With the success of the High Line serving as a blueprint for what could someday be the Lowline, the city is moving forward on plans to convert a long-vacant underground space in a subway station into a park. NY1's Jose Martinez filed the following report.

It's become hugely popular: an old elevated railroad line transformed into an urban oasis.

A long-vacant space beneath the Lower East Side could one day become the underground equivalent: a fanciful subterranean park known as "The Lowline."

"This is an absolutely ambitious project, and I think that's exactly why it needs to happen," said Dan Barasch, co-founder of the Lowline.

On Thursday, city officials gave it a green light, giving the architects who dreamed up the idea eight years ago a shot at making it a reality.

"When you think about other ways in which New Yorkers have been creative to use old industrial spaces and turn them into interesting, funky, innovative amenities for neighborhoods and for tourists, this is, in my view, the next iteration of that," said Deputy Mayor Alicia Glen.

The Lowline Lab has been open in an Essex Street building since October, showing how sunlight could filter into an underground space to grow plants, fruits and vegetables.

"We've, I think, really proven the scientific model here, which is really a microcosm of what we'll build in the future. So we're confident that the technology does work," Barasch said.

The space in the subway station was once a terminal for trolleys that crossed over the Williamsburg Bridge. Measuring about an acre, it has been unused since 1948.

Several hurdles must be cleared before it's reborn as a below-ground park. For the project to move forward, the Lowline, over the next year, has to raise $10 million in funds, hold five to 10 public design meetings and also submit its design proposals to the city.

The subway station space is alongside the J, M and Z subway lines. At the Delancey/Essex station, riders were intrigued and bemused by the Lowline concept.

"Sounds kind of cool. Sounds like an experiement for like a space station or something," said one rider.

"It would be nice, but yeah, that's tricky," said another.

"It's ridiculous," said a third.

Officials insist the plan can get off the ground underground.

"Like most things in New York, there will be some skeptics. And then when it comes to fruition, everybody will go, 'That's the greatest thing that ever happened, and we should do that again,'" Glen said.