diff --git a/src/primaite/__init__.py b/src/primaite/__init__.py
index 24815727..64857c80 100644
--- a/src/primaite/__init__.py
+++ b/src/primaite/__init__.py
@@ -21,6 +21,7 @@ _PLATFORM_DIRS: Final[PlatformDirs] = PlatformDirs(appname="primaite")
 def _get_primaite_config():
     config_path = _PLATFORM_DIRS.user_config_path / "primaite_config.yaml"
     if not config_path.exists():
+
         config_path = Path(
             pkg_resources.resource_filename(
                 "primaite", "setup/_package_data/primaite_config.yaml"
@@ -36,7 +37,7 @@ def _get_primaite_config():
         "ERROR": logging.ERROR,
         "CRITICAL": logging.CRITICAL,
     }
-    primaite_config["log_level"] = log_level_map[primaite_config["log_level"]]
+    primaite_config["log_level"] = log_level_map[primaite_config["logging"]["log_level"]]
     return primaite_config
 
 
@@ -108,11 +109,11 @@ def _log_dir() -> Path:
 
 _LEVEL_FORMATTER: Final[_LevelFormatter] = _LevelFormatter(
     {
-        logging.DEBUG: _PRIMAITE_CONFIG["logger_format"]["DEBUG"],
-        logging.INFO: _PRIMAITE_CONFIG["logger_format"]["INFO"],
-        logging.WARNING: _PRIMAITE_CONFIG["logger_format"]["WARNING"],
-        logging.ERROR: _PRIMAITE_CONFIG["logger_format"]["ERROR"],
-        logging.CRITICAL: _PRIMAITE_CONFIG["logger_format"]["CRITICAL"]
+        logging.DEBUG: _PRIMAITE_CONFIG["logging"]["logger_format"]["DEBUG"],
+        logging.INFO: _PRIMAITE_CONFIG["logging"]["logger_format"]["INFO"],
+        logging.WARNING: _PRIMAITE_CONFIG["logging"]["logger_format"]["WARNING"],
+        logging.ERROR: _PRIMAITE_CONFIG["logging"]["logger_format"]["ERROR"],
+        logging.CRITICAL: _PRIMAITE_CONFIG["logging"]["logger_format"]["CRITICAL"]
     }
 )
 
@@ -132,10 +133,10 @@ _FILE_HANDLER: Final[RotatingFileHandler] = RotatingFileHandler(
     backupCount=9,  # Max 100MB of logs
     encoding="utf8",
 )
-_STREAM_HANDLER.setLevel(_PRIMAITE_CONFIG["log_level"])
-_FILE_HANDLER.setLevel(_PRIMAITE_CONFIG["log_level"])
+_STREAM_HANDLER.setLevel(_PRIMAITE_CONFIG["logging"]["log_level"])
+_FILE_HANDLER.setLevel(_PRIMAITE_CONFIG["logging"]["log_level"])
 
-_LOG_FORMAT_STR: Final[str] = _PRIMAITE_CONFIG["logger_format"]
+_LOG_FORMAT_STR: Final[str] = _PRIMAITE_CONFIG["logging"]["logger_format"]
 _STREAM_HANDLER.setFormatter(_LEVEL_FORMATTER)
 _FILE_HANDLER.setFormatter(_LEVEL_FORMATTER)
 
@@ -145,7 +146,7 @@ _LOGGER.addHandler(_STREAM_HANDLER)
 _LOGGER.addHandler(_FILE_HANDLER)
 
 
-def getLogger(name: str) -> Logger:
+def getLogger(name: str) -> Logger:  # noqa
     """
     Get a PrimAITE logger.
 
