Goliath Cranes or Gantry Crane are adapted to applications where overhead runways would be not possible, costly to erect and difficult to maintain in alignment. Where the installation is only temporary a gantry crane can be moved to a new location with less trouble or expenses than an overhead crane and its runway.
Also it is comparatively easy and inexpensive to extend the length of the runway and thus increase the working area of the crane. Most goliath crane/ gantry crane installations are outdoors applications.