diff --git a/apax/model/builder.py b/apax/model/builder.py
index 7a19ed65..95c48a27 100644
--- a/apax/model/builder.py
+++ b/apax/model/builder.py
@@ -19,7 +19,6 @@ def __init__(self, model_config: ModelConfig, n_species: int = 119):
         self.n_species = n_species
 
     def build_basis_function(self):
-
         basis_config = self.config["basis"]
         name = basis_config["name"]
 
diff --git a/apax/nodes/model.py b/apax/nodes/model.py
index 160cfc41..e32b77fb 100644
--- a/apax/nodes/model.py
+++ b/apax/nodes/model.py
@@ -3,6 +3,7 @@
 import typing as t
 
 import ase.io
+import numpy as np
 import pandas as pd
 import yaml
 import zntrack.utils
@@ -21,7 +22,7 @@ class ApaxBase(zntrack.Node):
 
 
 class Apax(ApaxBase):
-    """Class for the implementation of the apax model
+    """Class for traing Apax models
 
     Parameters
     ----------
@@ -32,19 +33,16 @@ class Apax(ApaxBase):
     validation_data: list[ase.Atoms]
         atoms object with the validation data set
     model: t.Optional[Apax]
-        model to be used as a base model
-    model_directory: pathlib.Path
-        model directory
-    train_data_file: pathlib.Path
-        output path to the training data
-    validation_data_file: pathlib.Path
-        output path to the validation data
+        model to be used as a base model for transfer learning
+    log_level: str
+        verbosity of logging during training
     """
 
     data: list = zntrack.deps()
     config: str = zntrack.params_path()
     validation_data = zntrack.deps()
     model: t.Optional[t.Any] = zntrack.deps(None)
+    log_level: str = zntrack.meta.Text("info")
 
     model_directory: pathlib.Path = zntrack.outs_path(zntrack.nwd / "apax_model")
 
@@ -84,20 +82,29 @@ def _handle_parameter_file(self):
 
     def train_model(self):
         """Train the model using `apax.train.run`"""
-        apax_run(self._parameter)
+        apax_run(self._parameter, log_level=self.log_level)
 
-    def get_metrics_from_plots(self):
+    def get_metrics(self):
         """In addition to the plots write a model metric"""
         metrics_df = pd.read_csv(self.model_directory / "log.csv")
-        self.metrics = metrics_df.iloc[-1].to_dict()
+        best_epoch = np.argmin(metrics_df["val_loss"])
+        self.metrics = metrics_df.iloc[best_epoch].to_dict()
 
     def run(self):
         """Primary method to run which executes all steps of the model training"""
-        ase.io.write(self.train_data_file, self.data)
-        ase.io.write(self.validation_data_file, self.validation_data)
+        if not self.state.restarted:
+            ase.io.write(self.train_data_file.as_posix(), self.data)
+            ase.io.write(self.validation_data_file.as_posix(), self.validation_data)
+
+        csv_path = self.model_directory / "log.csv"
+        if self.state.restarted and csv_path.is_file():
+            metrics_df = pd.read_csv(self.model_directory / "log.csv")
+
+            if metrics_df["epoch"].iloc[-1] >= self._parameter["n_epochs"] - 1:
+                return
 
         self.train_model()
-        self.get_metrics_from_plots()
+        self.get_metrics()
 
     def get_calculator(self, **kwargs):
         """Get an apax ase calculator"""
diff --git a/apax/train/callbacks.py b/apax/train/callbacks.py
index 1c99fc8f..bac4a428 100644
--- a/apax/train/callbacks.py
+++ b/apax/train/callbacks.py
@@ -13,11 +13,15 @@
 log = logging.getLogger(__name__)
 
 
+def format_str(k):
+    return f"{k:.5f}"
+
+
 class CSVLoggerApax(CSVLogger):
     def __init__(self, filename, separator=",", append=False):
-        super().__init__(filename, separator=",", append=False)
+        super().__init__(filename, separator=separator, append=append)
 
-    def on_test_batch_end(self, batch, logs=None):
+    def on_epoch_end(self, epoch, logs=None):
         logs = logs or {}
 
         def handle_value(k):
@@ -25,9 +29,51 @@ def handle_value(k):
             if isinstance(k, str):
                 return k
             elif isinstance(k, collections.abc.Iterable) and not is_zero_dim_ndarray:
-                return f"\"[{', '.join(map(str, k))}]\""
+                return f"\"[{', '.join(map(format_str, k))}]\""
             else:
+                return format_str(k)
+
+        if self.keys is None:
+            self.keys = sorted(logs.keys())
+            # When validation_freq > 1, `val_` keys are not in first epoch logs
+            # Add the `val_` keys so that its part of the fieldnames of writer.
+            val_keys_found = False
+            for key in self.keys:
+                if key.startswith("val_"):
+                    val_keys_found = True
+                    break
+            if not val_keys_found:
+                self.keys.extend(["val_" + k for k in self.keys])
+
+        if not self.writer:
+
+            class CustomDialect(csv.excel):
+                delimiter = self.sep
+
+            fieldnames = ["epoch"] + self.keys
+
+            self.writer = csv.DictWriter(
+                self.csv_file, fieldnames=fieldnames, dialect=CustomDialect
+            )
+            if self.append_header:
+                self.writer.writeheader()
+
+        row_dict = collections.OrderedDict({"epoch": epoch})
+        row_dict.update((key, handle_value(logs.get(key, "NA"))) for key in self.keys)
+        self.writer.writerow(row_dict)
+        self.csv_file.flush()
+
+    def on_test_batch_end(self, batch, logs=None):
+        logs = logs or {}
+
+        def handle_value(k):
+            is_zero_dim_ndarray = isinstance(k, np.ndarray) and k.ndim == 0
+            if isinstance(k, str):
                 return k
+            elif isinstance(k, collections.abc.Iterable) and not is_zero_dim_ndarray:
+                return f"\"[{', '.join(map(format_str, k))}]\""
+            else:
+                return format_str(k)
 
         if self.keys is None:
             self.keys = sorted(logs.keys())