diff --git a/vehicle.h b/vehicle.h
--- a/vehicle.h
+++ b/vehicle.h
@@ -318,6 +318,7 @@ bool VehicleNeedsService(const Vehicle *
 uint GenerateVehicleSortList(const Vehicle*** sort_list, uint16 *length_of_array, byte type, PlayerID owner, StationID station, OrderID order, uint16 depot_airport_index, uint16 window_type);
 void BuildDepotVehicleList(byte type, TileIndex tile, Vehicle ***engine_list, uint16 *engine_list_length, uint16 *engine_count, Vehicle ***wagon_list, uint16 *wagon_list_length, uint16 *wagon_count);
 int32 SendAllVehiclesToDepot(byte type, uint32 flags, bool service, PlayerID owner, uint16 vlw_flag, uint32 id);
+bool IsVehicleInDepot(const Vehicle *v);
 void VehicleEnterDepot(Vehicle *v);
 
 /* Flags to add to p2 for goto depot commands */