A cantilever gantry crane has girders that:

A cantilever gantry crane is specifically designed with girders that extend transversely beyond the crane runway, which allows for greater flexibility in lifting and moving loads, particularly in areas where operational space is limited. This design enables the crane to access areas beyond the immediate path of the crane's track, enhancing its capability to lift and transport materials effectively.

The horizontal extension of the girders provides a wider span and can accommodate various loads, increasing the crane's utility. This distinctive feature is what sets cantilever gantry cranes apart from other crane designs where the girders may be flush with the runway or only extend on one side. Additionally, modular designs that allow for girder adjustments are not characteristic of cantilever gantry cranes but are often found in other types of crane systems. Thus, the defining characteristic of the girders extending transversely beyond the runway directly contributes to a cantilever gantry crane's functionality and versatility in various applications.