ZZHZ(zzhz.com) has very rich experience of producing the large duty gantry crane.
1200t gantry crane is the largest tonnage crane for bridge construction of highway and railway in China.  It is designed, manufactured and installed by our company independently.
a. the structure adopts structure with double box girder type’s frame and double rigid legs. It can meet strength, rigidity and stability of the large ton gantry crane.
b. double lifting trolleys can travel together. The two lifting trolleys are connected by pull rod and put on one set gantry crane. The transverse distance of lifting point can be adjusted by adjusting hr length of pull rod.
c. the cart travel mechanism adopts double rails and three layer equilibrium which can adapt the change of longitudinal and transverse slope. The cart travel mechanism can turn 90°with rails.
d.the trolleys of two gantry cranes can meet the requirements of force which can protect the concrete beam 
e、each gantry crane is equipped with generating set with internal combustion which can supply power by itself.
 f、the electrical system adopts PLC control technology with frequency conversion, touch screen display control, remote control, safety protection and fault detection etc. The system uses wlan communication module to make two gantry crane work together to lift beam. 
 g、lifting mechanism, cart traveling mechanism and trolley traveling mechanism adopt AC variable frequency motor. Under the control of electrical system, according to load, the motor can change the speed continuously, start softly, stop softly and avoid impacting.