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The double girder overhead crane is also called bridge crane, it is the crane with a hoist traveling along the bridge between two parallel runways.
Overhead crane are designed to meet the industrial requirements from light to heavy, covering all parts of the manufacturing area and process.
link:http://www.sinokocrane.com/p-1365/Double-Girder-Wire-Rope-Hoist-Overhead-Crane.html
Double Girder Wire Rope Hoist Overhead Crane