diff --git a/src/primaite/agents/agent.py b/src/primaite/agents/agent.py
index 5f4dac8f..05133b7e 100644
--- a/src/primaite/agents/agent.py
+++ b/src/primaite/agents/agent.py
@@ -64,7 +64,11 @@ class AgentSessionABC(ABC):
         "The session timestamp"
         self.session_path = _get_session_path(self.session_timestamp)
         "The Session path"
-        self.checkpoints_path = self.session_path / "checkpoints"
+        self.learning_path = self.session_path / "learning"
+        "The learning outputs path"
+        self.evaluation_path = self.session_path / "evaluation"
+        "The evaluation outputs path"
+        self.checkpoints_path = self.learning_path / "checkpoints"
         self.checkpoints_path.mkdir(parents=True, exist_ok=True)
         "The Session checkpoints path"
 
@@ -205,7 +209,6 @@ class HardCodedAgentSessionABC(AgentSessionABC):
         self._env: Primaite = Primaite(
             training_config_path=self._training_config_path,
             lay_down_config_path=self._lay_down_config_path,
-            transaction_list=[],
             session_path=self.session_path,
             timestamp_str=self.timestamp_str
         )
diff --git a/src/primaite/agents/rllib.py b/src/primaite/agents/rllib.py
index 710225d7..8a6428bb 100644
--- a/src/primaite/agents/rllib.py
+++ b/src/primaite/agents/rllib.py
@@ -21,7 +21,6 @@ def _env_creator(env_config):
     return Primaite(
         training_config_path=env_config["training_config_path"],
         lay_down_config_path=env_config["lay_down_config_path"],
-        transaction_list=env_config["transaction_list"],
         session_path=env_config["session_path"],
         timestamp_str=env_config["timestamp_str"]
     )
@@ -106,7 +105,6 @@ class RLlibAgent(AgentSessionABC):
             env_config=dict(
                 training_config_path=self._training_config_path,
                 lay_down_config_path=self._lay_down_config_path,
-                transaction_list=[],
                 session_path=self.session_path,
                 timestamp_str=self.timestamp_str
             )
diff --git a/src/primaite/agents/sb3.py b/src/primaite/agents/sb3.py
index 4d2ded6b..c183c544 100644
--- a/src/primaite/agents/sb3.py
+++ b/src/primaite/agents/sb3.py
@@ -34,7 +34,7 @@ class SB3Agent(AgentSessionABC):
             _LOGGER.error(msg)
             raise ValueError(msg)
 
-        self._tensorboard_log_path = self.session_path / "tensorboard_logs"
+        self._tensorboard_log_path = self.learning_path / "tensorboard_logs"
         self._tensorboard_log_path.mkdir(parents=True, exist_ok=True)
         self._setup()
         _LOGGER.debug(
@@ -49,7 +49,6 @@ class SB3Agent(AgentSessionABC):
         self._env = Primaite(
             training_config_path=self._training_config_path,
             lay_down_config_path=self._lay_down_config_path,
-            transaction_list=[],
             session_path=self.session_path,
             timestamp_str=self.timestamp_str
         )
@@ -108,10 +107,13 @@ class SB3Agent(AgentSessionABC):
 
         if not episodes:
             episodes = self._training_config.num_episodes
-
-        _LOGGER.info(f"Beginning evaluation for {episodes} episodes @"
-                     f" {time_steps} time steps...")
-
+        self._env.set_as_eval()
+        if deterministic:
+            deterministic_str = "deterministic"
+        else:
+            deterministic_str = "non-deterministic"
+        _LOGGER.info(f"Beginning {deterministic_str} evaluation for "
+                     f"{episodes} episodes @ {time_steps} time steps...")
         for episode in range(episodes):
             obs = self._env.reset()
 
@@ -123,6 +125,7 @@ class SB3Agent(AgentSessionABC):
                 if isinstance(action, np.ndarray):
                     action = np.int64(action)
                 obs, rewards, done, info = self._env.step(action)
+        _LOGGER.info(f"Finished evaluation")
 
