NEW YORK (AP) - The hum of massive mobile generators, boilers and pumps emerges blocks from Manhattan's Financial District and turns into a steady din south of Wall Street - the now-familiar sound of an area laboring to recover from Superstorm Sandy.
Other parts of the city have gotten mayoral visits and media attention after the Oct. 29 storm killed dozens of residents and tore apart homes in coastal neighborhoods. Less obvious were the millions upon million gallons of sea water that wreaked havoc on subterranean electrical panels and other internal infrastructure throughout lower Manhattan, making them unusable even after power was restored to the area.
"There were waves on Wall Street, and it all ended up here," Mike Lahm, a building engineer who rode out the storm at 120 Wall Street, said during a recent tour of the skyscraper's basement.
Nearly a month later, some of the high-rises that are home to investment banks, large law firms and luxury apartments have bounced back quickly. But others buildings remain eerily dark and vacant.
Landlords have warned full power won't be back for weeks, if not months, leaving businesses and residents displaced and uncertain about when - and even whether - they'll return. JP Morgan Chase, the Daily News and the American Civil Liberties Union are among tenants still operating in satellite locations after getting washed out of their headquarters in lower Manhattan.
Heavy flooding also hit a complex of multimillion-dollar apartments along the Hudson River, whose well-heeled owners - reportedly including Gwyneth Paltrow and Meryl Streep - could quietly retreat to second or third homes on higher and drier ground.
"What you're looking at here is a mass exodus," downtown resident Gail Strum said as she retrieved some files and other belongings from a rental apartment building that's still without power. "It feels like there's no coming back."
On paper, Strum's assessment sounds too pessimistic. The city Buildings Department declared only nine buildings in lower Manhattan unsafe because of structural damage from the storm, and the power company, Consolidated Edison, says all buildings citywide had access to electricity and steam power by Nov. 15.
A real estate consulting firm that's tracking the lower Manhattan recovery, Jones Lang LaSalle, says 49 of the 183 office buildings in the business district were closed because of mechanical failures. By the latest count, at least half were back in full operation, even if it has meant relying on temporary power. More are expected to follow.
"We see that as a very healthy pace," said John Wheeler, a Jones Lang LaSalle executive.
One success story was 120 Wall Street, a 600,000-square-foot, 34-story skyscraper built near the East River that's home to nonprofits such as the National Urban League, the United Negro College Fund and the Eye-Bank for Sight Restoration.
Even before Sandy hit, landlord Silverstein Properties got ahead of a scramble for recovery resources by securing portable diesel generators each capable of providing 2 megawatts of power. Afterward, the building brought in its own fuel tanker from Pennsylvania - and a security team from Florida to guard it - so it could keep the generators going during the gas crunch.
Using a mix of generator power and restored Con Ed service, engineers had the elevators, lights and heat up and running by mid-November.
To the tenants, "It's as if the building's operating normally," said Jeremy Moss, a vice president with Silverstein Properties.
What tenants don't see in the bowels of 120 Wall Street is a thicket of temporary, exposed wiring that runs everywhere. The warning "LIVE WIRE. KEEP OUT" is spray-painted in red on the door of a room housing switches, fuses or circuit breakers after it was submerged. The air is clammy and musty - "the smell of the East River," said Lahm, the building engineer.
Fearing the East River might one day try again to meet the Hudson, 120 Wall Street and other buildings are facing an even bigger, more expensive job: Moving critical infrastructure to higher floors or even roofs.
"We're going to need to relocate equipment so history doesn't repeat itself," Moss said.
Farther uptown, NYU Langone Medical Center and Bellevue Hospital Center had put generators on high floors where they could be protected in a flood. But they still suffered failures with Sandy, apparently because other critical components of the backup power system, such as fuel pumps and tanks, remained in basements just a block from the East River.
While 120 Wall Street enjoys a degree of normalcy, other newer and taller glass towers around it remain shut as teams of contractors and workers struggle to restore power, phone and other services. Tractor-trailers providing emergency services such as "microbial remediation" crowd the streets. Cabs are few.
Fire engines became a part of the mix on Friday with the report of a fire in the basement of another vacated office building at 55 Water St. - the address