A new platform over Penn Station's rail yard was hailed Tuesday as the answer to a public space shortage in crowded Manhattan and will become a grassy oasis linked to a residential and commercial development.

More than 200 construction, ironworkers, electricians and laborers were recognized for their roles in completing the deck that covers Penn Station's approach area, used by Long Island Rail Road, Amtrak and NJ Transit trains.

The Brookfield Manhattan West project is one of several new skyscraper developments being built on the once-desolate Hudson River waterfront in midtown. The $4.5 billion project will create a 2-acre park plaza with garden landscaping and seating at 33rd Street and Ninth Avenue.

The deck design was lauded by construction leaders as a solution to the borough's space crunch.

"This is a benchmark where we can learn. We are adding new land to Manhattan with this platform," said Al Fazio, Amtrak deputy chief engineer at a news conference Tuesday marking the completion of the concrete platform.

"This is a new neighborhood for workers, tourists and residents," said Fazio of the project that includes a 5-acre development with two 60-plus story high-rises expected to be completed by 2018. The project will also include a five-star hotel, restaurants and cafes with access to the public plaza.

The new deck was no easy feat. Workers had to dig 65 feet below street level and pour 9,600 cubic yards of concrete.

A $7 million machine called the "The Launcher" was especially designed and built to lift and place 16, 56,000-ton concrete bridge segments to build the platform.

"I was stressing cables to reinforce the spans," said ironworker Adriana Falcon, 36, of Franklin Square. "We had to meld them together with grout and glue."

Falcon, a former legal secretary and mother of two, said working on the project "was a once-in-a-lifetime opportunity. It was wonderful. I can now say to my children, 'Look at what your mother helped build.' This makes me feel proud."

Joseph Byrne, vice president and operations manager for Turner Construction Co., said, "This was a 24-7-day operation." He said at least 120 workers were on each shift, which enabled the one-year completion of the platform.

"This construction is happening in Toronto, Florida . . . anywhere where there are rail transportation yards that can be built over," Byrne said.