion coefficient, such that all force is transmitted to rails without any creep. This is what Polach formula says, because optimal wheel creep tends to zero as speed goes to zero.

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Maybe some simplifying assumptions can be made, or the old model could be user-selected (though it could use some modifications to give more reasonable wheel creep)

Unfortunately not, the computational cost of the model comes from the bigger number of substeps required, and not from the formula itself. Any model which gives low wheel creep will suffer from that problem

[steamer_ctn]

pschlik, on 25 October 2023 - 04:36 PM, said:

Had another moment to test today. Numbers of substeps are more tame now, and in combination with more gradual change frame time pacing is definitely more consistent now. Also remained fairly stable even at 300% sim speed so the algorithm seems to be running fast enough at the moment. Still seeing some unusual indications from the simulated wheel adhesion though, it will still get stuck at unreasonably high values (for example, the MSTS Dash 9 reading 33% ahdesion while at a complete standstill). That can't be doing anything good for the stability of the model and there has to be a simpler way to avoid that than just throwing more substeps at the system. Surely it would be obvious without substepping that a force of 0 should require and ahdesion of 0?

Thanks for the feedback.

I am taking from this that you think that the Polach adhesion substep rate is "about right" now, is this correct?

Can you expand in more detail on how to duplicate the " it will still get stuck at unreasonably high values (for example, the MSTS Dash 9 reading 33% ahdesion while at a complete standstill)" scenario? The old model always had the maximum adhesion (given by locomotive adhesion) occurring at zero speed.

pschlik, on 25 October 2023 - 04:36 PM, said:

And this might be related but whenever I apply power ammeters are reading NaN! (Dynamic braking is fine though?)

Ok I can duplicate this, and I now roughly when this started to ok, but I can't see any obvious issues. I will investigate further (I am off on holidays for a week on Monday my time) so I am not sure whether I can fix it before then.

pschlik, on 25 October 2023 - 04:36 PM, said:

At this point, I'm not convinced that this model is a fool's errand but even after working through the weird stuff, it will clearly need more computing power than the previous model. Maybe some simplifying assumptions can be made, or the old model could be user-selected (though it could use some modifications to give more reasonable wheel creep), but I don't know the details and it's not the right time to worry about that anyway.

I would prefer not to have multiple user selected models, we should strive for the most efficient and realistic performance (this may still need to be determined, and it could be either the new model working at an acceptable level, or reverting to the old model)..

[Traindude]

Just passing this word along--I've discovered a bug that may be associated with the new adhesion model.

[steamer_ctn]

Traindude, on 28 October 2023 - 01:19 PM, said:

Just passing this word along--I've discovered a bug that may be associated with the new adhesion model.

I can't open the post, can you please check it, or post some of the details in this thread. Also can you please recheck it with the latest Unstable version.

[steamer_ctn]

pschlik, on 25 October 2023 - 04:36 PM, said:

And this might be related but whenever I apply power ammeters are reading NaN! (Dynamic braking is fine though?)

I think that I have identified the issue, and corrected it in the latest Unstable version.

Can you please check and confirm.

[Traindude]

steamer_ctn, on 28 October 2023 - 02:07 PM, said:

I can't open the post, can you please check it, or post some of the details in this thread. Also can you please recheck it with the latest Unstable version.

Try this one. Yes, these were both using U2023.10.26-1752.

[steamer_ctn]

Given that there has been no further feedback in this thread for the past week, I am assuming that any outstanding bugs have now been corrected for this addition. Therefore it is proposed to release it in the next few days.

It is also suggested that users consider the adhesion settings for their diesel locomotives.

[pschlik]

Sorry I didn't keep up with this change much, Cities Skylines 2 came out, I got a new quite draining project at work, then spent a whole weekend sick. OR got put on my backburner.

With the new adhesion model, I'm not noticing anything too weird at the macro scale. Of course, if I stare at the F5 debug things look weird with numbers jumping around and I'm still wondering how we'll be able to use this output to drive more realistic wheel slip protection when that time comes. Sometimes the data just looks a bit too erratic to reliably determine when the locomotive is close to slipping. Granted it's not like I've started thinking about building new WSP code so it's probably too early to act on that suspicion.

[Weter]

With last (2023.10.20) testing version, some locomotives have become too sleepy and stuck in long curves with even 11 cars passenger trains.
I'll look for *.eng-files to attach. Switching to simple adhesion model helps, making me sad.

[steamer_ctn]

pschlik, on 07 November 2023 - 04:18 PM, said:

With the new adhesion model, I'm not noticing anything too weird at the macro scale.

Thanks for the feedback.

pschlik, on 07 November 2023 - 04:18 PM, said:

Of course, if I stare at the F5 debug things look weird with numbers jumping around and I'm still wondering how we'll be able to use this output to drive more realistic wheel slip protection when that time comes. Sometimes the data just looks a bit too erratic to reliably determine when the locomotive is close to slipping. Granted it's not like I've started thinking about building new WSP code so it's probably too early to act on that suspicion.

The parameter is recalculated many times per second, so it will tend to vary quite a bit. The HUD value is meant as debug value, and not as a "stable" value as such. If you want to use this parameter for another feature, you may need to put a smoothing function in to reduce the variation.

Weter, on 07 November 2023 - 06:14 PM, said:

With last (2023.10.20) testing version, some locomotives have become too sleepy and stuck in long curves with even 11 cars passenger trains.
I'll look for *.eng-files to attach. Switching to simple adhesion model helps, making me sad.

The Polach adhesion changes will not have moved into the Testing version yet, so it shouldn't be creating the issues that you are describing.