Essential services. The erection, construction, alteration, use and maintenance by municipal or governmental agencies and public utilities or public service corporations of such facilities as are reasonably necessary for the furnishing of adequate service by such agencies, utilities or public service corporations or for public health, safety or general welfare, including underground or overhead electrical, gas, steam or water transposal systems, including poles, wires, lines, mains, drains, sewers, conduits, cables, fire alarm boxes, police call boxes, traffic signals, hydrants, gas regulator and measuring devices, including the structures in which they are housed, and other similar equipment and accessories in connection therewith, provided that any structure housing such equipment shall conform to the general character as to appearance and structural material of the other structures within the district, and further provided that such structure shall not include the storage of vehicles or equipment necessary to the normal maintenance, repair or installation for any utility. Structures shall not be permitted for the housing of transformers, pumps and similar equipment that cause any noise, odor, smoke or other hazardous effect. The installation of these "essential services" shall be permitted without the requirement of a public hearing by the Public Utility Commission, the City Council or the Zoning Hearing Board.