The de Blasio administration today released plans for its Brooklyn-Queens Connector, a streetcar officials envision running along the waterfront between the two boroughs. It has been delayed by complex infrastructure challenges.

The original streetcar was expected to cost $2.5 billion and run roughly 16 miles between Astoria, Queens, and Sunset Park, Brooklyn. But the updated plan calls for a shorter route to Gowanus instead and will cost $2.7 billion. That translates to an increase in per-mile cost to roughly $248 million from $156 million.

Mayor Bill de Blasio first announced plans for the streetcar in February 2016. But as officials looked further into potential routes, they found that the rat's nest of underground infrastructure presented enormous potential for increasing costs and would need to be thoroughly studied. As Crain's reported late last year, the problem presented officials with a catch-22: By studying the infrastructure more carefully, the city insulated itself from risk in the event it had to scrap the project, but doing so caused delays and drove up costs.

The original project was supposed to be completed in 2024 and be paid for through property tax revenue as the land around the route increased in value. The updated version of the project is now expected to be operational in 2029 and would require $1 billion from the federal government, according to a report in The New York Times, which noted that the city tax revenues originally thought to be available for the BQX are being spent on other priorities, including affordable housing.

First-year ridership on the 26-stop line is expected to reach 50,000 people daily, according to the administration, and overall is expected to serve around half a million people in waterfront communities.

"The Brooklyn-Queens waterfront has experienced incredible growth. Now it's time for our transit system to catch up," de Blasio said in a statement. "The BQX is one of the biggest, most ambitious projects in a generation. It will be a challenge, but New York City is taking it on."

News of the route change was first reported by Streetsblog NYC. The city now plans to examine the environmental impact of the project and kick off the public review process in 2020. The updated plan is supported by the tram's independent booster group, Friends of the BQX.

"This commitment to moving the BQX forward is a huge win for New Yorkers who have been cut off from transit for too long—including more than 40,000 NYCHA residents along the route," the organization's executive director, Jessica Schumer, said in a statement. "With the city embroiled in a transit crisis, the BQX will serve as an innovative model for how to build new mass transit sustainably and equitably."

At a press availability Thursday, de Blasio defended the project, insisting it was a "big deal" even if it reduced commute times by as little as 10 to 15 minutes. He argued that it would become a top priority for dollars from Washington—so long as Democrats win back control of the federal government.

"We're about to have two elections, 2018 and 2020, that could entirely remake the Congress and the White House, and then we would be having a very different conversation about infrastructure," the mayor said. "In any competition for light-rail funding, this proposal would go to the front of the line instantaneously. ... Looking around the country, it would cover the most people in the smallest amount of area."

The mayor acknowledged that, after 2020, he would have just a year left in office and his successor might not pursue the BQX. But he asserted that would be on par with eliminating his signature universal pre-kindergarten program and a number of other initiatives.

He said that the city was now ready to begin conducting the environmental review necessary to gain federal grants.

But de Blasio refused to say whether he has discussed the possibility of federal funding with Senate Democratic Leader Charles Schumer, the father of the Friends of the Brooklyn-Queens Connector director quoted above.

The senator has been struggling to secure funding from the Trump administration to construct a new Amtrak tunnel under the Hudson River and to refurbish the atrophied existing conduit.