Hello,
I would like to report what may be a fundamental issue in the traction physics model used by electric locomotives in SimRail.
The issue became noticeable while operating the TRAXX locomotive with a freight train of approximately 3000 tonnes, but I suspect it may affect the overall electric locomotive traction model rather than a single vehicle.
Observation:
In real electric locomotive operation, the highest traction current is typically drawn during startup and at low speeds, when maximum tractive effort is required. As speed increases, tractive effort decreases and traction current generally decreases as well.
In SimRail, I observe behaviour that appears to be reversed:
- Relatively low current at startup and low speeds.
- Current increases as speed increases.
- Wheel slip is more likely to occur at higher speeds rather than during startup and initial acceleration.
- Adhesion behaviour appears to be linked to this increasing current.
From an operational perspective, this feels unrealistic.
In real locomotive service, wheel slip is primarily a low-speed phenomenon because maximum tractive effort is developed during starting. Once the train gains speed, the risk of wheel slip generally decreases significantly.
In SimRail, the opposite seems to occur. This creates a situation where the locomotive can appear more prone to wheel slip at higher speeds than during starting, which does not correspond to real-world locomotive behaviour.
Because the observed behaviour involves both traction current and wheel slip characteristics, I believe the issue may originate from the underlying traction and adhesion calculation rather than from a single locomotive implementation.
I have experience with real electric locomotive operation, which is why this difference became particularly noticeable during heavy freight runs.
Could the development team please verify whether the relationship between traction current, tractive effort, speed and adhesion is functioning as intended?
Thank you for your time and for the continued development of SimRail.
