NEW YORK - It was once a gritty stretch of Manhattan known for rail yards, warehouses and aging industrial buildings, so desolate it was dubbed "The Wild, Wild West."
Now, one of the nation's biggest private construction projects is transforming a stretch of Manhattan's west side into a cluster of 20 new buildings - 17 of them high-rises - so tightly packed that it has earned a new, not always complimentary, nickname: "Hong Kong on the Hudson."
"This is going to be the new heart of New York," says Michael Samuelian, a project manager for the $20 billion Hudson Yards - a joint venture of Related Companies and Oxford Properties Group.
This development and the adjacent $4.5 billion Manhattan West complex comprise the city's most ambitious private real estate ventures since Rockefeller Center went up in the 1930s.
When fully completed in 2024, the two projects will offer more than 22 million square feet of space, including about 6,000 residential units - more footage than the rebuilt World Trade Center in lower Manhattan.
That is being accomplished, in part, through a feat of engineering: the construction of massive concrete platforms that allow the buildings to rise above and around active railroad tracks and rail yards. Amtrak and New Jersey Transit trains will keep running from New Jersey and other locations to Penn Station, used by about 700,000 people daily.
"This is what keeps me awake at night," says Dennis Friedrich, CEO of Manhattan West developer Brookfield Office Properties, as he stands by "The Launcher" - a $7 million, Italian-made hoisting machine created to lift 16 bridge-like concrete spans into place for the $300 million platform.
Each of the 240-foot spans - weighing about 2,400 tons, or the equivalent of 187 city buses - is inched into place in the middle of the night when train traffic is sparse.
Construction on Manhattan West's first, 65-story office tower will start after the platform is finished by year's end. Hudson Yards' wider platform relies on more traditional technology, requiring 253 columns to hold it up.
While the platforms are strong enough to support the weight of newly planned parklands and art-filled public spaces, the new high-rises themselves will rest on load-bearing steel columns planted into Manhattan bedrock.
The plan for Hudson Yards, occupying an area between 30th and 34th streets bordered by Tenth Avenue and the West Side Highway, features 16 buildings - 14 of them skyscrapers.
The first, 52-story tower rising over the rail yards is expected to open in 2015, anchored by the Coach luxury retailer with tenants including L'Oreal USA and German software giant SAP.
Work also has begun on Hudson Yards' tallest building - an 80-story skyscraper with an observation deck higher than the Empire State Building. It will be home to the corporate headquarters of Time Warner by 2019.
Manhattan West fills the block between Tenth and Ninth avenues with three towers - two more than 60 stories - a public plaza and walkway, shops, garages and a hotel. Tenants have yet to be announced.
Squeezed in-between the budding complexes is a nearly half-century-old, pyramid-shaped building that Brookfield purchased as part of Manhattan West. The 16-story building, which houses the world headquarters of The Associated Press among other companies, is to undergo a $200 million renovation with glass floor-to-ceiling exteriors by 2016.
New York University urban planner Mitchell Moss says the developments accelerate a shift of the city's high-end commercial heart away from the traditional stronghold of midtown Manhattan surrounding Rockefeller Center.
"They reflect New York's new economic center of gravity, shifting to the west and south all the way down to the World Trade Center," Moss says.
The neighborhood popularly called Hell's Kitchen to the east and Chelsea to the south had briefly been considered as the site of a proposed football stadium for the Jets meant to help win the city the 2012 Olympics. But those plans fell apart when New York lost the bid to London.
Even before the latest construction work, the area had seen something of a rebirth with its former elevated freight tracks transformed into the popular High Line park.
Some who live nearby are skeptical of what lies ahead.
"Something was going to be built over the rail yards - that was inevitable - and this would have been a nice opportunity to do something for the community," says resident Ann Warren, who owns a neighborhood cupcake bakery and was forced out of her apartment building on West 35th Street by eminent domain. "But all the developers want is to make money."