     @classmethod
     def load(self):
diff --git a/src/primaite/config/_package_data/training/training_config_main.yaml b/src/primaite/config/_package_data/training/training_config_main.yaml
index 9cbcb702..0e0212f4 100644
--- a/src/primaite/config/_package_data/training/training_config_main.yaml
+++ b/src/primaite/config/_package_data/training/training_config_main.yaml
@@ -38,7 +38,7 @@ hard_coded_agent_view: FULL
 action_type: ANY
 
 # Number of episodes to run per session
-num_episodes: 10
+num_episodes: 1000
 
 # Number of time_steps per episode
 num_steps: 256
diff --git a/src/primaite/environment/primaite_env.py b/src/primaite/environment/primaite_env.py
index 5319d0f1..5b344a99 100644
--- a/src/primaite/environment/primaite_env.py
+++ b/src/primaite/environment/primaite_env.py
@@ -1,10 +1,6 @@
 # Crown Copyright (C) Dstl 2022. DEFCON 703. Shared in confidence.
 """Main environment module containing the PRIMmary AI Training Evironment (Primaite) class."""
 import copy
-import csv
-import logging
-import time
-from datetime import datetime
 from pathlib import Path
 from typing import Dict, Tuple, Union, Final
 
@@ -14,6 +10,7 @@ import yaml
 from gym import Env, spaces
 from matplotlib import pyplot as plt
 
+from primaite import getLogger
 from primaite.acl.access_control_list import AccessControlList
 from primaite.agents.utils import is_valid_acl_action_extra, \
     is_valid_node_action
@@ -27,7 +24,7 @@ from primaite.common.enums import (
     NodeType,
     ObservationType,
     Priority,
-    SoftwareState,
+    SoftwareState, SessionType,
 )
 from primaite.common.service import Service
 from primaite.config import training_config
@@ -47,11 +44,9 @@ from primaite.pol.ier import IER
 from primaite.pol.red_agent_pol import apply_red_agent_iers, \
     apply_red_agent_node_pol
 from primaite.transactions.transaction import Transaction
-from primaite.transactions.transactions_to_file import \
-    write_transaction_to_file
+from primaite.utils.session_output_writer import SessionOutputWriter
 
-_LOGGER = logging.getLogger(__name__)
-_LOGGER.setLevel(logging.INFO)
+_LOGGER = getLogger(__name__)
 
 
 class Primaite(Env):
@@ -67,7 +62,6 @@ class Primaite(Env):
             self,
             training_config_path: Union[str, Path],
             lay_down_config_path: Union[str, Path],
-            transaction_list,
             session_path: Path,
             timestamp_str: str,
     ):
@@ -76,7 +70,6 @@ class Primaite(Env):
 
         :param training_config_path: The training config filepath.
         :param lay_down_config_path: The lay down config filepath.
-        :param transaction_list: The list of transactions to populate.
         :param session_path: The directory path the session is writing to.
         :param timestamp_str: The session timestamp in the format:
             <yyyy-mm-dd>_<hh-mm-ss>.
@@ -96,9 +89,6 @@ class Primaite(Env):
 
         super(Primaite, self).__init__()
 
-        # Transaction list
-        self.transaction_list = transaction_list
-
         # The agent in use
         self.agent_identifier = self.training_config.agent_identifier
 
@@ -245,20 +235,31 @@ class Primaite(Env):
             _LOGGER.error(
                 f"Invalid action type selected: {self.training_config.action_type}"
             )
-        # Set up a csv to store the results of the training
-        try:
-            header = ["Episode", "Average Reward"]
 
-            file_name = f"average_reward_per_episode_{timestamp_str}.csv"
-            file_path = session_path / file_name
-            self.csv_file = open(file_path, "w", encoding="UTF8", newline="")
-            self.csv_writer = csv.writer(self.csv_file)
-            self.csv_writer.writerow(header)
-        except Exception:
-            _LOGGER.error(
-                "Could not create csv file to hold average reward per episode"
-            )
-            _LOGGER.error("Exception occured", exc_info=True)
+        self.episode_av_reward_writer = SessionOutputWriter(
+            self,
+            transaction_writer=False,
+            learning_session=True
+        )
+        self.transaction_writer = SessionOutputWriter(
+            self,
+            transaction_writer=True,
+            learning_session=True
+        )
+
+    def set_as_eval(self):
+        """Set the writers to write to eval directories."""
+        self.episode_av_reward_writer = SessionOutputWriter(
+            self,
+            transaction_writer=False,
+            learning_session=False
+        )
+        self.transaction_writer = SessionOutputWriter(
+            self,
+            transaction_writer=True,
+            learning_session=False
+        )
+        self.episode_count = 0
 
