A general-purpose gantry crane, also known as a gantry crane or a portal crane, is a large lifting machine used for loading and unloading goods and materials. It has a bridge structure supported by two parallel tracks, on which a crane that can move along the tracks is mounted. This type of crane is suitable for ports, freight yards, workshops and other places. Because of its sturdy structure and large span, it can cover a large operating range and is widely used in heavy object handling operations.