Automatic merge of T1.6-rc4-34-g041d7ab18 and 16 pull requests

- Pull request #1086 at e10390b: Add Settings Exporter tool (copy settings to INI, etc)
- Pull request #1091 at aa72c13: Automatic speed control
- Pull request #1104 at 86d38a2: Handle simple adhesion within the axle module
- Pull request #1110 at 387388e: Fix Activity Runner persists after loading exception
- Pull request #1115 at 270f22f: Do not activate ETS switch if no suitable cars are attached
- Pull request #1120 at ba3c47f: Automatically Calculate Friction Values if Missing
- Pull request #1121 at 91d2d26: Manually Override Articulation
- Pull request #1130 at abe7c8a: Fix F9 points to an incorrect car ID.
- Pull request #1132 at 934d29e: Fixes For Correct Questionable Braking Parameters
- Pull request #1133 at 8dc00d5: Minor Fix for Brake Pipe Charging
- Pull request #1136 at 6f1b82f: Fix Curve Resistance Calculation
- Pull request #1137 at c2c9e2a: Apply brakes at startup on minimal reduction
- Pull request #1082 at 5845a1a: Allow variable water level in glass gauge
- Pull request #1081 at 689494b: Brake cuts power unification
- Pull request #1124 at fab5457: Built-in PBL2 brake controller
- Pull request #1128 at 58de4c3: Particle Emitter Overhaul

Author: openrails-bot

Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/PowerTransmissions/Axle.cs

@@ -1305,6 +1305,9 @@ void Integrate(float elapsedClockSeconds)
         /// <param name="elapsedSeconds"></param>
         public virtual void Update(float elapsedSeconds)
         {
+            if (float.IsNaN(TrainSpeedMpS)) TrainSpeedMpS = 0;
+            if (double.IsNaN(AxleSpeedMpS)) AxleSpeedMpS = 0;
+
             bool advancedAdhesion = Car is MSTSLocomotive locomotive && locomotive.AdvancedAdhesionModel;
             advancedAdhesion &= DriveType != AxleDriveType.NotDriven; // Skip integrator for undriven axles to save CPU
             forceToAccelerationFactor = WheelRadiusM * WheelRadiusM / totalInertiaKgm2;