     def reset(self):
         """
@@ -267,12 +268,14 @@ class Primaite(Env):
         Returns:
              Environment observation space (reset)
         """
-        csv_data = self.episode_count, self.average_reward
-        self.csv_writer.writerow(csv_data)
+        if self.episode_count > 0:
+            csv_data = self.episode_count, self.average_reward
+            self.episode_av_reward_writer.write(csv_data)
 
         self.episode_count += 1
 
-        # Don't need to reset links, as they are cleared and recalculated every step
+        # Don't need to reset links, as they are cleared and recalculated every
+        # step
 
         # Clear the ACL
         self.init_acl()
@@ -303,12 +306,8 @@ class Primaite(Env):
              done: Indicates episode is complete if True
              step_info: Additional information relating to this step
         """
-        if self.step_count == 0:
-            _LOGGER.info(f"Episode: {str(self.episode_count)}")
-
         # TEMP
         done = False
-
         self.step_count += 1
         self.total_step_count += 1
 
@@ -321,13 +320,16 @@ class Primaite(Env):
 
         # Create a Transaction (metric) object for this step
         transaction = Transaction(
-            datetime.now(), self.agent_identifier, self.episode_count,
+            self.agent_identifier,
+            self.episode_count,
             self.step_count
         )
         # Load the initial observation space into the transaction
-        transaction.set_obs_space_pre(copy.deepcopy(self.env_obs))
+        transaction.obs_space_pre = copy.deepcopy(self.env_obs)
         # Load the action space into the transaction
-        transaction.set_action_space(copy.deepcopy(action))
+        transaction.action_space = copy.deepcopy(action)
+
+        initial_nodes = copy.deepcopy(self.nodes)
 
         # 1. Implement Blue Action
         self.interpret_action_and_apply(action)
@@ -381,7 +383,7 @@ class Primaite(Env):
 
         # 5. Calculate reward signal (for RL)
         reward = calculate_reward_function(
-            self.nodes_post_pol,
+            initial_nodes,
             self.nodes_post_red,
             self.nodes_reference,
             self.green_iers,
@@ -390,17 +392,22 @@ class Primaite(Env):
             self.step_count,
             self.training_config,
         )
-        _LOGGER.debug(f"    Step {self.step_count} Reward: {str(reward)}")
+        _LOGGER.debug(
+            f"Episode: {self.episode_count}, "
+            f"Step {self.step_count}, "
+            f"Reward: {reward}"
+        )
         self.total_reward += reward
         if self.step_count == self.episode_steps:
             self.average_reward = self.total_reward / self.step_count
-            if self.training_config.session_type == "EVALUATION":
+            if self.training_config.session_type is SessionType.EVAL:
                 # For evaluation, need to trigger the done value = True when
                 # step count is reached in order to prevent neverending episode
                 done = True
-            _LOGGER.info(f"  Average Reward: {str(self.average_reward)}")
+            _LOGGER.info(f"Episode: {self.episode_count}, "
+                         f"Average Reward: {self.average_reward}")
             # Load the reward into the transaction
-        transaction.set_reward(reward)
+        transaction.reward = reward
 
         # 6. Output Verbose
         # self.output_link_status()
@@ -408,28 +415,14 @@ class Primaite(Env):
         # 7. Update env_obs
         self.update_environent_obs()
         # Load the new observation space into the transaction
-        transaction.set_obs_space_post(copy.deepcopy(self.env_obs))
+        transaction.obs_space_post = copy.deepcopy(self.env_obs)
 
