diff --git a/src/TensorFlowNET.Core/TensorFlow.Binding.csproj b/src/TensorFlowNET.Core/TensorFlow.Binding.csproj
index 712e4aed..39279808 100644
--- a/src/TensorFlowNET.Core/TensorFlow.Binding.csproj
+++ b/src/TensorFlowNET.Core/TensorFlow.Binding.csproj
@@ -67,7 +67,6 @@ https://tensorflownet.readthedocs.io</Description>
   </ItemGroup>
 
   <ItemGroup>
-    <Folder Include="Estimators\" />
     <Folder Include="Keras\Initializers\" />
   </ItemGroup>
 </Project>
diff --git a/src/TensorFlowNET.Core/Train/AdamOptimizer.cs b/src/TensorFlowNET.Core/Training/AdamOptimizer.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/AdamOptimizer.cs
rename to src/TensorFlowNET.Core/Training/AdamOptimizer.cs
diff --git a/src/TensorFlowNET.Core/Train/AutoTrackable.cs b/src/TensorFlowNET.Core/Training/AutoTrackable.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/AutoTrackable.cs
rename to src/TensorFlowNET.Core/Training/AutoTrackable.cs
diff --git a/src/TensorFlowNET.Core/Train/Checkpointable/CheckpointableBase.cs b/src/TensorFlowNET.Core/Training/Checkpointable/CheckpointableBase.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Checkpointable/CheckpointableBase.cs
rename to src/TensorFlowNET.Core/Training/Checkpointable/CheckpointableBase.cs
diff --git a/src/TensorFlowNET.Core/Training/Coordinator.cs b/src/TensorFlowNET.Core/Training/Coordinator.cs
new file mode 100644
index 00000000..33c787b4
--- /dev/null
+++ b/src/TensorFlowNET.Core/Training/Coordinator.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tensorflow.Training
+{
+    /// <summary>
+    /// A coordinator for threads
+    /// </summary>
+    public class Coordinator
+    {
+    }
+}
diff --git a/src/TensorFlowNET.Core/Train/Distribute.cs b/src/TensorFlowNET.Core/Training/Distribute.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Distribute.cs
rename to src/TensorFlowNET.Core/Training/Distribute.cs
diff --git a/src/TensorFlowNET.Core/Train/ExponentialMovingAverage.cs b/src/TensorFlowNET.Core/Training/ExponentialMovingAverage.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/ExponentialMovingAverage.cs
rename to src/TensorFlowNET.Core/Training/ExponentialMovingAverage.cs
diff --git a/src/TensorFlowNET.Core/Train/GateGradientType.cs b/src/TensorFlowNET.Core/Training/GateGradientType.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/GateGradientType.cs
rename to src/TensorFlowNET.Core/Training/GateGradientType.cs
diff --git a/src/TensorFlowNET.Core/Train/GradientDescentOptimizer.cs b/src/TensorFlowNET.Core/Training/GradientDescentOptimizer.cs
similarity index 99%
rename from src/TensorFlowNET.Core/Train/GradientDescentOptimizer.cs
rename to src/TensorFlowNET.Core/Training/GradientDescentOptimizer.cs
index d4682066..73359c4b 100644
--- a/src/TensorFlowNET.Core/Train/GradientDescentOptimizer.cs
+++ b/src/TensorFlowNET.Core/Training/GradientDescentOptimizer.cs
@@ -1,26 +1,26 @@
-/*****************************************************************************
-   Copyright 2018 The TensorFlow.NET Authors. All Rights Reserved.
-
-   Licensed under the Apache License, Version 2.0 (the "License");
-   you may not use this file except in compliance with the License.
-   You may obtain a copy of the License at
-
-       http://www.apache.org/licenses/LICENSE-2.0
-
-   Unless required by applicable law or agreed to in writing, software
-   distributed under the License is distributed on an "AS IS" BASIS,
-   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-   See the License for the specific language governing permissions and
-   limitations under the License.
+/*****************************************************************************
+   Copyright 2018 The TensorFlow.NET Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
 ******************************************************************************/
 
