ESSENTIAL SERVICES - Shall mean underground gas, electrical, telephone, telegraph, steam or water transmission or distribution systems, including mains, drains, sewers, pipes, conduits, cables; and including normal above ground appurtenances such as fire alarm boxes, police call boxes, light standards, poles, traffic signals, hydrants, and other similar equipment and accessories in connection therewith, reasonably necessary for the furnishing of adequate service by public utilities or municipal or other governmental agencies or for the public health or safety or general welfare.