1. Double girder gantry Crane is widely used together with winch or trolley for lifting device. 2. It is a medium and heavy size crane which travels in track. 3. Its proper lifting weight is 5 to 75 tons,and proper span is 18 to 35 meters. 4. Its proper working temperature is -20--+40 centigrade. 5 .This kind of crane is composed of main beam, support legs, crane traveling organ, trolley, electric equipment, strong lifting winch. 6. This product is a regular crane widely used in workshop, storage, port and hydroelectric power station and some other outdoor place, where it has a high frequency or more lifting times. 7. Gantry lift has two controlliing methods namely ground controlling and cabin controlling. 8. Power is supplied by cable or slide wire. 9. It is prohibited for lifting melt metal, flammable, explosive, corrosion, overloading, dust and other dangerous operations. 10.Double girder gantry crane have A type, U type. U type is designed for container lifting. It could be designed with cantilever or not. 11.The crane with three working class: A5,A6,A7.