How to feed girder to the launching girder?

After two tires carrier carry precast girder from the precast yard into the rear part main girder of launching girder, use the lifting trolley to lift, carry and drop girder.

As carrying girder, the two girder carriers move at the same speed, after the front trolley lifts one end of girder, it moves with rear girder carrier at the speed of 5.12m/min until the rear trolley lifts the girder, then the two trolleys lift and carry the girder at the speed of 5.12m/min.

At the time it finishes girder feeding, two carriers return to the precast yard for next round girder carrying.