ET25/Dragon: wheels slipping too eagerly

[Schyrsivochter]

The ET25 wheels tend to start slipping as soon as I go past ~300 kN. That’s 50 kN per axle, which is way below what modern electronically-controlled three-phase drives are generally capable of. Plus, Newag’s website itself says the Dragon’s starting tractive effort is, depending on configuration options, either 374 kN (62 kN per axle) or 450 kN (75 kN per axle).

I suspect that the wheel slip condition is calculated from total tractive effort and hard-coded for a four-axle locomotive, since 300 kN equals 75 kN per axle, which is generally about what any locomotive with 22.5 t axle load can do.

[Admin BOT]

Thank you for reporting this issue! Internal ticket number: #2397
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[Królik Uszasty]

Wheel-slip condition is calculated individually per axle, including current load on that axle - which changes with tractive effort generated by a vehicle. The "problem" is a result of static adhesion factor, which is assumed as 0.35. To obtain about 75 kN/axle we need to increase it to 0.40. However, it seems to be a bit high value. The solution will come with "adhesion manager", which will be change adhesion factor for vehicles basing on the weather.

[Schyrsivochter]

Thank you for your detailed answer! That’s interesting. Traxx always feels like it has better grip and I can push the kN/axle further up. But maybe that’s just a feeling and has no basis in actual simulator behaviour; I guess I’ll check this out next time I’m playing SimRail.