Add documentation

Author: cesarBLG

Source/Documentation/Manual/features-rollingstock.rst

@@ -2087,8 +2087,15 @@ or::
       ORTSEngineBrakeController ( "YourBrakes.cs" )
   )
 
-The .cs extension is optional. "MSTS" loads the default MSTS-compatible 
-implementation, so do `not` use this name for your own script.
+The .cs extension is optional. Alternatively, there are several built-in
+brake controllers:
+- "MSTS": default implementation for a notched brake controller. Each notch
+  behaves as defined in the :ref:`Train Brake Controller Positions <physics-brake-controller>` section.
+- "PBL2": a brake controller widely used in Europe. It has a stable Hold position which keeps brake
+  pipe pressure, and two unstable positions that apply or release the brakes when pressed. The controller
+  also generates the electrical Release and Apply signals required for the UIC EP brake.
+
+Do `not` use these names for your own script.
 
 .. _features-scripting-cb:
 

Source/Orts.Simulation/Simulation/RollingStocks/SubSystems/Controllers/PBL2BrakeController.cs

@@ -53,7 +53,6 @@ public enum ControllerPosition
         private Timer ResetTimer { get; set; }
 
         // brake controller values
-        private float FirstDepressureBar = 0.5f;
         private float BrakeReleasedDepressureBar = 0.2f;
         private float EpActivationThresholdBar = 0.15f;
 
@@ -151,9 +150,9 @@ public override void UpdatePressure(ref float pressureBar, float elapsedClockSec
                 return;
             }
 
-            if (!FirstDepression && CurrentPosition == ControllerPosition.Apply && pressureBar > Math.Max(MaxPressureBar() - FirstDepressureBar, 0))
+            if (!FirstDepression && CurrentPosition == ControllerPosition.Apply && pressureBar > Math.Max(MaxPressureBar() - MinReductionBar(), 0))
                 FirstDepression = true;
-            else if (FirstDepression && pressureBar <= Math.Max(MaxPressureBar() - FirstDepressureBar, 0))
+            else if (FirstDepression && pressureBar <= Math.Max(MaxPressureBar() - MinReductionBar(), 0))
                 FirstDepression = false;
 
             if (QuickReleaseButtonPressed())
@@ -179,7 +178,7 @@ public override void UpdatePressure(ref float pressureBar, float elapsedClockSec
                 CurrentState = State.Apply;
             else if (
                 CurrentPosition == ControllerPosition.Apply && pressureBar > MaxPressureBar() - FullServReductionBar()
-                || FirstDepression && CurrentPosition != ControllerPosition.Release && !QuickRelease && pressureBar > MaxPressureBar() - FirstDepressureBar
+                || FirstDepression && CurrentPosition != ControllerPosition.Release && !QuickRelease && pressureBar > MaxPressureBar() - MinReductionBar()
                 )
                 CurrentState = State.Apply;
             else if (OverchargeElimination && pressureBar > MaxPressureBar())
@@ -199,7 +198,6 @@ public override void UpdatePressure(ref float pressureBar, float elapsedClockSec
             else
                 CurrentState = State.Hold;
 
-            float targetPressureBar = pressureBar;
             switch (CurrentState)
             {
                 case State.Overcharge:
@@ -286,6 +284,9 @@ public override void UpdatePressure(ref float pressureBar, float elapsedClockSec
 
             if (QuickRelease && pressureBar >= Math.Min(MaxPressureBar(), MainReservoirPressureBar()))
                 QuickRelease = false;
+
+            if (OverchargeElimination && pressureBar <= MaxPressureBar())
+                OverchargeElimination = false;
         }
 
         public override void UpdateEngineBrakePressure(ref float pressureBar, float elapsedClockSeconds)