Fix null value for equipment

Author: cesarBLG

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

@@ -236,7 +236,7 @@ public enum WindowState
         public float BearingHotBoxSmokeDurationS;
         public float BearingHotBoxSmokeVelocityMpS = 15.0f;
         public Color BearingHotBoxSmokeSteadyColor = Color.Gray;
-        List<string> BrakeEquipment;
+        List<string> BrakeEquipment = new List<string>();
 
         /// <summary>
         /// Indicates whether a non auto (straight) brake is present or not when braking is selected.