[cesarbl]

I am currently working on the advanced adhesion model used in OpenRails. My idea is to have a single accurate model that works for all wagons and types of locomotives.
I have identified and corrected some issues:

• Wheel radius was not taken into account in calculations. As wheel radius is usually in the order of magnitude of 1m, this had a minimal impact.
  
• The minimum inertia moment was too high.
  
• I removed some tentative fixes that eliminated the contribution of wheel inertia to train speed. This had to be added because of the high inertia.
  
• During wheelslip the adhesion coefficient was reduced to zero. Experimental tests suggest that the real figure is a 30%-50% of total adhesion. The formula has been corrected to reflect this.
  
• The adhesion integration time has been reduced, removing the need of an stability correction (to be more carefully ensured).

It is going to be challenging to keep backwards compatibility, as some formulas were wrong, but I'll ensure everything works as before to a reasonable extent. I hope I can achieve it by reducing the default moment of inertia.

Any feedback is welcome. Please take into account that I haven't yet reduced the default inertia, so results will be inaccurate for locomotives without ORTSInertia().

I'd like to implement slip control too.

[Laci1959]

Hello.

I am very pleased with this.
A question. For vehicles with a mixed axle formula, does OR take into account that the driven wheel has an animation and the running wheel does not? The first shaft has a drive, the second and third do not. This must be set when creating the model. I read about this on msts.steam4me.net. I also searched for a link but now I can't find it.
Of course, you need to set ORTSNumberAxles, ORTSNumberDriveAxles, ORTSDriveWheelWeight properly.

Sincerely, Laci1959

[Weter]

Hello.
In timetable mode, if player's train forms another train, there might be, the complex adhesion model will fail, and train can't be started, because of instant wheel slipping from first throttle position. (As rails would be oiled)
Only turning to simple adhesion model will help then.

[NickonWheels]

A major constraint is time compression, where at 150% adhesion still works fine, but go higher and it decreases, at least for the lead locomotive. The higher, the more off-value.

[Weter]

Yes. I did acceleration for not to wait when 15 minutes of "inactivity" period ends

[cesarbl]

Yes, probably we should switch to the simple adhesion model when accelerating simulation time, as that model is not so time critical.

[darwins]

cesarbl, on 03 April 2022 - 02:34 AM, said:

Yes, probably we should switch to the simple adhesion model when accelerating simulation time, as that model is not so time critical.

That sounds like an excellent idea.

[Weter]

Sounds as very reasonable, clever and good idea.
As during accelerated time operation, player train behaves awful, when moving.

AI trains can bump buffers of overshoot couplings as well, in hi acceleration rates.

[engmod]

I too am looking forward to the outcome of this effort.
Up to this point I have only used the simple adhesion model as the advanced model did not work well enough for me.

[pschlik]

Improvements to the adhesion model are a welcome thing in my book. Especially if there is interest in modeling wheel slip protection properly. As it stands right now, driving in inclement weather just isn't very enjoyable as you have to fight the train so much more than you should to handle slips.