diff --git a/src/vehicle_gui.h b/src/vehicle_gui.h
--- a/src/vehicle_gui.h
+++ b/src/vehicle_gui.h
@@ -15,12 +15,6 @@
 void DrawVehicleProfitButton(const Vehicle *v, int x, int y);
 void ShowVehicleRefitWindow(const Vehicle *v, VehicleOrderID order);
 
-/* sorter stuff */
-void RebuildVehicleLists();
-void ResortVehicleLists();
-void SortVehicleList(vehiclelist_d *vl);
-void BuildVehicleList(vehiclelist_d *vl, PlayerID owner, uint16 index, uint16 window_type);
-
 #define PERIODIC_RESORT_DAYS 10
 
 extern const StringID _vehicle_sort_listing[];
@@ -69,7 +63,7 @@ static inline bool ValidVLWFlags(uint16 
 	return (flags == VLW_STANDARD || flags == VLW_SHARED_ORDERS || flags == VLW_STATION_LIST || flags == VLW_DEPOT_LIST || flags == VLW_GROUP_LIST);
 }
 
-void PlayerVehWndProc(Window *w, WindowEvent *e);
+void PlayerVehWndProc(Window *w, struct WindowEvent *e);
 
 int DrawVehiclePurchaseInfo(int x, int y, uint w, EngineID engine_number);
 
@@ -136,6 +130,29 @@ static inline WindowClass GetWindowClass
 /* Unified window procedure */
 void ShowVehicleViewWindow(const Vehicle *v);
 
-Vehicle *CheckClickOnVehicle(const ViewPort *vp, int x, int y);
+Vehicle *CheckClickOnVehicle(const struct ViewPort *vp, int x, int y);
+
+typedef GUIList<const Vehicle*> GUIVehicleList;
+
+struct vehiclelist_d {
+	GUIVehicleList vehicles;  ///< The list of vehicles
+	Listing *sorting;         ///< Pointer to the vehicle type related sorting.
+	VehicleType vehicle_type; ///< The vehicle type that is sorted
+};
+
+struct Sorting {
+	Listing aircraft;
+	Listing roadveh;
+	Listing ship;
+	Listing train;
+};
+
+extern Sorting _sorting;
+
+/* sorter stuff */
+void RebuildVehicleLists();
+void ResortVehicleLists();
+void SortVehicleList(vehiclelist_d *vl);
+void BuildVehicleList(vehiclelist_d *vl, PlayerID owner, uint16 index, uint16 window_type);
 
 #endif /* VEHICLE_GUI_H */