I have an object called TransportMaster, with concrete implementations X_TransportMaster, Y_TransportMaster, Z_TransportMaster. The application instance may contain any number of any mixture of these objects, and they may be created and destroyed at any time by the user. Their use within the application is also subject to the user's whims.

Why would a TransportMasterManager, which provides factory methods, enumerations, a collection of the current set of TM's, and knowledge of the current user choice for which TM's is being used for what, have "no place" in this design?