Containers are respectively loaded onto and delivered from two trolleys of a single crane at pick-up and delivery locations by guided travel of one of the trolleys along a fixed travel path on a boom between the delivery location at one end of the boom and a turn-table platform of the crane on which a pair of angularly related track paths are established for alternative alignment with the fixed travel path on the boom, to accommodate transfer of the trolleys between such fixed travel path and either one of the track paths on the platform.