-        # 8. Add the transaction to the list of transactions
-        self.transaction_list.append(copy.deepcopy(transaction))
+        # Write transaction to file
+        self.transaction_writer.write(transaction)
 
         # Return
         return self.env_obs, reward, done, self.step_info
 
-    def close(self):
-        self.__close__()
-
-    def __close__(self):
-        """
-        Override close function
-        """
-        write_transaction_to_file(
-            self.transaction_list,
-            self.session_path,
-            self.timestamp_str
-        )
-        self.csv_file.close()
-
     def init_acl(self):
         """Initialise the Access Control List."""
         self.acl.remove_all_rules()
@@ -467,7 +460,7 @@ class Primaite(Env):
         ):  # Node actions in multdiscrete (array) from have len 4
             self.apply_actions_to_nodes(_action)
         else:
-            logging.error("Invalid action type found")
+            _LOGGER.error("Invalid action type found")
 
     def apply_actions_to_nodes(self, _action):
         """
diff --git a/src/primaite/environment/reward.py b/src/primaite/environment/reward.py
index 1a1a0770..00e45fa3 100644
--- a/src/primaite/environment/reward.py
+++ b/src/primaite/environment/reward.py
@@ -85,9 +85,6 @@ def calculate_reward_function(
             )
 
             if live_blocked and not reference_blocked:
-                _LOGGER.debug(
-                    f"Applying reward of {ier_reward} because IER {ier_key} is blocked"
-                )
                 reward_value += ier_reward
             elif live_blocked and reference_blocked:
                 _LOGGER.debug(
diff --git a/src/primaite/main.py b/src/primaite/main.py
index 5aba68ef..3c0f93b3 100644
--- a/src/primaite/main.py
+++ b/src/primaite/main.py
@@ -20,6 +20,7 @@ def run(training_config_path: Union[str, Path], lay_down_config_path: Union[str,
 
     session.setup()
     session.learn()
+    session.evaluate()
 
 
 if __name__ == "__main__":
diff --git a/src/primaite/setup/_package_data/primaite_config.yaml b/src/primaite/setup/_package_data/primaite_config.yaml
index 5d469ffe..1dd8775b 100644
--- a/src/primaite/setup/_package_data/primaite_config.yaml
+++ b/src/primaite/setup/_package_data/primaite_config.yaml
@@ -1,10 +1,11 @@
 # The main PrimAITE application config file
 
 # Logging
-log_level: INFO
-logger_format:
-  DEBUG: '%(asctime)s: %(message)s'
-  INFO: '%(asctime)s: %(message)s'
-  WARNING: '%(asctime)s::%(levelname)s::%(name)s::%(lineno)s::%(message)s'
-  ERROR: '%(asctime)s::%(levelname)s::%(name)s::%(lineno)s::%(message)s'
-  CRITICAL: '%(asctime)s::%(levelname)s::%(name)s::%(lineno)s::%(message)s'
+logging:
+  log_level: INFO
+  logger_format:
+    DEBUG: '%(asctime)s: %(message)s'
+    INFO: '%(asctime)s: %(message)s'
+    WARNING: '%(asctime)s::%(levelname)s::%(name)s::%(lineno)s::%(message)s'
+    ERROR: '%(asctime)s::%(levelname)s::%(name)s::%(lineno)s::%(message)s'
+    CRITICAL: '%(asctime)s::%(levelname)s::%(name)s::%(lineno)s::%(message)s'
diff --git a/src/primaite/transactions/transaction.py b/src/primaite/transactions/transaction.py
index a4ce48e3..6e5ba5f0 100644
--- a/src/primaite/transactions/transaction.py
+++ b/src/primaite/transactions/transaction.py
@@ -1,57 +1,115 @@
 # Crown Copyright (C) Dstl 2022. DEFCON 703. Shared in confidence.
 """The Transaction class."""
+from datetime import datetime
+from typing import List, Tuple
 
 
 class Transaction(object):
     """Transaction class."""
 
