diff --git a/src/TensorFlowNET.Core/Estimators/Estimator.cs b/src/TensorFlowNET.Core/Estimators/Estimator.cs
index 0df59dcc..5ba7a9c3 100644
--- a/src/TensorFlowNET.Core/Estimators/Estimator.cs
+++ b/src/TensorFlowNET.Core/Estimators/Estimator.cs
@@ -45,8 +45,9 @@ namespace Tensorflow.Estimators
                 }
             }
 
-            _train_model(input_fn);
-            throw new NotImplementedException("");
+            var loss = _train_model(input_fn);
+            print($"Loss for final step: {loss}.");
+            return this;
         }
 
         private int _load_global_step_from_checkpoint_dir(string checkpoint_dir)
@@ -58,12 +59,12 @@ namespace Tensorflow.Estimators
             return cp.AllModelCheckpointPaths.Count - 1;
         }
 
-        private void _train_model(Func<DatasetV1Adapter> input_fn)
+        private Tensor _train_model(Func<DatasetV1Adapter> input_fn)
         {
-            _train_model_default(input_fn);
+            return _train_model_default(input_fn);
         }
 
-        private void _train_model_default(Func<DatasetV1Adapter> input_fn)
+        private Tensor _train_model_default(Func<DatasetV1Adapter> input_fn)
         {
             using (var g = tf.Graph().as_default())
             {
@@ -74,13 +75,16 @@ namespace Tensorflow.Estimators
                 if (global_step_tensor != null)
                     TrainingUtil._get_or_create_global_step_read(g);
 
-                _get_features_and_labels_from_input_fn(input_fn, "train");
+                var (features, labels) = _get_features_and_labels_from_input_fn(input_fn, "train");
             }
+
+            throw new NotImplementedException("");
         }
 
-        private void _get_features_and_labels_from_input_fn(Func<DatasetV1Adapter> input_fn, string mode)
+        private (Dictionary<string, Tensor>, Dictionary<string, Tensor>) _get_features_and_labels_from_input_fn(Func<DatasetV1Adapter> input_fn, string mode)
         {
-            _call_input_fn(input_fn, mode);
+            var result = _call_input_fn(input_fn, mode);
+            return EstimatorUtil.parse_input_fn_result(result);
         }
 
         /// <summary>
@@ -88,9 +92,9 @@ namespace Tensorflow.Estimators
         /// </summary>
         /// <param name="input_fn"></param>
         /// <param name="mode"></param>
-        private void _call_input_fn(Func<DatasetV1Adapter> input_fn, string mode)
+        private DatasetV1Adapter _call_input_fn(Func<DatasetV1Adapter> input_fn, string mode)
         {
-            input_fn();
+            return input_fn();
         }
 
         private Tensor _create_and_assert_global_step(Graph graph)
diff --git a/src/TensorFlowNET.Core/Estimators/EstimatorUtil.cs b/src/TensorFlowNET.Core/Estimators/EstimatorUtil.cs
new file mode 100644
index 00000000..df1fb38b
--- /dev/null
+++ b/src/TensorFlowNET.Core/Estimators/EstimatorUtil.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using Tensorflow.Data;
+
+namespace Tensorflow.Estimators
+{
+    public class EstimatorUtil
+    {
+        public static (Dictionary<string, Tensor>, Dictionary<string, Tensor>) parse_input_fn_result(DatasetV1Adapter result)
+        {
+            throw new NotImplementedException("");
+        }
+    }
+}
diff --git a/src/TensorFlowNET.Models/ObjectDetection/Builders/BoxPredictorBuilder.cs b/src/TensorFlowNET.Models/ObjectDetection/Builders/BoxPredictorBuilder.cs
new file mode 100644
index 00000000..7ff2be25
--- /dev/null
+++ b/src/TensorFlowNET.Models/ObjectDetection/Builders/BoxPredictorBuilder.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow.Models.ObjectDetection
+{
+    public class BoxPredictorBuilder
+    {
+        ConvolutionalBoxPredictor _first_stage_box_predictor;
+        public ConvolutionalBoxPredictor build_convolutional_box_predictor()
+        {
+            throw new NotImplementedException("");
+        }
+    }
+}
diff --git a/src/TensorFlowNET.Models/ObjectDetection/Builders/ImageResizerBuilder.cs b/src/TensorFlowNET.Models/ObjectDetection/Builders/ImageResizerBuilder.cs
index eab1e8a5..81c169b3 100644
--- a/src/TensorFlowNET.Models/ObjectDetection/Builders/ImageResizerBuilder.cs
+++ b/src/TensorFlowNET.Models/ObjectDetection/Builders/ImageResizerBuilder.cs
@@ -13,6 +13,11 @@ namespace Tensorflow.Models.ObjectDetection
 
         }
 
+        /// <summary>
+        /// Builds callable for image resizing operations.
+        /// </summary>
+        /// <param name="image_resizer_config"></param>
+        /// <returns></returns>
         public Action build(ImageResizer image_resizer_config)
         {
             var image_resizer_oneof = image_resizer_config.ImageResizerOneofCase;
@@ -21,8 +26,13 @@ namespace Tensorflow.Models.ObjectDetection
                 var keep_aspect_ratio_config = image_resizer_config.KeepAspectRatioResizer;
                 var method = _tf_resize_method(keep_aspect_ratio_config.ResizeMethod);
                 var per_channel_pad_value = new[] { 0, 0, 0 };
-                //if (keep_aspect_ratio_config.PerChannelPadValue != null)
-                    //per_channel_pad_value = new[] { keep_aspect_ratio_config.PerChannelPadValue };
+                if (keep_aspect_ratio_config.PerChannelPadValue.Count > 0)
+                    throw new NotImplementedException("");
+                // per_channel_pad_value = new[] { keep_aspect_ratio_config.PerChannelPadValue. };
+                return () =>
+                {
+
+                };
             }
             else
             {
diff --git a/src/TensorFlowNET.Models/ObjectDetection/Builders/ModelBuilder.cs b/src/TensorFlowNET.Models/ObjectDetection/Builders/ModelBuilder.cs
index 1493352a..0ff80561 100644
--- a/src/TensorFlowNET.Models/ObjectDetection/Builders/ModelBuilder.cs
+++ b/src/TensorFlowNET.Models/ObjectDetection/Builders/ModelBuilder.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Text;
-using Tensorflow.Models.ObjectDetection.MetaArchitectures;
 using Tensorflow.Models.ObjectDetection.Protos;
 using static Tensorflow.Models.ObjectDetection.Protos.DetectionModel;
 
