diff --git a/src/articulated_vehicles.h b/src/articulated_vehicles.h
--- a/src/articulated_vehicles.h
+++ b/src/articulated_vehicles.h
@@ -23,6 +23,7 @@ uint32 GetUnionOfArticulatedRefitMasks(E
 uint32 GetIntersectionOfArticulatedRefitMasks(EngineID engine, bool include_initial_cargo_type);
 bool IsArticulatedVehicleCarryingDifferentCargoes(const Vehicle *v, CargoID *cargo_type);
 bool IsArticulatedVehicleRefittable(EngineID engine);
+bool IsArticulatedEngine(EngineID engine_type);
 void CheckConsistencyOfArticulatedVehicle(const Vehicle *v);