-    def __init__(self, _timestamp, _agent_identifier, _episode_number, _step_number):
+    def __init__(
+            self,
+            agent_identifier,
+            episode_number,
+            step_number
+    ):
         """
-        Init.
+        Transaction constructor.
 
-        Args:
-            _timestamp: The time this object was created
-            _agent_identifier: An identifier for the agent in use
-            _episode_number: The episode number
-            _step_number: The step number
+        :param agent_identifier: An identifier for the agent in use
+        :param episode_number: The episode number
+        :param step_number: The step number
         """
-        self.timestamp = _timestamp
-        self.agent_identifier = _agent_identifier
-        self.episode_number = _episode_number
-        self.step_number = _step_number
+        self.timestamp = datetime.now()
+        "The datetime of the transaction"
+        self.agent_identifier = agent_identifier
+        self.episode_number = episode_number
+        "The episode number"
+        self.step_number = step_number
+        "The step number"
+        self.obs_space_pre = None
+        "The observation space before any actions are taken"
+        self.obs_space_post = None
+        "The observation space after any actions are taken"
+        self.reward = None
+        "The reward value"
+        self.action_space = None
+        "The action space invoked by the agent"
 
-    def set_obs_space_pre(self, _obs_space_pre):
-        """
-        Sets the observation space (pre).
+    def as_csv_data(self) -> Tuple[List, List]:
+        if isinstance(self.action_space, int):
+            action_length = self.action_space
+        else:
+            action_length = self.action_space.size
+        obs_shape = self.obs_space_post.shape
+        obs_assets = self.obs_space_post.shape[0]
+        if len(obs_shape) == 1:
+            # A bit of a workaround but I think the way transactions are
+            # written will change soon
+            obs_features = 1
+        else:
+            obs_features = self.obs_space_post.shape[1]
 
-        Args:
-            _obs_space_pre: The observation space before any actions are taken
-        """
-        self.obs_space_pre = _obs_space_pre
+        # Create the action space headers array
+        action_header = []
+        for x in range(action_length):
+            action_header.append("AS_" + str(x))
 
-    def set_obs_space_post(self, _obs_space_post):
-        """
-        Sets the observation space (post).
+        # Create the observation space headers array
+        obs_header_initial = []
+        obs_header_new = []
+        for x in range(obs_assets):
+            for y in range(obs_features):
+                obs_header_initial.append("OSI_" + str(x) + "_" + str(y))
+                obs_header_new.append("OSN_" + str(x) + "_" + str(y))
 
-        Args:
-            _obs_space_post: The observation space after any actions are taken
-        """
-        self.obs_space_post = _obs_space_post
+        # Open up a csv file
+        header = ["Timestamp", "Episode", "Step", "Reward"]
+        header = header + action_header + obs_header_initial + obs_header_new
 
-    def set_reward(self, _reward):
-        """
-        Sets the reward.
+        row = [
+            str(self.timestamp),
+            str(self.episode_number),
+            str(self.step_number),
+            str(self.reward),
+        ]
+        row = (
+                row
+                + _turn_action_space_to_array(self.action_space)
+                + _turn_obs_space_to_array(self.obs_space_pre, obs_assets,
+                                           obs_features)
+                + _turn_obs_space_to_array(self.obs_space_post, obs_assets,
+                                           obs_features)
+        )
+        return header, row
 
-        Args:
-            _reward: The reward value
-        """
-        self.reward = _reward
 
-    def set_action_space(self, _action_space):
-        """
-        Sets the action space.
+def _turn_action_space_to_array(action_space) -> List[str]:
+    """
+    Turns action space into a string array so it can be saved to csv.
 
