The Brooklyn–Queens Connector, abbreviated the BQX, was a proposed streetcar line in New York City. It was planned to operate on a north–south corridor along the East River between the boroughs of Queens and Brooklyn. A previous plan bearing similarities to the BQX was initially proposed in 1989 as part of a Brooklyn waterfront streetcar line connecting Red Hook with Downtown Brooklyn. A study by the city, published in 2011, found the proposal to be infeasible. A later proposal by the nonprofit Friends of the Brooklyn Queens Connector, made public in January 2016, found backing from Mayor Bill de Blasio. A director for Friends of the Brooklyn Queens Connector was appointed in May 2016, and a list of possible routings was released in November 2016.

There was criticism of the project, namely that its completion date of mid-2020s might make it obsolete; that it did not have a clear source of funding; and that it was a poor substitute for subway service. The project was abandoned after de Blasio's mayoral term ended in 2021.

Previous proposal

Since electric trolleys in Brooklyn stopped running in 1956, activists led by the Brooklyn Historic Railway Association (BHRA) had been trying to revive streetcars. In the 1990s, the BHRA received permission from New York City's government to develop a streetcar line running from Beard Street to Borough Hall. The association's president Robert Diamond collected disused PCC streetcars that had been used in Boston and Buffalo for potential use on the new line. By 1999, the group had begun laying new track for the project in Red Hook. However, in 2003, transportation officials elected to revoke Diamond's rights to the route's right-of-way. Instead, officials intended to sell the rights to the highest bidder in the event that the project ever moved forward. Diamond's efforts to secure independent funding were not successful.

In 2005, U.S. Representative Nydia Velázquez helped obtain a $300,000 federal grant for a six-month streetcar study. Although the BHRA had estimated $10–$15 million would be required to complete the project, the New York City Department of Transportation (NYCDOT) streetcar feasibility study (completed in April 2011) concluded that the line would cost $176 million in capital funding, plus an additional $6.2 to $7.2 million in annual operating funds. A significant portion of the capital cost would be required to make modifications to Red Hook's narrow streets in order to allow streetcars to make right turns. The study concluded that, due to a number of factors such as high costs, low ridership, and physical constraints like narrow streets, a streetcar line would not be an appropriate transit solution for the area. By June 2013, Diamond had partnered with John Quadrozzi of Gowanus Bay Terminal (a concrete firm), and the Gowanus Canal Community Development Corporation in an effort to revive the project, which he now envisioned running partly underground through the Cobble Hill Tunnel, a former Long Island Rail Road tunnel under Atlantic Avenue. Diamond pursued federal funding in order to pay for the project, which he estimated would cost $50 million.

Connector proposal

Initial study The current line was initially proposed by a non-profit group, Friends of the Brooklyn Queens Connector, which commissioned a study to examine the corridor along the Brooklyn and Queens waterfront. First publicly reported on in January 2016, the study proposed a route between the neighborhoods of Astoria in Queens and Sunset Park in Brooklyn, passing through several neighborhoods on the way. News media reported that the study had estimated construction costs of $1.7 billion, annual operating costs of $26 million, and 15.8 million annual riders by 2035. The proposal included a branch going through Downtown Brooklyn to the Atlantic Avenue–Barclays Center station.

The study described a routing that would begin in Queens near the New York City Housing Authority's Astoria Houses. It would run down 21st Street south to Queensboro Plaza, west onto 11th Street to Newtown Creek. The streetcar would cross Newtown Creek into Greenpoint, then pass through Williamsburg and the Brooklyn Navy Yard using one-way streets close to the waterfront. It would turn onto Park Avenue, run to Navy Street, then through Farragut Houses, Vinegar Hill, and Dumbo. The line would then run south through Red Hook, cross the Gowanus Canal, and continue south on Third Avenue to 58th Street, where it would turn west to serve the Brooklyn Army Terminal and Industry City. From there, the line would turn east, terminating at the 59th Street subway station in Sunset Park.

Schwartz's firm worked on the proposal for over a year and considered five options aside from streetcars. One other option, Select Bus Service, was estimated to cost $1 billion to implement, and was not chosen since it would not raise property values as a streetcar would. The engineers projected 52,000 to 53,000 riders per day on the streetcar, which would have required a bus every minute. Each street car would be able to carry 150 to 175 passengers. Additionally, buses would also have a harder time navigating the 12 to 15 streets along the route. The engineers' route would have its own dedicated lanes for the whole route. The study recommended that two facilities for maintenance and storage would be built at a cost of $100 million. In addition, the streetcar would need at least 140 employees to operate the streetcars and a host of other workers, including traffic enforcement agents.

