Fix bugs introduced during post-review changes

Author: cesarBLG

Source/Documentation/Manual/physics.rst

@@ -425,6 +425,7 @@ locomotive (regardless of transmission type) are as follows:
    single: MaxPower
    single: MaxForce
    single: MaxContinuousForce
+   single: ORTSTractiveForceIsPowerLimited
 
 ``ORTSDieselEngineMaxPower`` ==> sets the maximum power output at the 
 shaft of the diesel engine (or prime mover).
@@ -438,6 +439,9 @@ wheels when starting.
 continuously supply to the wheels without exceeding the design specifications. 
 Typically this is linked to a particular speed (see next parameter).
 
+``ORTSTractiveForceIsPowerLimited`` ==> determines if tractive force curves
+shall be limited to the available output power from the diesel engine.
+
 .. index::
    single: ORTSSpeedOfMaxContinuousForce
    single: MaxVelocity

Source/Orts.Simulation/Simulation/RollingStocks/MSTSDieselLocomotive.cs

@@ -90,6 +90,7 @@ public float DieselLevelL
         float InitialMassKg = 100000.0f;
 
         public float LocomotiveMaxRailOutputPowerW;
+        public bool TractiveForcePowerLimited = false;
 
         public float EngineRPM;
         public SmoothedData ExhaustParticles = new SmoothedData(1);
@@ -170,6 +171,8 @@ public override void Parse(string lowercasetoken, STFReader stf)
                 case "engine(dieselsmokeeffectmaxsmokerate": MaxExhaust = stf.ReadFloatBlock(STFReader.UNITS.None, null); break;
                 case "engine(dieselsmokeeffectmaxmagnitude": MaxMagnitude = stf.ReadFloatBlock(STFReader.UNITS.None, null); break;
 
+                case "engine(ortstractiveforceispowerlimited": TractiveForcePowerLimited = stf.ReadBoolBlock(false); break;
+
                 case "engine(ortsdieseltransmissiontype":
                     stf.MustMatch("(");
                     var transmissionType = stf.ReadString();
@@ -437,6 +440,8 @@ public override void Copy(MSTSWagon copy)
             EngineRPMderivation = locoCopy.EngineRPMderivation;
             EngineRPMold = locoCopy.EngineRPMold;
 
+            TractiveForcePowerLimited = locoCopy.TractiveForcePowerLimited;
+
             MaxDieselLevelL = locoCopy.MaxDieselLevelL;
             DieselUsedPerHourAtMaxPowerL = locoCopy.DieselUsedPerHourAtMaxPowerL;
             DieselUsedPerHourAtIdleL = locoCopy.DieselUsedPerHourAtIdleL;

Source/Orts.Simulation/Simulation/RollingStocks/MSTSLocomotive.cs

@@ -2526,6 +2526,7 @@ public void UpdateForceWithRamp(ref float forceN, float elapsedClockSeconds, flo
         {
             if (targetForceN > maxForceN) targetForceN = maxForceN;
             if (forceN > maxForceN) forceN = maxForceN;
+            bool toZero = targetForceN == 0;
             if (AbsTractionSpeedMpS > 0)
             {
                 float powerW = forceN * PrevAbsTractionSpeedMpS;
@@ -2539,23 +2540,25 @@ public void UpdateForceWithRamp(ref float forceN, float elapsedClockSeconds, flo
                         targetForceN = Math.Min(targetForceN, targetPowerW / AbsTractionSpeedMpS);
                     }
                 }
-                if (targetPowerW < powerW && (targetPowerW == 0 ? rampZeroWpS : rampDownWpS) > 0)
+                if (targetPowerW < powerW && (toZero ? rampZeroWpS : rampDownWpS) > 0)
                 {
-                    float maxChangeW = (targetPowerW == 0 ? rampZeroWpS : rampDownWpS) * elapsedClockSeconds;
+                    float maxChangeW = (toZero ? rampZeroWpS : rampDownWpS) * elapsedClockSeconds;
                     if (powerW - maxChangeW > targetPowerW)
                     {
                         targetPowerW = powerW - maxChangeW;
                         targetForceN = Math.Max(targetForceN, Math.Min(forceN, targetPowerW / AbsTractionSpeedMpS));
                     }
                 }
             }
-            if (targetForceN > forceN && rampUpNpS > 0)
+            if (targetForceN > forceN)
             {
-                forceN = Math.Min(targetForceN, forceN + rampUpNpS * elapsedClockSeconds);
+                if (rampUpNpS > 0) forceN = Math.Min(forceN + rampUpNpS * elapsedClockSeconds, targetForceN);
+                else forceN = targetForceN;
             }
-            else if (targetForceN < forceN && (targetForceN == 0 ? rampZeroNpS : rampDownNpS) > 0)
+            else if (targetForceN < forceN)
             {
-                forceN = Math.Max(targetForceN, forceN - (targetForceN == 0 ? rampZeroNpS : rampDownNpS) * elapsedClockSeconds);
+                if ((toZero ? rampZeroNpS : rampDownNpS) > 0) forceN = Math.Max(forceN - (toZero ? rampZeroNpS : rampDownNpS) * elapsedClockSeconds, targetForceN);
+                else forceN = targetForceN;
             }
         }
         /// <summary>
@@ -2611,7 +2614,7 @@ protected virtual void UpdateTractionForce(float elapsedClockSeconds)
             // Ensure that throttle never exceeds the limits imposed by other subsystems
             float maxthrottle = MaxThrottlePercent / 100;
             // For diesel locomotives, also take into account the throttle setting associated to the current engine RPM
-            if (IsPlayerTrain && this is MSTSDieselLocomotive diesel) maxthrottle = Math.Min(maxthrottle, diesel.DieselEngines.ApparentThrottleSetting / 100.0f);
+            if (IsPlayerTrain && this is MSTSDieselLocomotive diesel && !diesel.TractiveForcePowerLimited) maxthrottle = Math.Min(maxthrottle, diesel.DieselEngines.ApparentThrottleSetting / 100.0f);
             if (t > maxthrottle) t = maxthrottle;
             t = MathHelper.Clamp(t, 0, 1);
 

Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/PowerSupplies/DieselPowerSupply.cs

@@ -259,7 +259,8 @@ public override void Update(float elapsedClockSeconds)
                 DieselEngineMinRpm = 0;
             }
 
-            AvailableTractionPowerW = Math.Max(DieselEngineOutputPowerW - ElectricTrainSupplyPowerW, 0);
+            if (DieselLocomotive.TractiveForcePowerLimited)
+                AvailableTractionPowerW = Math.Max(DieselEngineOutputPowerW - ElectricTrainSupplyPowerW, 0);
 
             UpdateSounds();
         }