-        Args:
-            _action_space: The action space invoked by the agent
-        """
-        self.action_space = _action_space
+    :param action_space: The action space
+    :return: The action space as an array of strings
+    """
+    if isinstance(action_space, list):
+        return [str(i) for i in action_space]
+    else:
+        return [str(action_space)]
+
+
+def _turn_obs_space_to_array(obs_space, obs_assets, obs_features) -> List[str]:
+    """
+    Turns observation space into a string array so it can be saved to csv.
+
+    :param obs_space: The observation space
+    :param obs_assets: The number of assets (i.e. nodes or links) in the
+        observation space
+    :param obs_features: The number of features associated with the asset
+    :return: The observation space as an array of strings
+    """
+    return_array = []
+    for x in range(obs_assets):
+        for y in range(obs_features):
+            return_array.append(str(obs_space[x][y]))
+
+    return return_array
diff --git a/src/primaite/transactions/transactions_to_file.py b/src/primaite/transactions/transactions_to_file.py
deleted file mode 100644
index ed7a8f1c..00000000
--- a/src/primaite/transactions/transactions_to_file.py
+++ /dev/null
@@ -1,119 +0,0 @@
-# Crown Copyright (C) Dstl 2022. DEFCON 703. Shared in confidence.
-"""Writes the Transaction log list out to file for evaluation to utilse."""
-
-import csv
-from pathlib import Path
-
-import numpy as np
-
-from primaite import getLogger
-
-_LOGGER = getLogger(__name__)
-
-
-def turn_action_space_to_array(_action_space):
-    """
-    Turns action space into a string array so it can be saved to csv.
-
-    Args:
-        _action_space: The action space.
-    """
-    if isinstance(_action_space, list):
-        return [str(i) for i in _action_space]
-    else:
-        return [str(_action_space)]
-
-
-def turn_obs_space_to_array(_obs_space, _obs_assets, _obs_features):
-    """
-    Turns observation space into a string array so it can be saved to csv.
-
-    Args:
-        _obs_space: The observation space
-        _obs_assets: The number of assets (i.e. nodes or links) in the observation space
-        _obs_features: The number of features associated with the asset
-    """
-    return_array = []
-    for x in range(_obs_assets):
-        for y in range(_obs_features):
-            return_array.append(str(_obs_space[x][y]))
-
-    return return_array
-
-
-def write_transaction_to_file(transaction_list, session_path: Path, timestamp_str: str):
-    """
-    Writes transaction logs to file to support training evaluation.
-
-    :param transaction_list: The list of transactions from all steps and all
-        episodes.
-    :param session_path: The directory path the session is writing to.
-    :param timestamp_str: The session timestamp in the format:
-        <yyyy-mm-dd>_<hh-mm-ss>.
-    """
-    # Get the first transaction and use it to determine the makeup of the
-    # observation space and action space
-    # Label the obs space fields in csv as "OSI_1_1", "OSN_1_1" and action
-    # space as "AS_1"
-    # This will be tied into the PrimAITE Use Case so that they make sense
-
-    template_transation = transaction_list[0]
-    if isinstance(template_transation.action_space, int):
-        action_length = template_transation.action_space
-    else:
-        action_length = template_transation.action_space.size
-    obs_shape = template_transation.obs_space_post.shape
-    obs_assets = template_transation.obs_space_post.shape[0]
-    if len(obs_shape) == 1:
-        # bit of a workaround but I think the way transactions are written will change soon
-        obs_features = 1
-    else:
-        obs_features = template_transation.obs_space_post.shape[1]
-
-    # Create the action space headers array
-    action_header = []
-    for x in range(action_length):
-        action_header.append("AS_" + str(x))
-
-    # Create the observation space headers array
-    obs_header_initial = []
-    obs_header_new = []
-    for x in range(obs_assets):
-        for y in range(obs_features):
-            obs_header_initial.append("OSI_" + str(x) + "_" + str(y))
-            obs_header_new.append("OSN_" + str(x) + "_" + str(y))
