ESSENTIAL SERVICES — Shall mean underground gas, electrical, telephone, telegraph, cable T.V., steam or water transmission or distributor systems, including mains, drains, sewers, pipes, conduits and 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 herewith, reasonably necessary for the furnishing of adequate service by public utilities or municipal or government agencies or for the public health or safety or general welfare.