diff --git a/gprMax/cmds_singleuse.py b/gprMax/cmds_singleuse.py
index e41caa26..616133ef 100644
--- a/gprMax/cmds_singleuse.py
+++ b/gprMax/cmds_singleuse.py
@@ -202,11 +202,10 @@ class TimeStepStabilityFactor(UserObjectSingle):
             )
             raise ValueError
 
-        G = model.G
-        G.dt_mod = f
-        G.dt = G.dt * G.dt_mod
+        model.dt_mod = f
+        model.G.dt *= model.dt_mod
 
-        logger.info(f"Time step (modified): {G.dt:g} secs")
+        logger.info(f"Time step (modified): {model.G.dt:g} secs")
 
 
 class TimeWindow(UserObjectSingle):
diff --git a/gprMax/grid/fdtd_grid.py b/gprMax/grid/fdtd_grid.py
index edef7b9a..403f97f0 100644
--- a/gprMax/grid/fdtd_grid.py
+++ b/gprMax/grid/fdtd_grid.py
@@ -59,7 +59,6 @@ class FDTDGrid:
         self.dl: np.ndarray[Any, np.dtype[np.single]]
         self.dt = 0.0
 
-        self.dt_mod = 1.0  # Time step stability factor
         self.iteration = 0  # Current iteration number
         self.iterations = 0  # Total number of iterations
         self.timewindow = 0
diff --git a/gprMax/model.py b/gprMax/model.py
index f7ef08c1..06211c11 100644
--- a/gprMax/model.py
+++ b/gprMax/model.py
@@ -60,6 +60,8 @@ class Model:
         self.gny = 0
         self.gnz = 0
 
+        self.dt_mod = 1.0  # Time step stability factor
+
         self.G = self._create_grid()
         # Monitor memory usage
         self.p = None
@@ -126,6 +128,14 @@ class Model:
     def dl(self, value: np.ndarray[Any, np.dtype[np.single]]):
         self.G.dl = value
 
+    @property
+    def dt(self) -> float:
+        return self.G.dt
+
+    @dt.setter
+    def dt(self, value: float):
+        self.G.dt = value
+
     def _create_grid(self) -> FDTDGrid:
         """Create grid object according to solver.