diff --git a/workshop/__init__.py b/workshop/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/workshop/routes.py b/workshop/routes.py
new file mode 100644
index 0000000..cdd015a
--- /dev/null
+++ b/workshop/routes.py
@@ -0,0 +1,73 @@
+"""
+Definitions:
+
+- Feeder branch: A branch that connects a substation to a distribution network.
+- Route: A path of nodes with a single feeder branch.
+
+
+"""
+
+from power_grid_model_ds import Grid
+from power_grid_model_ds._core.model.arrays import LineArray, NodeArray
+
+# NodeArray.station_name?
+
+
+class NoCandidateNodesError(Exception):
+    """Exception raised when no candidate nodes are found for a new substation."""
+
+
+def build_new_substation(grid: Grid, location: tuple[float, float]) -> None:
+    """Build a new substation at the given location.
+
+    (Create a substation node at the given location)
+    """
+
+
+def get_all_routes(grid: Grid, substation_node: NodeArray) -> list[NodeArray]:
+    """Get all routes that originate from a given substation node."""
+
+
+def transfer_routes(grid: Grid, old_substation: NodeArray, new_substation: NodeArray) -> None:
+    """Migrate a subset of the routes of the old substation to the new substation.
+    Each route can be migrated fully or partially.
+
+    """
+    routes = get_all_routes(grid, old_substation)
+    for route in routes:
+        try:
+            connection_point = find_connection_point(route, old_substation, new_substation)
+        except NoCandidateNodesError:
+            continue
+
+        connect_to_route(grid, route, new_substation)
+
+
+def find_connection_point(route: NodeArray, old_substation: NodeArray, new_substation: NodeArray) -> NodeArray:
+    """Calculate the connection point for the new route.
+    This should be the geographically closest node to the new substation.
+
+    Should raise NoCandidateNodesError if all nodes in the route are geographically closer to the old substation.
+    """
+
+
+def connect_to_route(grid: Grid, connection_point: NodeArray, new_substation: NodeArray) -> None:
+    """Connect the new substation node to the connection point.
+
+    1. Create a new line that connects the two nodes
+    2. Deactivate the line that connects the connection point to the old substation
+    """
+
+
+def optimize_route_transfer(grid: Grid, connection_point: NodeArray) -> None:
+    """Attempt to optimize the route transfer moving the naturally open point (NOP) upstream towards the old substation.
+    This way, the new substation will take over more nodes of the original route.
+
+    Note that a node cannot be taken over if that results in a capacity issue on the grid.
+    """
+
+
+def check_for_capacity_issues(grid: Grid) -> tuple[NodeArray, LineArray]:
+    """Check for capacity issues on the grid.
+    Return the nodes and lines that with capacity issues.
+    """