 namespace Tensorflow.Train
 {
-    /// <summary>
-    /// Optimizer that implements the gradient descent algorithm.
+    /// <summary>
+    /// Optimizer that implements the gradient descent algorithm.
     /// </summary>
     public class GradientDescentOptimizer : Optimizer
-    {
+    {
         /// <summary>
         /// Construct a new gradient descent optimizer.
         /// </summary>
@@ -41,9 +41,9 @@ namespace Tensorflow.Train
         {
             _lr = learning_rate;
             _useTensor = false;
-        }
-
-        public GradientDescentOptimizer(Tensor learning_rate, bool use_locking = false, string name = "GradientDescent")
+        }
+
+        public GradientDescentOptimizer(Tensor learning_rate, bool use_locking = false, string name = "GradientDescent")
             : base(learning_rate, use_locking, name)
         {
             _lr_t = learning_rate;
@@ -52,10 +52,10 @@ namespace Tensorflow.Train
 
         public override void _prepare()
         {
-            if(!_useTensor)
-            {
-                var lr = _call_if_callable(_lr);
-                _lr_t = ops.convert_to_tensor(lr, name: "learning_rate");
+            if(!_useTensor)
+            {
+                var lr = _call_if_callable(_lr);
+                _lr_t = ops.convert_to_tensor(lr, name: "learning_rate");
             }
             
         }
diff --git a/src/TensorFlowNET.Core/Train/Optimizer.cs b/src/TensorFlowNET.Core/Training/Optimizer.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Optimizer.cs
rename to src/TensorFlowNET.Core/Training/Optimizer.cs
diff --git a/src/TensorFlowNET.Core/Train/QueueRunner.cs b/src/TensorFlowNET.Core/Training/QueueRunner.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/QueueRunner.cs
rename to src/TensorFlowNET.Core/Training/QueueRunner.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/BaseSaverBuilder.cs b/src/TensorFlowNET.Core/Training/Saving/BaseSaverBuilder.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/BaseSaverBuilder.cs
rename to src/TensorFlowNET.Core/Training/Saving/BaseSaverBuilder.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/BulkSaverBuilder.cs b/src/TensorFlowNET.Core/Training/Saving/BulkSaverBuilder.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/BulkSaverBuilder.cs
rename to src/TensorFlowNET.Core/Training/Saving/BulkSaverBuilder.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/ISaverBuilder.cs b/src/TensorFlowNET.Core/Training/Saving/ISaverBuilder.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/ISaverBuilder.cs
rename to src/TensorFlowNET.Core/Training/Saving/ISaverBuilder.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/ReferenceVariableSaveable.cs b/src/TensorFlowNET.Core/Training/Saving/ReferenceVariableSaveable.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/ReferenceVariableSaveable.cs
rename to src/TensorFlowNET.Core/Training/Saving/ReferenceVariableSaveable.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/ResourceVariableSaveable.cs b/src/TensorFlowNET.Core/Training/Saving/ResourceVariableSaveable.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/ResourceVariableSaveable.cs
rename to src/TensorFlowNET.Core/Training/Saving/ResourceVariableSaveable.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/SaveSpec.cs b/src/TensorFlowNET.Core/Training/Saving/SaveSpec.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/SaveSpec.cs
rename to src/TensorFlowNET.Core/Training/Saving/SaveSpec.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/SaveableObject.cs b/src/TensorFlowNET.Core/Training/Saving/SaveableObject.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/SaveableObject.cs
rename to src/TensorFlowNET.Core/Training/Saving/SaveableObject.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/Saver.cs b/src/TensorFlowNET.Core/Training/Saving/Saver.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/Saver.cs
rename to src/TensorFlowNET.Core/Training/Saving/Saver.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/checkpoint_management.py.cs b/src/TensorFlowNET.Core/Training/Saving/checkpoint_management.py.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/checkpoint_management.py.cs
rename to src/TensorFlowNET.Core/Training/Saving/checkpoint_management.py.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/saveable_object_util.py.cs b/src/TensorFlowNET.Core/Training/Saving/saveable_object_util.py.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/saveable_object_util.py.cs
rename to src/TensorFlowNET.Core/Training/Saving/saveable_object_util.py.cs
diff --git a/src/TensorFlowNET.Core/Train/Saving/saver.py.cs b/src/TensorFlowNET.Core/Training/Saving/saver.py.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Saving/saver.py.cs
rename to src/TensorFlowNET.Core/Training/Saving/saver.py.cs
diff --git a/src/TensorFlowNET.Core/Training/SecondOrStepTimer.cs b/src/TensorFlowNET.Core/Training/SecondOrStepTimer.cs
new file mode 100644
index 00000000..fe13405f
--- /dev/null
+++ b/src/TensorFlowNET.Core/Training/SecondOrStepTimer.cs
@@ -0,0 +1,43 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tensorflow.Training
+{
+    public class SecondOrStepTimer : _HookTimer
+    {
+        int _every_secs = 60;
+        int _every_steps = 0;
+        int _last_triggered_step = 0;
+        int _last_triggered_time = 0;
+
+        public SecondOrStepTimer(int every_secs, int every_steps)
+        {
+            _every_secs = every_secs;
+            _every_steps = every_steps;
+        }
+
+        public override void reset()
+        {
+            _last_triggered_step = 0;
+            _last_triggered_time = 0;
+        }
+
+        public override int last_triggered_step()
+        {
+            return _last_triggered_step;
+        }
+
+        public override bool should_trigger_for_step(int step)
+        {
+            throw new NotImplementedException();
+        }
+
+        public override void update_last_triggered_step(int step)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}
diff --git a/src/TensorFlowNET.Core/Train/SessionRunArgs.cs b/src/TensorFlowNET.Core/Training/SessionRunArgs.cs
similarity index 79%
rename from src/TensorFlowNET.Core/Train/SessionRunArgs.cs
rename to src/TensorFlowNET.Core/Training/SessionRunArgs.cs
index 00d473e1..7c089634 100644
--- a/src/TensorFlowNET.Core/Train/SessionRunArgs.cs
+++ b/src/TensorFlowNET.Core/Training/SessionRunArgs.cs
@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using System.Text;
 
