This minor group comprises machinery and transportation equipment mechanics (except motor vehicles), including construction millwrights and industrial mechanics; heavy-duty equipment mechanics; heating, refrigeration and air conditioning mechanics; railway carmen/women; aircraft mechanics and aircraft inspectors; machine fitters; and elevator constructors and mechanics. They are employed by millwrighting contractors, manufacturing plants, utilities and other industrial establishments; heavy equipment dealers, rental and service establishments and companies that own and operate heavy equipment; refrigeration and air conditioning installation contractors, food wholesalers, engineering firms and retail and servicing establishments; railway transport companies and urban transit systems; aircraft manufacturing, maintenance, repair and overhaul establishments, and airlines and other aircraft operators; industrial machinery and transportation equipment manufacturing industries; and elevator construction and maintenance companies.