The time is 3 a.m. The place is a dangerous subterranean world rich with obstacles and eerie shadows 65 feet below the streets of Lower Manhattan. Invisible to all eyes above, workers toil to raise a new skyscraper where the towers fell.
One morning last week, guided by the bare bulbs of construction lights, 15 hard hats picked their way through the World Trade Center pit. They were ever mindful of the threat of the errant PATH train, and never unaware of the proximity of the 600-volt third rail.
Their effort is not only risky but arduous and precise. This preliminary work is essential if the $2 billion Freedom Tower is to soar 1,776 feet above Manhattan by 2011.
The work quietly began on March 28, and was proceeding unnoticed until an equipment convoy from a subcontractor arrived nearly a month later, prompting Gov. George E. Pataki and the builder Larry A. Silverstein to announce the beginning of construction, 21 months after the tower's cornerstone had been laid.
Yet for all the fanfare and squabbling over this gargantuan office building — which is also a political and architectural statement — the work of these underground crews could not seem more humbly utilitarian.
Before the tower's foundation work can begin, engineers and construction workers are relocating the train signaling system for the World Trade Center PATH station, the power system supplying electrical current to the tracks, the water pipes that lead to fire stanchions and the steel conduit providing compressed air to operate the track switches.
If left in place, these utilities would block the Freedom Tower's massive steel support columns and their concrete footings.
"This is the beginning of a five-year process, the first of many, many steps, as we build block upon block upon block in a very tight time frame," Mr. Silverstein said in an interview.
Under a new rebuilding plan put in place last month, he will no longer serve as the developer or control the tower's 2.6 million square feet of office space. Instead, he will be paid a 1 percent fee to build it under the supervision of the Port Authority of New York and New Jersey, and then turn over the keys to the agency, which will lease, manage and own it.
"This will be the icon of the New York skyline and will reaffirm our resilience and resolve," Mr. Silverstein commented, "and it absolutely must be built." And so the work goes on, long before dawn, in times of sparse ridership, when trains can be diverted from the site.
"It's a chess game," said Gary Cohen, a senior project manager for Tishman Construction, which is overseeing the work.
The access time is limited by a tight construction schedule: weekdays from 1 to 5 a.m. and weekends from 1 a.m. on Saturday until 5 a.m. on Monday.
And so, shortly after 1 a.m. last Thursday, Vin Caposello, a power railman with PATH, carefully touched the prongs of a voltage tester to the third rail to verify that it had been cut off in the work area. "But our rule is that you always treat the third rail as if it's live," Mr. Caposello said, "since touching it is most likely fatal."
Then, in a claustrophobic area under the former trade center parking garage, workers for Tishman and its subcontractor, Petrocelli Electric, began gingerly stepping over the third rail. At the work space, they began to put the new utilities in place, using saws, jackhammers and drills. The installation of the new system and the deactivation of the old is expected to be finished in August.
During this time, the all-night PATH trains from New Jersey are arriving through the south tunnel under the Hudson, on Track 4, and leaving on the same track, instead of making their customary loop through the return tunnel. This affords workers safe access to the northern tracks.
Nevertheless, "we always assume a train could come, because it has," said Brian E. Lyons, the early-morning project manager for Tishman. A few mornings ago, he said, an unannounced maintenance train was stopped before it reached the workers.
Anthony Fedor, a safety manager for Tishman at the work site, said, "Being here is definitely a challenge, but it's a privilege to be doing this, knowing what happened here."
After the utilities have been relocated, the next task will be to thread the tower's colossal steel support columns through the spaghetti of tracks. Column footings will be placed in 19 locations, and steel will be driven down as much as 15 feet into the bedrock.
In engineering-speak, this is called "a customized footings package." Usually, support columns are positioned in a symmetrical grid, but the Freedom Tower locations are oddly positioned. "They are shaped and rotated to fit the track geology," Mr. Cohen said, to keep from establishing support pillars, say, in the path of a hurtling subway car.
Concrete is to rise to the street in April 2008.
"Everyone says that there's no work going on at the Freedom Tower, so I ask you — what am I and this crew doing every night?" Mr. Lyons asked with a laugh.
He proposed to his wife, Lori, on the observation deck of the south tower in 1988. He walked off his construction job in Midtown on Sept. 11, 2001, to volunteer in recovery operations at ground zero. He never went back. Mr. Lyons, 46, worked at the site until he found the fire tools, but not the remains, of his 32-year-old brother, Michael, a firefighter who died in the south tower.
Since then, Mr. Lyons has worked to help build the temporary PATH station and to rebuild Mr. Silverstein's 7 World Trade Center at Vesey Street.
Outside the tunnel, where no utilities need to be moved, workers have started digging down to bedrock to make way for the Freedom Tower support columns.
"It's such a satisfying feeling, working down here at night," Mr. Lyons said, standing in the Freedom Tower footprint, outlined in the glow of the giant banks of halogen stadium lights that illuminate the site. "Out in the pit, it's so very quiet. It's a spiritual place. It's an emotional thing for me."