Manhattan is home to New York City’s highest concentration of subway lines, with over 20 lines running every day compared to 18 in Brooklyn, 12 in Queens, and 7 lines in the Bronx. Despite Manhattan’s higher population density, population growth percentages in Brooklyn, Queens, and the Bronx have all outpaced Manhattan in the last decade. Outer borough populations are largely underserved by the Metropolitan Transportation Authority (MTA), as there are no trains that connect Brooklyn, Queens, and the Bronx to each other. This often requires commuters to travel through Manhattan, causing average commute times to reach over an hour. For example, to travel from Brooklyn to its neighboring borough, Queens, it takes an average of 63 minutes one-way.
The Interborough Express (IBX) MTA project formally proposed by Governor Hochul in 2022, sought to address this commuting gap (Fig. 1). The IBX is a transit project that intends to connect Brooklyn and Queens through a 14-mile track constructed around an existing freight line. The project will connect to 17 different subway lines in addition to the Long Island Rail Road (LIRR) to streamline travel for residents in these boroughs. The estimated end-to-end travel times are targeted to be less than 40 minutes which would be a significant reduction for residents.
Timeline: The Triboro to the IBX
1996: The Regional Plan Association (RPA) first introduced the concepts for outer borough connections in their third regional plan. The not-for-profit regional planning organization proposed a project called the Triboro as a part of their mobility campaign in 1996. The Triboro plan sought to expand the existing rail network to connect Brooklyn, Queens, and the Bronx (Fig. 2). Intersecting various existing subway lines, the Triboro idea was a 24-mile line from the northeast area of the Bronx to south Brooklyn. RPA. planners felt the line would open up travel between the north-south NYC corridor for underserved transit boroughs. To reduce project costs and time, the new line would build upon existing rail right-of-way, an area of land that is designated for railway transportation, already established by freight lines. This plan laid the groundwork for what would soon become the IBX
2020: The MTA signed a $1.3 million contract with an infrastructure firm to conduct a feasibility study on an abridged version of the Triboro in January of 2020. The Bronx line was cut when the study revealed the Triboro’s proposed line between Queens and the Bronx was already occupied by Amtrak. Deciding to reroute the Bronx line to Manhattan and Westchester in an additional project, the Triboro plan became a 14-mile project from Jackson Heights, Queens, to Bay Ridge, Brooklyn, as depicted in Fig. 1. The study also explored three types of rails: conventional rail, light rail, and bus rapid transit. Though each rail alternative had merits, the light rail offered the highest potential weekday ridership of 87,800 riders and the lowest average runtime of 39 minutes, even though it was also the most expensive proposal.
2022-2023: Two years after the feasibility study, Governor Hochul officially announced plans to move forward the IBX plan at her 2022 State of the State address, prompting the MTA to begin their environmental review process. Between May 19, 2022, and August 16, 2023, the MTA held three town hall meetings to guide the project and promote public engagement. In January 2023, the MTA selected the light rail mode for the IBX in their Planning & Environmental Linkages Study.
2024: The 2025 state budget highlights included $45 million for engineering on the IBX, signifying a key step forward for the construction and formal review of the project. The MTA also put out a project request for IBX design and formal environmental review. This review and design process was estimated to take about two years.
2025-2029: The MTA released its 2025-2029 IBX funding plan, requesting $2.75 billion for environmental review, design, and construction. However, the plan has yet to receive state legislative approval. With an MTA funding deficit of $33.4 billion, many public transit projects like IBX have been left without a formal timeline. Hopes for project completion by 2027 have dwindled as IBX’s 2025-2029 budget has yet to be approved.
Project Goals and Benefits
The main goal of the project is to improve commuter experience, reduce travel time, and open a key transportation corridor for residents of Brooklyn and Queens. There are nearly 1 billion residents located along the line, about 70% are minority communities, and ⅓ of the community members are 1.5 times below the poverty line. In addition to opening up and streamlining transportation for NYC residents at large, the IBX is understood as an equity-building project. Since it serves many low-income and minority communities, proponents of the project see it as a great amenity for historically underserved populations.
