BQX somehow became shorter and more expensive

From Crains:

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 from roughly $156 million to $248 million.

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.