Steel framing for the 104-story office tower is complete to the roof, at a height of 1,368 ft. Crews currently are building a five-level steel "dog house," a temporary rooftop structure for the tower cranes that will allow crews to finish concrete work.

Workers are on course to begin lifting pieces of the 408-ft-tall spire, recently redesigned with no cladding, early next year. When complete, the building is expected to rank as the tallest in the Western Hemisphere.

Also early next year, steel erection is set to begin for the iconic WTC Transportation Hub, which Plate says is on course for its 2015 finish. Permanent power is turned on for the entire complex. The site's vehicle screening center is on course for completion in two years.

Outside the site, the $1.4-billion Fulton Center project, which will reorganize connections between 10 subway lines and link commuters, via a 365-ft-long underpass, to the WTC Transportation Hub, is 75% complete, says Michael Horodniceanu, president of the Metropolitan Transportation Authority's Capital Construction Co. The project is slightly ahead of schedule and on budget. It is expected to be finished in June 2014, but the actual link to the WTC hub will not be made until 2015.