Update calculation of Operative Brakes and Tons per Operative Brake.

Brake Force alone is not sufficient to determine if the car has
operative brakes. BrakeValve (BrakeEquipmentType) does not work well for
the Content Manager, and even some newer rollingstock has it incorrect.
Thus BrakeSystem (BrakeSystemType) not being "just a pipe" or manual
braking seems to work best.

Also corrected TpOP to only use trailing tonnage (as defined by BNSF).

Author: rwf-rr

Source/RunActivity/Viewer3D/Popups/HelpWindow.cs

@@ -37,6 +37,7 @@
 using SharpFont;
 using static Orts.Viewer3D.WebServices.TrainCarOperationsWebpage.OperationsSend;
 using SharpDX.Direct3D9;
+using Orts.Simulation.RollingStocks.SubSystems.Brakes.MSTS;
 
 namespace Orts.Viewer3D.Popups
 {
@@ -1209,7 +1210,7 @@ private void AddAggregatedTrainInfo(Train playerTrain, ControlLayout scrollbox,
             float engMaxContTractiveForceN = 0f; float engMaxDynBrakeForceN = 0f; string forceSeparator = "";  // when set, indicates that subsequent engines are in a separate block
 
             float wagMassKg = 0f; string massSeparator = ""; // when set, indicates that subsequent engines are in a separate block
-            int numOperativeBrakes = 0;
+            float trailingMassKg = 0f; int numOperativeBrakes = 0;
             bool isMetric = false; bool isUK = false;  // isImperial* does not seem to be used in simulation
 
             if (TrainInfoSpriteSheet == null) { TrainInfoSpriteSheet = SharedTextureManager.Get(Owner.Viewer.RenderProcess.GraphicsDevice, Path.Combine(Owner.Viewer.ContentPath, "TrainInfoSprites.png")); }
@@ -1250,6 +1251,8 @@ private void AddAggregatedTrainInfo(Train playerTrain, ControlLayout scrollbox,
                     numCars++;
                     numAxles += wag.GetWagonNumAxles();
                     wagMassKg += wag.MassKG;
+                    trailingMassKg += wag.MassKG;
+                    if (wag.MaxBrakeForceN > 0 && car.BrakeSystem != null && !(car.BrakeSystem is SingleTransferPipe) && !(car.BrakeSystem is ManualBraking)) { numOperativeBrakes++; }
 
                     // handle transition from engines to wagons
                     if (engCount > 0 || (engCount == 0 && numCars == 0))
@@ -1270,7 +1273,6 @@ private void AddAggregatedTrainInfo(Train playerTrain, ControlLayout scrollbox,
                     if (couplerStrength < lowestCouplerStrengthN) { lowestCouplerStrengthN = couplerStrength; }
                     var derailForce = GetDerailForce(wag);
                     if (derailForce < lowestDerailForceN) { lowestDerailForceN = derailForce; }
-                    if (wag.MaxBrakeForceN > 0) { numOperativeBrakes++; }  // simplistic: real world has cutout brakes, and no brakes on some articulated car-segments
 
                     carInfoList.Add(new CarInfo(wag.MassKG, isEng));
                 }
@@ -1328,7 +1330,7 @@ private void AddAggregatedTrainInfo(Train playerTrain, ControlLayout scrollbox,
                 line.Add(new Label(labelWidth, line.RemainingHeight, Viewer.Catalog.GetString("Horespower per Ton:"), LabelAlignment.Left));
                 line.Add(new Label(line.RemainingWidth, line.RemainingHeight, string.Format("{0:0.0}", hpt), LabelAlignment.Left));
 
-                float tpob = numOperativeBrakes > 0 ? Kg.ToTUS(totMassKg) / numOperativeBrakes : 0;
+                float tpob = numOperativeBrakes > 0 ? Kg.ToTUS(trailingMassKg) / numOperativeBrakes : 0;
                 line = scrollbox.AddLayoutHorizontalLineOfText();
                 line.Add(new Label(labelWidth, line.RemainingHeight, Viewer.Catalog.GetString("Tons per Operative Brake:"), LabelAlignment.Left));
                 line.Add(new Label(line.RemainingWidth, line.RemainingHeight, string.Format("{0:0}", tpob), LabelAlignment.Left));