Merge pull request #520 from peternewell/brake-fix#4

Add checks for AirBrakeMaxMainResPipePressure.

Author: peternewell

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

@@ -1420,8 +1420,38 @@ public override void Initialize()
                 }
             }
 
-            if (MaximumMainReservoirPipePressurePSI == 0)
+            // MaximumMainReservoirPipePressurePSI is only used in twin pipe system, and should have a value
+            if ((BrakeSystem is AirTwinPipe))
             {
+
+                // for airtwinpipe system, make sure that a value is set for it
+                if (MaximumMainReservoirPipePressurePSI == 0)
+                {
+                    MaximumMainReservoirPipePressurePSI = MaxMainResPressurePSI;
+                    if (Simulator.Settings.VerboseConfigurationMessages)
+                    {
+                        Trace.TraceInformation("AirBrakeMaxMainResPipePressure not set in ENG file, set to default pressure of {0}.", FormatStrings.FormatPressure(MaximumMainReservoirPipePressurePSI, PressureUnit.PSI, MainPressureUnit, true));
+                    }
+
+                }
+            }
+            else if ((BrakeSystem is AirSinglePipe) && MaximumMainReservoirPipePressurePSI != 0)
+            {
+
+                // if value not equal to MaxMainResPressurePSI then reset (could already be at this value due to "copying" of locomotive)
+                if (MaximumMainReservoirPipePressurePSI != MaxMainResPressurePSI)
+                {
+                    // for a airsinglepipe system, AirBrakeMaxMainResPipePressure should be left out of ENG file, and it should be set the same as MaxMainResPressurePSI
+                    MaximumMainReservoirPipePressurePSI = MaxMainResPressurePSI;
+                    if (Simulator.Settings.VerboseConfigurationMessages)
+                    {
+                        Trace.TraceInformation("AirBrakeMaxMainResPipePressure is set in ENG file, but should not be normally used for AirSinglePipe system, reset to default pressure of {0}. Consider removing AirBrakeMaxMainResPipePressure parameter from ENG file", FormatStrings.FormatPressure(MaximumMainReservoirPipePressurePSI, PressureUnit.PSI, MainPressureUnit, true));
+                    }
+                }
+            }
+            else
+            {
+                // normal default setting. This should be the normal case for airsinglepipe systems
                 MaximumMainReservoirPipePressurePSI = MaxMainResPressurePSI;
             }
 
@@ -1440,7 +1470,7 @@ public override void Initialize()
                     {
                         Trace.TraceInformation("TrainBrakeController.MaxPressurePSI is assumed to be {0} Inhg, - confirmed as a value of {1} InHg", TempMaxPressure, Bar.ToInHg(Bar.FromPSI(TrainBrakeController.MaxPressurePSI)));
                     }
-                    
+
                 }
                 else if (TrainBrakeController.MaxPressurePSI < 7 || TrainBrakeController.MaxPressurePSI > 13) // Outside an acceptable range (Eqiv = 15InHg to 25InHg), then convert to a fixed default
                 {