The single group gantry crane has a simple structure, easy manufacturing and installation, and a small self weight. The main beam is mostly a skewed rail box frame structure. Compared with double girder gantry cranes, the overall stiffness is weaker. The L-shaped design is easy to manufacture and install, with good stress conditions and relatively small weight. However, the space for lifting goods through the support legs is relatively small. The C-shaped legs are designed to be inclined or curved, with the aim of providing ample lateral space for goods to pass smoothly through the legs.Therefore, when the lifting capacity Q is ≤ 50t and the span S is ≤ 35m, this form can be used. The single girder gantry crane has two types of gantry legs: L-shaped and C-shaped.