First phase of wheel slide protection

Author: peternewell

Source/Orts.Simulation/Simulation/RollingStocks/MSTSWagon.cs

@@ -1018,6 +1018,18 @@ public virtual void Parse(string lowercasetoken, STFReader stf)
                 case "wagon(ortsbrakeshoefriction": BrakeShoeFrictionFactor = new Interpolator(stf); break;
                 case "wagon(maxhandbrakeforce": InitialMaxHandbrakeForceN = stf.ReadFloatBlock(STFReader.UNITS.Force, null); break;
                 case "wagon(maxbrakeforce": InitialMaxBrakeForceN = stf.ReadFloatBlock(STFReader.UNITS.Force, null); break;
+                case "wagon(ortswheelbrakeslipprotection":
+                  // stf.MustMatch("(");
+                    var brakeslipprotection = stf.ReadFloatBlock(STFReader.UNITS.None, null);
+                    if (brakeslipprotection == 1)
+                    {
+                        WheelBrakeSlipProtectionFitted = true;
+                    }
+                    else
+                    {
+                        WheelBrakeSlipProtectionFitted = false;
+                    }
+                    break;
                 case "wagon(ortsdavis_a": DavisAN = stf.ReadFloatBlock(STFReader.UNITS.Force, null); break;
                 case "wagon(ortsdavis_b": DavisBNSpM = stf.ReadFloatBlock(STFReader.UNITS.Resistance, null); break;
                 case "wagon(ortsdavis_c": DavisCNSSpMM = stf.ReadFloatBlock(STFReader.UNITS.ResistanceDavisC, null); break;
@@ -1341,6 +1353,7 @@ public virtual void Copy(MSTSWagon copy)
             DriverWheelRadiusM = copy.DriverWheelRadiusM;
             MainSoundFileName = copy.MainSoundFileName;
             BrakeShoeFrictionFactor = copy.BrakeShoeFrictionFactor;
+            WheelBrakeSlipProtectionFitted = copy.WheelBrakeSlipProtectionFitted;
             InitialMaxBrakeForceN = copy.InitialMaxBrakeForceN;
             InitialMaxHandbrakeForceN = copy.InitialMaxHandbrakeForceN;
             MaxBrakeForceN = copy.MaxBrakeForceN;

Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/Brakes/MSTS/AirSinglePipe.cs

@@ -377,7 +377,7 @@ public override void Update(float elapsedClockSeconds)
                 UpdateTripleValveState(threshold);
 
             // triple valve is set to charge the brake cylinder
-            if (TripleValveState == ValveState.Apply || TripleValveState == ValveState.Emergency)
+            if ((TripleValveState == ValveState.Apply || TripleValveState == ValveState.Emergency) && !Car.WheelBrakeSlipProtectionActive)
             {
                 float dp = elapsedClockSeconds * MaxApplicationRatePSIpS;
                 if (AuxResPressurePSI - dp / AuxCylVolumeRatio < AutoCylPressurePSI + dp)
@@ -487,6 +487,42 @@ public override void Update(float elapsedClockSeconds)
             else
                 CylPressurePSI = AutoCylPressurePSI;
 
+            // During braking wheelslide control is effected throughout the train by additional equipment on each vehicle. In the piping to each pair of brake cylinders are fitted electrically operated 
+            // dump valves. When axle rotations which are sensed electrically, differ by a predetermined speed the dump valves are operated releasing brake cylinder pressure to both axles of the affected 
+            // bogie.
+
+            // Dump valve operation will cease when differences in axle rotations arewithin specified limits or the axle accelerates faster than a specified rate. The dump valve will only operate for a
+            // maximum period of seven seconds after which time it will be de-energised and the dump valve will not re-operate until the train has stopped or the throttle operated.
+
+            // Dump valve operation is prevented under the following conditions:-
+            // (i) When the Power Controller is open.
+
+            // (ii) When Brake Pipe Pressure has been reduced below 250 kPa (36.25psi). 
+
+            if (Car.WheelBrakeSlipProtectionFitted)
+            {
+                if ((Car.BrakeSkidWarning || Car.BrakeSkid) && BrakeLine1PressurePSI > 36.25)
+                {
+                    Car.WheelBrakeSlipProtectionActive = true;
+//                    Trace.TraceInformation("WSP#1 - CarID {0} BC {1} Auto {2} BP1 {3}", Car.CarID, CylPressurePSI, AutoCylPressurePSI, BrakeLine1PressurePSI);
+                    AutoCylPressurePSI -= elapsedClockSeconds * MaxReleaseRatePSIpS;
+                    CylPressurePSI = AutoCylPressurePSI;
+//                    Trace.TraceInformation("WSP#2 - CarID {0} BC {1} Auto {2}", Car.CarID, CylPressurePSI, AutoCylPressurePSI);
+                }
+                else
+                {
+                    Car.WheelBrakeSlipProtectionActive = false;
+//                    Trace.TraceInformation("WSP Non-active - CarID {0} BC {1} Auto {2} BP1 {3}", Car.CarID, CylPressurePSI, AutoCylPressurePSI, BrakeLine1PressurePSI);
+                }
+
+
+
+
+
+            }
+
+
+
             // Record HUD display values for brake cylinders depending upon whether they are wagons or locomotives/tenders (which are subject to their own engine brakes)   
             if (Car.WagonType == MSTSWagon.WagonTypes.Engine || Car.WagonType == MSTSWagon.WagonTypes.Tender)
             {

Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/Brakes/MSTS/EPBrakeSystem.cs

@@ -49,7 +49,7 @@ public override void Update(float elapsedClockSeconds)
 
             base.Update(elapsedClockSeconds);
 
-            if (AutoCylPressurePSI < demandedAutoCylPressurePSI)
+            if (AutoCylPressurePSI < demandedAutoCylPressurePSI && !Car.WheelBrakeSlipProtectionActive)
             {
                 float dp = elapsedClockSeconds * MaxApplicationRatePSIpS;
                 if (BrakeLine2PressurePSI - dp * AuxBrakeLineVolumeRatio / AuxCylVolumeRatio < AutoCylPressurePSI + dp)

Source/Orts.Simulation/Simulation/RollingStocks/TrainCar.cs

@@ -256,7 +256,10 @@ public float ConvectionFactor
         }
 
         // Used to calculate wheel sliding for locked brake
+        public bool WheelBrakeSlipProtectionFitted = false;
+        public bool WheelBrakeSlipProtectionActive = false;
         public bool BrakeSkid = false;
+        public bool BrakeSkidWarning = false;
         public bool HUDBrakeSkid = false;
         public float BrakeShoeCoefficientFriction = 1.0f; // Brake Shoe coefficient - for simple adhesion model set to 1
         public float BrakeShoeCoefficientFrictionAdjFactor = 1.0f; // Factor to adjust Brake force by - based upon changing friction coefficient with speed, will change when wheel goes into skid
@@ -922,7 +925,17 @@ public virtual void UpdateBrakeSlideCalculation()
 
                 if (this is MSTSDieselLocomotive || this is MSTSElectricLocomotive)
                 {
-                   if (WheelSlip && ThrottlePercent < 0.1f && BrakeRetardForceN > 25.0) // If advanced adhesion model indicates wheel slip, then check other conditiond (throttle and brake force) to determine whether it is a wheel slip or brake skid
+
+                    if (WheelSlipWarning && ThrottlePercent < 0.1f && BrakeRetardForceN > 25.0) // If advanced adhesion model indicates wheel slip, then check other conditiond (throttle and brake force) to determine whether it is a wheel slip or brake skid
+                    {
+                        BrakeSkidWarning = true;  // set brake skid flag true
+                    }
+                    else
+                    {
+                        BrakeSkidWarning = false;
+                    }
+
+                    if (WheelSlip && ThrottlePercent < 0.1f && BrakeRetardForceN > 25.0) // If advanced adhesion model indicates wheel slip, then check other conditiond (throttle and brake force) to determine whether it is a wheel slip or brake skid
                     {
                        BrakeSkid = true;  // set brake skid flag true
                     } 
@@ -938,6 +951,20 @@ public virtual void UpdateBrakeSlideCalculation()
                     // Calculate tread force on wheel - use the retard force as this is related to brakeshoe coefficient, and doesn't vary with skid.
                     BrakeWheelTreadForceN = BrakeRetardForceN;
 
+                    if (!BrakeSkidWarning && AbsSpeedMpS > 0.01)
+                    {
+                        var wagonbrakeadhesiveforcen = MassKG * GravitationalAccelerationMpS2 * Train.WagonCoefficientFriction; // Adhesive force wheel normal 
+
+                        if (BrakeWheelTreadForceN > 0.80f * WagonBrakeAdhesiveForceN)
+                        {
+                            BrakeSkidWarning = true; 	// wagon wheel is about to slip
+                        }
+                    }
+                    else if ( BrakeWheelTreadForceN < 0.75f * WagonBrakeAdhesiveForceN)
+                    {
+                        BrakeSkidWarning = false; 	// wagon wheel is back to normal
+                    }
+
 
                     // Calculate adhesive force based upon whether in skid or not
                     if (BrakeSkid)
@@ -948,6 +975,7 @@ public virtual void UpdateBrakeSlideCalculation()
                     {
                         WagonBrakeAdhesiveForceN = MassKG * GravitationalAccelerationMpS2 * Train.WagonCoefficientFriction; // Adhesive force wheel normal
                     }
+                                   
 
                     // Test if wheel forces are high enough to induce a slip. Set slip flag if slip occuring 
                     if (!BrakeSkid && AbsSpeedMpS > 0.01)  // Train must be moving forward to experience skid