To highlight the proposed efficiency gain from the IBX, the MTA used a hypothetical scenario of a resident living in East Bushwick, Brooklyn, attempting to travel to her office in Midwood, Brooklyn. With the current railway system, she would have to ride into Manhattan for a Midwood transfer (Fig. 3). However, with the IBX, she could ride one train from Bushwick to Midwood without a Manhattan transfer, cutting her commute by 30 minutes per trip, 60 minutes per day, and 261 hours per year. Earning this time back, she can now use it on household responsibilities, education, or paid work.
Figure 3 (Google Maps)
Beyond efficiency, the IBX would cut passenger vehicle use and greenhouse gas emissions (GHGs). With the projected increase in ridership, Johns Hopkins and New York University researchers estimate that more than 16,000 riders would be compelled to switch from private vehicles to public transit, resulting in potential GHG emissions reductions of 29.28 metric tons per day. By providing an alternative transportation network, the IBX could also reduce congestion for both passenger vehicles and public transportation users, boosting the efficiency of transportation mechanisms across the city.
Proponents also point to economic development as a byproduct of the IBX, as it would connect residents to previously inaccessible areas. With more connection to job hubs and other boroughs, researchers expect that residents will have more access to economic opportunities. The RPA also finds that with more reliable transportation routes, the workforce will be more stable, contributing to a stronger economy. The MTA also notes that increased access to housing, jobs, education, and recreation will increase community development.
Challenges and Criticism
Logistical questions and funding gaps are the most pressing challenges to the IBX. In a committee report addressed to Governor Hochul, the NYC Bar examined various cost, organizational, and operational challenges that the IBX faces based on 2023 reports the MTA put out. The MTA estimated a construction cost of $5.5 billion, but the NYC Bar believes that figure underestimates and under-includes potential costs to upgrade freight capacity, manage structural conflicts with connecting elevated subway stations, and build the light rail along existing rail for freight trains. Without much consideration in the MTA’s report regarding the future of rail freight service, the NYC Bar is apprehensive about the project’s logistical feasibility.
The report also outlines concerns about the capacity for the MTA to deliver this project alongside a host of other projects and funding gaps, specifically its inability to receive state approval for the 2025-2029 capital budget. Much of this uncertainty comes from the delayed implementation of congestion pricing in 2024, a program that would charge cars a fee for entering lower Manhattan and raise an estimated $15 billion in bonds for the MTA. This funding boost was expected to cover a significant portion of MTA’s capital funding gap and kick-start other projects. However, backlash from the federal government under President Donald Trump’s administration has stoked concerns and uncertainty, putting the IBX project in a precarious financial position.
Another key point of tension is the proposed construction of rail through All Faiths Cemetery in Queens. The railway tunnel in All Faiths Cemetery in Queens is feared to be too narrow to accommodate a light rail in addition to existing freight rail service. While planners proposed diverting the light rail onto a Queens street to avoid the cemetery, the street-running rail presented numerous concerns including Queens traffic delays and the need for tunneling construction that would drive the cost above $5.5 billion. Given that funding the project was already a concern for the MTA, this additional hurdle presents a legitimate implementation challenge.
Conclusion
With 14 miles, 17 subway stations, and countless neighborhoods planned, the IBX opens a critical corridor for Brooklyn and Queens for social, economic, and environmental benefits. However, many stakeholders and project implementers are uncertain about the ability to deliver this project with dwindling financial resources and uncertain construction logistics. Introduced now over three decades ago, the IBX is a long-anticipated transportation system expansion. If costs, logistics, and other concerns can be resolved, it is poised to be a valuable addition to NYC’s transit infrastructure.
On October 15, 2025, the Metropolitan Transportation Authority commenced the IBX’s formal environmental review process under the State Environmental Quality Review Act (SEQRA). The beginning stages of this process involved three public meetings on October 29, November 6 and November 12 to explain the project and process.