@@ -45,7 +44,20 @@ namespace Tensorflow.Models.ObjectDetection
         {
             var num_classes = frcnn_config.NumClasses;
             var image_resizer_fn = image_resizer_builder.build(frcnn_config.ImageResizer);
-            throw new NotImplementedException("");
+
+            var first_stage_atrous_rate = frcnn_config.FirstStageAtrousRate;
+            var number_of_stages = frcnn_config.NumberOfStages;
+
+            return new FasterRCNNMetaArch(new FasterRCNNInitArgs
+            {
+                is_training = is_training,
+                num_classes = num_classes,
+                image_resizer_fn = image_resizer_fn,
+                feature_extractor = () => { throw new NotImplementedException(""); },
+                number_of_stage = number_of_stages,
+                first_stage_anchor_generator = null,
+                first_stage_atrous_rate = first_stage_atrous_rate
+            });
         }
 
         public Action preprocess()
diff --git a/src/TensorFlowNET.Models/ObjectDetection/Core/DetectionModel.cs b/src/TensorFlowNET.Models/ObjectDetection/Core/DetectionModel.cs
new file mode 100644
index 00000000..24578a5b
--- /dev/null
+++ b/src/TensorFlowNET.Models/ObjectDetection/Core/DetectionModel.cs
@@ -0,0 +1,10 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow.Models.ObjectDetection.Core
+{
+    public abstract class DetectionModel
+    {
+    }
+}
diff --git a/src/TensorFlowNET.Models/ObjectDetection/Inputs.cs b/src/TensorFlowNET.Models/ObjectDetection/Inputs.cs
index eb300752..0388b78a 100644
--- a/src/TensorFlowNET.Models/ObjectDetection/Inputs.cs
+++ b/src/TensorFlowNET.Models/ObjectDetection/Inputs.cs
@@ -2,8 +2,6 @@
 using System.Collections.Generic;
 using System.Text;
 using Tensorflow.Data;
-using Tensorflow.Estimators;
-using Tensorflow.Models.ObjectDetection.MetaArchitectures;
 using Tensorflow.Models.ObjectDetection.Protos;
 
 namespace Tensorflow.Models.ObjectDetection
@@ -23,9 +21,7 @@ namespace Tensorflow.Models.ObjectDetection
         public Func<DatasetV1Adapter> create_train_input_fn(TrainConfig train_config, InputReader train_input_config, DetectionModel model_config)
         {
             Func<DatasetV1Adapter> _train_input_fn = () =>
-            {
-                return train_input(train_config, train_input_config, model_config);
-            };
+                train_input(train_config, train_input_config, model_config);
 
             return _train_input_fn;
         }
diff --git a/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNInitArgs.cs b/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNInitArgs.cs
new file mode 100644
index 00000000..991ffff4
--- /dev/null
+++ b/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNInitArgs.cs
@@ -0,0 +1,18 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow.Models.ObjectDetection
+{
+    public class FasterRCNNInitArgs
+    {
+        public bool is_training { get; set; }
+        public int num_classes { get; set; }
+        public Action image_resizer_fn { get; set; }
+        public Action feature_extractor { get; set; }
+        public int number_of_stage { get; set; }
+        public object first_stage_anchor_generator { get; set; }
+        public object first_stage_target_assigner { get; set; }
+        public int first_stage_atrous_rate { get; set; }
+    }
+}
diff --git a/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNMetaArch.cs b/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNMetaArch.cs
index 5a4c4e5a..083d4e4f 100644
--- a/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNMetaArch.cs
+++ b/src/TensorFlowNET.Models/ObjectDetection/MetaArchitectures/FasterRCNNMetaArch.cs
@@ -2,10 +2,17 @@
 using System.Collections.Generic;
 using System.Text;
 
-namespace Tensorflow.Models.ObjectDetection.MetaArchitectures
+namespace Tensorflow.Models.ObjectDetection
 {
-    public class FasterRCNNMetaArch
+    public class FasterRCNNMetaArch : Core.DetectionModel
     {
+        FasterRCNNInitArgs _args;
+
+        public FasterRCNNMetaArch(FasterRCNNInitArgs args)
+        {
+            _args = args;
+        }
+
         public (Tensor, Tensor) preprocess(Tensor tensor)
         {
             throw new NotImplementedException("");
diff --git a/src/TensorFlowNET.Models/ObjectDetection/Predictors/ConvolutionalBoxPredictor.cs b/src/TensorFlowNET.Models/ObjectDetection/Predictors/ConvolutionalBoxPredictor.cs
new file mode 100644
index 00000000..bd2f4114
--- /dev/null
+++ b/src/TensorFlowNET.Models/ObjectDetection/Predictors/ConvolutionalBoxPredictor.cs
@@ -0,0 +1,10 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace Tensorflow.Models.ObjectDetection
+{
+    public class ConvolutionalBoxPredictor
+    {
+    }
+}