It seemed like a watershed moment in February when Mayor Zohran Mamdani and President Donald Trump locked hands and eyes in the White House and posed with a mock Daily News front page with the headline “Trump to City: Let’s Build.”

A Mamdani aide said at the time that Queens-born Trump was particularly interested in one project: the long-stalled Sunnyside Yard development, a $21 billion plan to build a massive platform over a railyard – largely owned by Amtrak – and 12,000 housing units. “The president was very enthusiastic about this idea,” Mamdani spokesperson Joe Calvello said.

But what’s followed in the months since has not inspired confidence, Queens leaders said. The mayor’s office has reported scant progress, and the White House has said little publicly to match City Hall’s assessment that the president was interested in the idea. City Councilmember Julie Won, who represents the area, said in a statement that she is no longer taking the project seriously, as she hasn’t gotten a single update in months.

“The project is not shovel ready, no major stakeholders have been engaged, and absolutely no one has identified the $21 billion needed just to build the platform over the tracks,” Won said.

The project, which became the talk of Queens after the political opposites, Mamdani and Trump, clasped hands in the White House, re-emerged recently when Mamdani was asked about Sunnyside Yard during a tour in the Bronx about affordable housing initiatives in that borough.

The mayor replied that the Sunnyside Yard project “continues to be the subject of conversations.”

“The opportunity to turn land, which is currently a railyard, into somewhere that housing could be built, is one that we’re always going to be interested in talking about,” he said.

But his office has declined to comment further.

Here’s what else to know about the Sunnyside Yard initiative.

What’s Sunnyside Yard?

Queens’ Sunnyside neighborhood is home to 140 acres of trainyard, where Amtrak, Long Island Rail Road and New Jersey Transit trains come and go. Mamdani wants to build a deck over the yard, which is right next to North America’s busiest railroad interchange, creating a whole new landscape for development.

Some 12,000 affordable housing units have been proposed. Half would be Mitchell-Lama-style, sprawled among several high-rises and other structures. The project would bring an estimated 7,000 permanent new jobs, 60 acres of new public open space, schools, libraries and a regional rail hub to Sunnyside.

Who started this talk anyway?

Mamdani isn’t the first to be interested in such an undertaking. Amtrak, the primary owner of the land, approached the city about a potential development in 2014, and in 2020, the New York City Economic Development Council published a master plan for the project. Even still, Mamdani said the concept dates back even further.

“This idea has been an idea for frankly close to a century, and now we’re doing the work to try and make it into a reality,” the mayor said during the Bronx tour.

The master plan calls the development a “generational opportunity.”

What does Trump have to do with it?

When Mamdani visited the White House in February, he pitched the development to the president, asking for $21 billion in federal grants, the estimated price tag of building the deck atop the yard. That price tag doesn’t include the construction of housing and other buildings.

The conversation was in response to Trump’s request for the mayor to approach him with ”big ideas,” Gothamist reported earlier. On social media, Mamdani called the meeting with the president “productive” and said he looks “forward to building more housing in New York City.”

The White House, however, had little to say publicly – then or now. The White House did not respond to requests for comment.

What else are local leaders saying?

Jenny Dubnau, the board co-chair of the Western Queens Community Land Trust, a leading nonprofit active in land-use issues, said the project would be “ a huge misallocation of funds,” and expressed skepticism that the proposed housing units will actually be affordable.

The larger worry, she said, is “what kind of housing will be built there and who will it be affordable to.”

Won said she was surprised when word of Trump’s potential backing emerged. But now she is ready to change course.

“Our neighbors need affordable housing, and I welcome every real opportunity to build it,” Won said in a statement. “This is not a real opportunity.”

Queens Borough President Donovan Richards Jr. also has not received any formal update from the city, according to his spokesperson, Chris Barca.

The office reiterated the stance Richards took in February: “Sunnyside Yard’s untapped potential as New York City’s next great community is even more immense now than it was a decade ago.”

He encouraged a “comprehensive, community-centered planning process” in the event that a significant federal investment is secured.

What’s next?

No quick resolution is in the offing for an undertaking that requires approvals from multiple layers of government – even if each one of them were in agreement. For project proponents there may be a glimmer of hope: Mamdani recently announced that Anthony Shorris, first deputy under former Mayor Bill de Blasio, was recently named president and CEO of the New York City Economic Development Corporation.

The Sunnyside Yard proposal first emerged under the de Blasio administration.

The development office declined to comment.

Elizabeth Kim contributed reporting.