Automatic merge of T1.5.1-411-g51d4cd969 and 19 pull requests

- Pull request #570 at de7a14f: Experimental glTF 2.0 support with PBR lighting
- Pull request #757 at d9d75f4: Unify RailDriver code implementations
- Pull request #799 at dc03850: Consolidated wind simulation
- Pull request #802 at 4d198e4: Added support for activity location events to the TrackViewer
- Pull request #803 at 7157e08: Various adjustments to steam adhesion
- Pull request #813 at 7fdad38: Refactored garbage generators
- Pull request #815 at a5cc165: chore: Add GitHub automatic release notes configuration
- Pull request #818 at 0d2162a: Allow independent drive axles for locomotives
- Pull request #821 at e0fa5a8: Adds suppression of safety valves
- Pull request #823 at 5e1c03b: Select track sound volume percent retained in .eng and .wag files
- Pull request #824 at f16ebed: Update Readme.md
- Pull request #825 at 29ed427: 2D Cabview controls for side viewpoints https://blueprints.launchpad.net/or/+spec/2dcabview-controls-for-side-views
- Pull request #829 at 434af02: Improvements for air brakes #3 - Emergency valves
- Pull request #830 at 280ee74: Electric locomotive hot start
- Pull request #831 at c8927a4: preliminary version switchpanel on tablet
- Pull request #832 at bb8941f: Fix Cruise Control together with Train Brake
- Pull request #833 at 01aaca7: Implement brake relay valve
- Pull request #834 at 7a98eca: Replaces email service with FormSpark
- Pull request #835 at 8b4e134: Correct Brake Shoe Force Calculation

Author: openrails-bot

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

@@ -87,7 +87,6 @@ public class MSTSWagon : TrainCar
         public bool GenericItem1;
         public bool GenericItem2;
 
-        Interpolator BrakeShoeFrictionFactor;  // Factor of friction for wagon brake shoes
         const float WaterLBpUKG = 10.0f;    // lbs of water in 1 gal (uk)
         float TempMassDiffRatio;
 
@@ -597,8 +596,9 @@ public virtual void LoadFromWagFile(string wagFilePath)
 
             // Initialise key wagon parameters
             MassKG = InitialMassKG;
+
             MaxHandbrakeForceN = InitialMaxHandbrakeForceN;
-            if (MaxBrakeShoeForceN != 0)
+            if (MaxBrakeShoeForceN != 0 && BrakeShoeFrictionFactor != null)
             {
                 MaxBrakeForceN = MaxBrakeShoeForceN;
             }

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

@@ -139,6 +139,8 @@ public abstract class TrainCar
            0.0f, 31.0f
         };
 
+        public Interpolator BrakeShoeFrictionFactor;  // Factor of friction for wagon brake shoes
+
         public static Interpolator SteamHeatBoilerWaterUsageGalukpH()
         {
             return new Interpolator(SteamUsageLbpH, WaterUsageGalukpH);
@@ -968,7 +970,7 @@ public virtual void UpdateBrakeSlideCalculation()
                 //For a user defined case the base value is the zero speed value from the curve entered by the user.
                 // For a "default" case where no user data has been added to the WAG file, the base friction value has been assumed to be 0.2, thus maximum value of 20% applied.
 
-                if (UserFriction != 0 && MaxBrakeShoeForceN != 0) // Assume user has set up brakeshoe force and brakeshoe CoF
+                if (BrakeShoeFrictionFactor != null && MaxBrakeShoeForceN != 0) // Assume user has set up brakeshoe force and brakeshoe CoF
                 {
                     BrakeShoeCoefficientFrictionAdjFactor = UserFriction * AdhesionMultiplier;
                     BrakeShoeRetardCoefficientFrictionAdjFactor = BrakeShoeCoefficientFrictionAdjFactor;