Milwaukee Road Electric Physics - ORTS Upgrade?

[PerryPlatypus]

Have any of the knowledgeable physics folks attempted to upgrade the various Milwaukee electrics in the file library to give them realistic, ORTS-compatible physics? I'm specifically thinking of the Little Joes and Boxcabs, but would also be nice to see an improvement for the Bipolars, Steeple cabs, and Quills. I have wanted to make some high quality activities that utilize the various Milwaukee routes (making use of the best Milwaukee and either late NP or early BN locomotives available for ORTS), but most of the electrics are almost un-usable due to their MSTS-style physics - primarily due to poor adhesion (which is generally due to the locos being split into multiple overlapping WAGs, and back in the MSTS days if you set the weight of a WAG very low, it did not compromise adhesion). I believe I could handle the majority of things on the "motive" side, but with braking I would need some major assistance.

Obviously there would be some shortcomings related to the handling of series vs. parallel throttle positions (unless there is a way to mimic this in ORTS that I am not aware of), but I think we could achieve something WAY better than the default physics these locomotives came with. Anyone willing to help?

[pschlik]

For those old DC electrics in particular, the way they work deviates enough from a modern locomotive that trying to simulate one with tractive effort curves is going to miss something. There's the whole issue that old electrics work on constant voltage principles rather than constant power so you can't make one tractive curve then interpolate it down for lower settings, each power setting would need a totally different curve to make any sense. And there's absolutely nothing in place to account for field weakening or motor connection changes.
Then I don't think it's possible at all to give an accurate interpretation of the dynamic brakes as I recall many DC electrics are more involved than 'more dynamic brake lever = more dynamic brake force'. Best case you run a more detailed simulation externally and then turn the results of that into a lookup table that can be entered as tractive effort curves, then give up for the finer details.

These are the sorts of locomotives where it's easier to simulate the circuitry (input simulation) than it is to (try to) skip all that and simulate the resulting force directly (output simulation). But 'real' electrical simulation is still some time away-I've done an immense amount of research and have a good understanding of the (large) variety of features such a simulation would need, yet there's plenty to do before working on that.

[PerryPlatypus]

Phillip,

I do understand that what can be achieved right now in the current limitations of ORTS is not an accurate modeling of DC electrics, and you obviously know more than I do about all the intricacies of why. However, I think even within the current ORTS code limitations we can achieve something FAR more accurate and desirable than the original physics associated with these electrics in the file library. If proper simulation of DC electrics was something likely to be introduced into the ORTS platform in the coming months or even within the next year then I wouldn't bother trying. But if that's likely not going to happen that soon, then I think many users would appreciate an "intermediate" physics upgrade to these locomotives - something that is still a massive leap forward from the original files, even if it still has minor or moderate shortcomings. It's currently so bad that you can't run a heavy freight over the mountain with anything even REMOTELY close to realistic tonnage ratings, because you end up with all sorts of hyper wheelslip / adhesion issues.

[CSRX]

I recently just redownloaded and installed the MILW Coast Division route, that runs between Che Elum and Othello, so it would be pretty cool to have up to standard physics for the electric locomotives. Mainly because, diesels look a little strange on the line with the overhead wire system.

[R. Steele]

Intermediate improvements in the electric's physics would be helpful....especially for adhesion/traction.

[l.k.]

Perhaps it would be useful to talk to our Polish, Italian or French friends about it?

All three countries have extensive DC electrifications and there is an active Open Rails scene in all three of them as well. For Poland there are some very nice recently updated routes, which are distributed complete with trains and OR-timetables with plenty of DC traction in them (see: https://pkor.trainsim.pl).