-namespace Tensorflow.Train
+namespace Tensorflow.Training
 {
     public class SessionRunArgs
     {
diff --git a/src/TensorFlowNET.Core/Train/SessionRunContext.cs b/src/TensorFlowNET.Core/Training/SessionRunContext.cs
similarity index 95%
rename from src/TensorFlowNET.Core/Train/SessionRunContext.cs
rename to src/TensorFlowNET.Core/Training/SessionRunContext.cs
index cf8bdc05..6c119593 100644
--- a/src/TensorFlowNET.Core/Train/SessionRunContext.cs
+++ b/src/TensorFlowNET.Core/Training/SessionRunContext.cs
@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using System.Text;
 
-namespace Tensorflow.Train
+namespace Tensorflow.Training
 {
     public class SessionRunContext
     {
diff --git a/src/TensorFlowNET.Core/Training/SessionRunHook.cs b/src/TensorFlowNET.Core/Training/SessionRunHook.cs
new file mode 100644
index 00000000..ce3a2200
--- /dev/null
+++ b/src/TensorFlowNET.Core/Training/SessionRunHook.cs
@@ -0,0 +1,52 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tensorflow.Training
+{
+    /// <summary>
+    /// Hook to extend calls to MonitoredSession.run().
+    /// </summary>
+    public abstract class SessionRunHook
+    {
+        /// <summary>
+        /// Called once before using the session.
+        /// </summary>
+        public virtual void begin()
+        {
+        }
+
+        /// <summary>
+        /// Called when new TensorFlow session is created.
+        /// </summary>
+        /// <param name="session"></param>
+        /// <param name="coord"></param>
+        public virtual void after_create_session(Session session, Coordinator coord)
+        {
+        }
+
+        /// <summary>
+        /// Called before each call to run().
+        /// </summary>
+        /// <param name="run_context"></param>
+        public virtual void before_run(SessionRunContext run_context)
+        {
+        }
+
+        /// <summary>
+        /// Called after each call to run().
+        /// </summary>
+        public virtual void after_run(SessionRunContext run_context, SessionRunValues run_values)
+        {
+        }
+
+        /// <summary>
+        /// Called at the end of session.
+        /// </summary>
+        public virtual void end(Session session)
+        {
+        }
+    }
+}
diff --git a/src/TensorFlowNET.Core/Train/SessionRunValues.cs b/src/TensorFlowNET.Core/Training/SessionRunValues.cs
similarity index 80%
rename from src/TensorFlowNET.Core/Train/SessionRunValues.cs
rename to src/TensorFlowNET.Core/Training/SessionRunValues.cs
index 655c3310..d93e8347 100644
--- a/src/TensorFlowNET.Core/Train/SessionRunValues.cs
+++ b/src/TensorFlowNET.Core/Training/SessionRunValues.cs
@@ -2,7 +2,7 @@
 using System.Collections.Generic;
 using System.Text;
 