Mayoral endorsement

On February 3, 2016, the office of Mayor Bill de Blasio announced that the city would begin planning work for the streetcar line, with a formal announcement by de Blasio at his State of the City speech the following day. The BQX was promised as a way to reinvent the city's transit system, along with the Citywide Ferry Service (now NYC Ferry) proposal. City officials said that several years of additional study and review would precede groundbreaking, planned for 2019, with service beginning around 2024. Since the line would be a street-level project, the streetcar would not need state approval. The city will rely on increased real estate revenues to pay for the project. Mayor de Blasio's office commissioned a study toward researching the projected effects of the streetcar.

Under the slightly revised plan released by the city, the route would travel with 30 wheelchair-accessible stops, with an increased construction cost of $2.5 billion. There would be sixty vehicles, costing $5 million total, that would travel at , and would be separated from vehicular traffic for 70% of the route. Two bridges over the Newtown Creek and the Gowanus Canal were proposed, in the case that the Pulaski Bridge over the Newtown Creek, and the Hamilton Avenue bridge over the Gowanus Canal, aren't able to accommodate the vehicles; the Newtown Creek bridge will probably be located at Vernon Boulevard, where another bridge previously existed. A trip between Dumbo and Greenpoint would take 27 minutes via the line. The fare for the route would equal the fare of the subway and the buses.

The line is planned to use multi-section vehicles to negotiate sharp curves at Lorraine Street, Cadman Plaza, 21st Street, and Astoria Boulevard. Streetcars, rather than light rail vehicles (LRVs), are proposed to be used, despite the fact that LRVs have more capacity and shorter headways; this is because streetcars were determined to operate better within mixed-use rights-of-way, as opposed to LRVs, which were determined to operate better within dedicated rights-of-way. Electrification is proposed to be from hydrogen fuel cells within the streetcars themselves, as opposed to from overhead lines or from embedded rails. Since the BQX would operate on both dedicated rights-of-way and on streets, the BQX would use both standard traffic lights and dedicated signals during operation. Annual operating costs are estimated at $26 million.

The new line would provide a new transit route for 45,000 public-housing residents. An additional motivation for the line has been the tremendous growth in Brooklyn and Queens waterfront areas since the early 2000s.

Development In May 2016, Friends of the Brooklyn Queens Connector appointed its first executive director, Ya-Ting Liu, to oversee route operations and design. Two months later, mayor De Blasio appointed Adam Giambrone, former councilor in Toronto and chair of the Toronto Transit Commission, to serve as a consultant or "streetcar czar" for the project. On November 1, 2016, the city presented a list of possible routings of the BQX through several neighborhoods. The study found that four New York City Subway stations along the BQX's route—at Jay Street–MetroTech, Borough Hall, Court Square–23rd Street, and Vernon Boulevard—had high weekday ridership, and thus, would benefit from a BQX transfer. The city, citing the successes of other American cities' streetcar systems, estimated that the project will pay for itself by increasing the property values in the neighborhoods around it in a form of transit-oriented development, similar to how the 7 Subway Extension was built. It is expected to create 86,000 jobs through 2045.

In November 2017, Friends of the Brooklyn Queens Connector revealed a mockup of a vehicle that might be used on the BQX. The $100,000 prototype, a Citadis low-floor streetcar created by Alstom, was displayed at the Brooklyn Navy Yard. However, there was insufficient funding to start construction. Internal memos from the city around this time suggested that the project was endangered due to an ongoing dispute between Mayor de Blasio and New York State Governor Andrew Cuomo, since the state government owned some of the land that the BQX was to pass through. Shortly afterward, Liu stepped down from the director's position of Friends of the Brooklyn Queens Connector, to be replaced by Deputy Director Jessica Schumer, the daughter of U.S. Senator Chuck Schumer.

By April 2018, there was still insufficient funding, and de Blasio announced that the city would ask for federal aid for the BQX, despite the city's previous assurances to completely self-fund the project. Moreover, the streetcar project was already behind schedule: major design work had been slated to start that year, but the public approvals process that preceded it had not started. Officials predicted that even if the BQX were to be fully funded, construction would not start until at least 2020. Additionally, if the BQX's construction were to proceed, the project would interfere with the renovation of the Brooklyn Heights Promenade section of the Brooklyn-Queens Expressway, which would occur during roughly the same time frame.

Truncated plans and abandonment The BQX's proposed route between Red Hook and Sunset Park was eliminated in August 2018, and a routing through Dumbo was shelved in favor of a more direct routing through Downtown Brooklyn. The route was thereby shortened from a alignment with 30 stops to an alignment with 26 stops. This was supposedly because of cost constraints, since it was projected that the stops in Sunset Park and Dumbo would not have enough ridership to justify building the streetcar there. However, the shortened route was estimated to be more expensive than the original proposed route to Sunset Park. The new route would cost $2.73 billion, versus the original proposal, which would have cost $2.5 billion. The proposed completion date for the BQX was also postponed to 2029.