-
-    # Open up a csv file
-    header = ["Timestamp", "Episode", "Step", "Reward"]
-    header = header + action_header + obs_header_initial + obs_header_new
-
-    try:
-        filename = session_path / f"all_transactions_{timestamp_str}.csv"
-        _LOGGER.debug(f"Saving transaction logs: {filename}")
-        csv_file = open(filename, "w", encoding="UTF8", newline="")
-        csv_writer = csv.writer(csv_file)
-        csv_writer.writerow(header)
-
-        for transaction in transaction_list:
-            csv_data = [
-                str(transaction.timestamp),
-                str(transaction.episode_number),
-                str(transaction.step_number),
-                str(transaction.reward),
-            ]
-            csv_data = (
-                csv_data
-                + turn_action_space_to_array(transaction.action_space)
-                + turn_obs_space_to_array(
-                    transaction.obs_space_pre, obs_assets, obs_features
-                )
-                + turn_obs_space_to_array(
-                    transaction.obs_space_post, obs_assets, obs_features
-                )
-            )
-            csv_writer.writerow(csv_data)
-
-        csv_file.close()
-        _LOGGER.debug("Finished writing transactions")
-    except Exception:
-        _LOGGER.error("Could not save the transaction file", exc_info=True)
diff --git a/src/primaite/utils/session_output_writer.py b/src/primaite/utils/session_output_writer.py
new file mode 100644
index 00000000..308e1fb3
--- /dev/null
+++ b/src/primaite/utils/session_output_writer.py
@@ -0,0 +1,73 @@
+import csv
+from logging import Logger
+from typing import List, Final, IO, Union, Tuple
+from typing import TYPE_CHECKING
+
+from primaite import getLogger
+from primaite.transactions.transaction import Transaction
+
+if TYPE_CHECKING:
+    from primaite.environment.primaite_env import Primaite
+
+_LOGGER: Logger = getLogger(__name__)
+
+
+class SessionOutputWriter:
+    _AV_REWARD_PER_EPISODE_HEADER: Final[List[str]] = [
+        "Episode", "Average Reward"
+    ]
+
+    def __init__(
+            self,
+            env: "Primaite",
+            transaction_writer: bool = False,
+            learning_session: bool = True
+    ):
+        self._env = env
+        self.transaction_writer = transaction_writer
+        self.learning_session = learning_session
+
+        if self.transaction_writer:
+            fn = f"all_transactions_{self._env.timestamp_str}.csv"
+        else:
+            fn = f"average_reward_per_episode_{self._env.timestamp_str}.csv"
+
+        if self.learning_session:
+            self._csv_file_path = self._env.session_path / "learning" / fn
+        else:
+            self._csv_file_path = self._env.session_path / "evaluation" / fn
+
+        self._csv_file_path.parent.mkdir(exist_ok=True, parents=True)
+
+        self._csv_file = None
+        self._csv_writer = None
+
+        self._first_write: bool = True
+
+    def _init_csv_writer(self):
+        self._csv_file = open(
+            self._csv_file_path, "w", encoding="UTF8", newline=""
+        )
+
+        self._csv_writer = csv.writer(self._csv_file)
+
+    def __del__(self):
+        if self._csv_file:
+            self._csv_file.close()
+            _LOGGER.info(f"Finished writing file: {self._csv_file_path}")
+
+    def write(
+            self,
+            data: Union[Tuple, Transaction]
+    ):
+        if isinstance(data, Transaction):
+            header, data = data.as_csv_data()
+        else:
+            header = self._AV_REWARD_PER_EPISODE_HEADER
+
+        if self._first_write:
+            self._init_csv_writer()
+            self._csv_writer.writerow(header)
+            self._first_write = False
+
+        self._csv_writer.writerow(data)
diff --git a/tests/conftest.py b/tests/conftest.py
index 1bad5db0..945d23f0 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -37,7 +37,6 @@ def _get_primaite_env_from_config(
     env = Primaite(
         training_config_path=training_config_path,
         lay_down_config_path=lay_down_config_path,
-        transaction_list=[],
         session_path=session_path,
         timestamp_str=timestamp_str,
     )