More documentation, and adjust smoke stack with exhaust.

Author: peternewell

Source/Documentation/Manual/physics.rst

@@ -339,6 +339,16 @@ The ``ORTSSlipControlSystem ( Full )``  parameter can be inserted
 into the engine section of the .eng file to indicate the presence of
 such system.
 
+Steam locomotives will have varying magnitude of rotational forces depending upon the separation 
+between the cylinder crank angles.
+
+The crank angles for example of a 2 cylinder locomotive has a 90 deg separation whereas a 3 cylinder locomotive 
+has a 120 deg variation. OR will default to a "common" value for the number of cylinders defined, but the user 
+can override this with "ORTSWheelCrankAngleDifference ( A B C D )", where A, B, C and D are the separations for 
+up to a 4 cylinder locomotive. For example, a 4 cylinder locomotive can have a separation of 90 deg for each 
+cylinder or sometimes it has two of the cranks separated by 45 deg instead. These values can either be in 
+Rad (default) or Deg.
+
 
 Engine -- Classes of Motive Power
 =================================

Source/Orts.Simulation/Simulation/RollingStocks/MSTSSteamLocomotive.cs

@@ -710,6 +710,7 @@ public float TenderCoalMassKG              // Decreased by firing and increased
         bool CylinderCock42On = false;
         public bool Cylinder2SteamEffects = false;
         public bool CylinderAdvancedSteamEffects = false;
+        public bool CylinderAdvancedSteamExhaustEffects = false;
         public bool GeneratorSteamEffects = false;
         public float CompressorParticleDurationS = 3.0f;
         public float Cylinder1ParticleDurationS = 3.0f;
@@ -2468,8 +2469,28 @@ private void UpdateFX(float elapsedClockSeconds)
             float SmokeColorFireMass = (FireMassKG / IdealFireMassKG); // As firemass exceeds the ideal mass the fire becomes 'blocked', when firemass is < ideal then fire burns more freely.
             SmokeColorFireMass = (1.0f / SmokeColorFireMass) * (1.0f / SmokeColorFireMass) * (1.0f / SmokeColorFireMass); // Inverse the firemass value, then cube it to make it a bit more significant
 
-            StackSteamVelocityMpS.Update(elapsedClockSeconds, (float)Math.Sqrt(KPa.FromPSI(Pressure_c_AtmPSI) * 1000 * 2 / WaterDensityAt100DegC1BarKGpM3));
-            StackSteamVolumeM3pS = Kg.FromLb(CylinderSteamUsageLBpS + BlowerSteamUsageLBpS + RadiationSteamLossLBpS + CompSteamUsageLBpS + GeneratorSteamUsageLBpS) * SteamVaporSpecVolumeAt100DegC1BarM3pKG;
+            if (CylinderAdvancedSteamExhaustEffects)
+            {
+
+                if (CylinderSteamExhaust1On || CylinderSteamExhaust2On || CylinderSteamExhaust3On || CylinderSteamExhaust4On)
+                {
+                    StackSteamVelocityMpS.Update(elapsedClockSeconds, (float)Math.Sqrt(KPa.FromPSI(Pressure_c_AtmPSI) * 1000 * 50 / WaterDensityAt100DegC1BarKGpM3));
+                    StackSteamVolumeM3pS = Kg.FromLb(CylinderSteamUsageLBpS + BlowerSteamUsageLBpS + RadiationSteamLossLBpS + CompSteamUsageLBpS + GeneratorSteamUsageLBpS) * 20 * SteamVaporSpecVolumeAt100DegC1BarM3pKG;
+                }
+                else
+                {
+                    StackSteamVelocityMpS.Update(elapsedClockSeconds, (float)Math.Sqrt(KPa.FromPSI(Pressure_c_AtmPSI) * 0.5f * 1000 / WaterDensityAt100DegC1BarKGpM3));
+                    StackSteamVolumeM3pS = Kg.FromLb(CylinderSteamUsageLBpS + BlowerSteamUsageLBpS + RadiationSteamLossLBpS + CompSteamUsageLBpS + GeneratorSteamUsageLBpS) * 0.25f * SteamVaporSpecVolumeAt100DegC1BarM3pKG;
+
+                }    
+            }
+            else
+            {
+                StackSteamVelocityMpS.Update(elapsedClockSeconds, (float)Math.Sqrt(KPa.FromPSI(Pressure_c_AtmPSI) * 1000 * 2 / WaterDensityAt100DegC1BarKGpM3));
+                StackSteamVolumeM3pS = Kg.FromLb(CylinderSteamUsageLBpS + BlowerSteamUsageLBpS + RadiationSteamLossLBpS + CompSteamUsageLBpS + GeneratorSteamUsageLBpS) * SteamVaporSpecVolumeAt100DegC1BarM3pKG;
+            }
+
+
             float SmokeColorUnits = (RadiationSteamLossLBpS + CalculatedCarHeaterSteamUsageLBpS + BlowerBurnEffect + (SmokeColorDamper * SmokeColorFireMass)) / PreviousTotalSteamUsageLBpS - 0.2f;
             SmokeColor.Update(elapsedClockSeconds, MathHelper.Clamp(SmokeColorUnits, 0.25f, 1));
 

Source/RunActivity/Viewer3D/RollingStock/MSTSSteamLocomotiveViewer.cs

@@ -97,7 +97,10 @@ public MSTSSteamLocomotiveViewer(Viewer viewer, MSTSSteamLocomotive car)
                 else if (emitter.Key.ToLowerInvariant() == "cylinders42fx")
                     Cylinders42.AddRange(emitter.Value);
                 else if (emitter.Key.ToLowerInvariant() == "cylindersteamexhaust1fx")
+                {
                     CylinderSteamExhaust1.AddRange(emitter.Value);
+                    car.CylinderAdvancedSteamExhaustEffects = true;
+                }
                 else if (emitter.Key.ToLowerInvariant() == "cylindersteamexhaust2fx")
                     CylinderSteamExhaust2.AddRange(emitter.Value);
                 else if (emitter.Key.ToLowerInvariant() == "cylindersteamexhaust3fx")