At the World Trade Center, 80-ft below street level beneath future Tower’s 3 and 4 sit a series of United Technologies 400KW fuel cells, the latest in energy cogeneration modular powerplants. These 30-ton units needed to be relocated from inside Tower 4 to their final resting places in one of Tower 3’s numerous mechanical rooms. The process involved overcoming a 4-ft drop in elevation where the two building footprints’ met.  Overhead clearance was less than 24-in. A deck and jacking system was developed and implemented that allowed the rigging process to repeated quickly and safely. The units were moved, one by one, to the new floor and set level by our master riggers.