According to the different structure of main beam, it can be divided into box beam and truss. Generally, box structure is adopted. Heavy Duty 20 Ton Gantry Crane. Parameters: Lifting Capacity: 5t~500t. Span Length: 18~35m. Lifting Height: 6~18m. Lifting Speed: 1.5~11.5m/min. Trolley Traveling Speed: 10~40.1m/min.