-namespace Tensorflow.Train
+namespace Tensorflow.Training
 {
     public class SessionRunValues
     {
diff --git a/src/TensorFlowNET.Core/Train/SlotCreator.cs b/src/TensorFlowNET.Core/Training/SlotCreator.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/SlotCreator.cs
rename to src/TensorFlowNET.Core/Training/SlotCreator.cs
diff --git a/src/TensorFlowNET.Core/Train/Trackable.cs b/src/TensorFlowNET.Core/Training/Trackable.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/Trackable.cs
rename to src/TensorFlowNET.Core/Training/Trackable.cs
diff --git a/src/TensorFlowNET.Core/Train/TrainingUtil.cs b/src/TensorFlowNET.Core/Training/TrainingUtil.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/TrainingUtil.cs
rename to src/TensorFlowNET.Core/Training/TrainingUtil.cs
diff --git a/src/TensorFlowNET.Core/Train/VariableAggregationType.cs b/src/TensorFlowNET.Core/Training/VariableAggregationType.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/VariableAggregationType.cs
rename to src/TensorFlowNET.Core/Training/VariableAggregationType.cs
diff --git a/src/TensorFlowNET.Core/Training/_HookTimer.cs b/src/TensorFlowNET.Core/Training/_HookTimer.cs
new file mode 100644
index 00000000..295de165
--- /dev/null
+++ b/src/TensorFlowNET.Core/Training/_HookTimer.cs
@@ -0,0 +1,38 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tensorflow.Training
+{
+    /// <summary>
+    /// Base timer for determining when Hooks should trigger.
+    /// </summary>
+    public abstract class _HookTimer
+    {
+        /// <summary>
+        /// Resets the timer.
+        /// </summary>
+        public abstract void reset();
+
+        /// <summary>
+        /// Return true if the timer should trigger for the specified step.
+        /// </summary>
+        /// <param name="step"></param>
+        /// <returns></returns>
+        public abstract bool should_trigger_for_step(int step);
+
+        /// <summary>
+        /// Update the last triggered time and step number.
+        /// </summary>
+        /// <param name="step"></param>
+        public abstract void update_last_triggered_step(int step);
+
+        /// <summary>
+        /// Returns the last triggered time step or None if never triggered.
+        /// </summary>
+        /// <returns></returns>
+        public abstract int last_triggered_step();
+    }
+}
diff --git a/src/TensorFlowNET.Core/Train/_MonitoredSession.cs b/src/TensorFlowNET.Core/Training/_MonitoredSession.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/_MonitoredSession.cs
rename to src/TensorFlowNET.Core/Training/_MonitoredSession.cs
diff --git a/src/TensorFlowNET.Core/Train/_OptimizableVariable.cs b/src/TensorFlowNET.Core/Training/_OptimizableVariable.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/_OptimizableVariable.cs
rename to src/TensorFlowNET.Core/Training/_OptimizableVariable.cs
diff --git a/src/TensorFlowNET.Core/Train/gen_training_ops.py.cs b/src/TensorFlowNET.Core/Training/gen_training_ops.py.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/gen_training_ops.py.cs
rename to src/TensorFlowNET.Core/Training/gen_training_ops.py.cs
diff --git a/src/TensorFlowNET.Core/Train/moving_averages.cs b/src/TensorFlowNET.Core/Training/moving_averages.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/moving_averages.cs
rename to src/TensorFlowNET.Core/Training/moving_averages.cs
diff --git a/src/TensorFlowNET.Core/Train/optimizer.py.cs b/src/TensorFlowNET.Core/Training/optimizer.py.cs
similarity index 100%
rename from src/TensorFlowNET.Core/Train/optimizer.py.cs
rename to src/TensorFlowNET.Core/Training/optimizer.py.cs