A fabrication assembly for automated metal fabrication on an elongate metal workpiece includes: a track; a set of rotator assemblies on one side of the track configured to rotate a received workpiece; at least one fabrication robot movable along the track and configured to perform metal fabrication on the workpiece received by the set of rotator assemblies within a fabrication operational range; a set of trolleys movable along the same track and configured to receive the workpiece thereon, the fabrication assembly being configured to transfer the workpiece between the set of trolleys and the set of rotator assemblies in a horizontal direction transverse to the track within a workpiece transfer range that overlaps with the fabrication operational range. To accommodate the overlap, the at least one fabrication robot may be movable to outside the workpiece transfer range, and the set of trolleys may be movable to outside the fabrication operational range.