Add emergency dump valve

Author: cesarBLG

Source/Documentation/Manual/physics.rst

@@ -2944,6 +2944,7 @@ MaxAuxilaryChargingRate and EmergencyResChargingRate.
 .. index::
    single: BrakePipeVolume
    single: ORTSEmergencyValveActuationRate
+   single: ORTSEmergencyDumpValveRate
    single: ORTSMainResPipeAuxResCharging
    single: ORTSMainResChargingRate
    single: ORTSEngineBrakeReleaseRate
@@ -2972,6 +2973,8 @@ MaxAuxilaryChargingRate and EmergencyResChargingRate.
   brake actuation of the triple valve. If the pressure in the brake pipe
   decreases at a higher rate than specified, the triple valve will switch to
   emergency mode.
+- ``Wagon(ORTSEmergencyDumpValveRate)``-- Rate at which BP is locally discharged
+  at every wagon during an emergency brake application.
 - ``Wagon(ORTSMainResPipeAuxResCharging`` -- Boolean value that indicates,
   for twin pipe systems, if the main reservoir pipe is used for charging the auxiliary
   reservoirs. If set to false, the main reservoir pipe will not be used

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

@@ -51,6 +51,7 @@ public class AirSinglePipe : MSTSBrakeSystem
         protected float MaxAuxilaryChargingRatePSIpS = 1.684f;
         protected float BrakeInsensitivityPSIpS = 0.07f;
         protected float EmergencyValveActuationRatePSIpS = 0;
+        protected float EmergencyDumpValveRatePSIpS = 0;
         protected float EmergResChargingRatePSIpS = 1.684f;
         protected float EmergAuxVolumeRatio = 1.4f;
         protected string DebugType = string.Empty;
@@ -116,6 +117,7 @@ public override void InitializeFromCopy(BrakeSystem copy)
             MaxAuxilaryChargingRatePSIpS = thiscopy.MaxAuxilaryChargingRatePSIpS;
             BrakeInsensitivityPSIpS = thiscopy.BrakeInsensitivityPSIpS;
             EmergencyValveActuationRatePSIpS = thiscopy.EmergencyValveActuationRatePSIpS;
+            EmergencyDumpValveRatePSIpS = thiscopy.EmergencyDumpValveRatePSIpS;
             EmergResChargingRatePSIpS = thiscopy.EmergResChargingRatePSIpS;
             EmergAuxVolumeRatio = thiscopy.EmergAuxVolumeRatio;
             TwoPipes = thiscopy.TwoPipes;
@@ -232,6 +234,7 @@ public override void Parse(string lowercasetoken, STFReader stf)
                 case "wagon(brakepipevolume": BrakePipeVolumeM3 = Me3.FromFt3(stf.ReadFloatBlock(STFReader.UNITS.VolumeDefaultFT3, null)); break;
                 case "wagon(ortsbrakeinsensitivity": BrakeInsensitivityPSIpS = stf.ReadFloatBlock(STFReader.UNITS.PressureRateDefaultPSIpS, 0.07f); break;
                 case "wagon(ortsemergencyvalveactuationrate": EmergencyValveActuationRatePSIpS = stf.ReadFloatBlock(STFReader.UNITS.PressureRateDefaultPSIpS, 15f); break;
+                case "wagon(ortsemergencydumpvalverate": EmergencyDumpValveRatePSIpS = stf.ReadFloatBlock(STFReader.UNITS.PressureRateDefaultPSIpS, 15f); break;
                 case "wagon(ortsmainrespipeauxrescharging": MRPAuxResCharging = this is AirTwinPipe && stf.ReadBoolBlock(true); break;
             }
         }
@@ -307,7 +310,10 @@ public override void Initialize(bool handbrakeOn, float maxPressurePSI, float fu
             CylPressurePSI = AutoCylPressurePSI = immediateRelease ? 0 : Math.Min((maxPressurePSI - BrakeLine1PressurePSI) * AuxCylVolumeRatio, MaxCylPressurePSI);
             AuxResPressurePSI = Math.Max(TwoPipes ? maxPressurePSI : maxPressurePSI - AutoCylPressurePSI / AuxCylVolumeRatio, BrakeLine1PressurePSI);
             if ((Car as MSTSWagon).EmergencyReservoirPresent)
+            {
                 EmergResPressurePSI = Math.Max(AuxResPressurePSI, maxPressurePSI);
+                if (EmergencyValveActuationRatePSIpS == 0) EmergencyValveActuationRatePSIpS = 15;
+            }
             TripleValveState = AutoCylPressurePSI < 1 ? ValveState.Release : ValveState.Lap;
             HoldingValve = ValveState.Release;
             HandbrakePercent = handbrakeOn & (Car as MSTSWagon).HandBrakePresent ? 100 : 0;
@@ -440,6 +446,12 @@ public override void Update(float elapsedClockSeconds)
                         EmergResPressurePSI -= dp;
                         AuxResPressurePSI += dp * EmergAuxVolumeRatio;
                     }
+                    if (EmergencyDumpValveRatePSIpS > 0)
+                    {
+                        BrakeLine1PressurePSI -= elapsedClockSeconds * EmergencyDumpValveRatePSIpS;
+                        if (BrakeLine1PressurePSI < 0)
+                            BrakeLine1PressurePSI = 0;
+                    }
                 }
             }