Nearly two and a half decades after the Regional Plan Association first proposed a circumferential subway route, the Triboro RX moved one small step closer to reality this week as the MTA announced the start of a feasibility study for part of the proposed line. The $1.3 million study will be run by AECOM and WSP and will examine passenger service on the Bay Ridge Branch, which currently serves as a freight corridor through Brooklyn and Queens.

“This project is hugely exciting,” MTA Chief Development Officer Janno Lieber said in a statement on Wednesday, “partly because it is based on the concept of squeezing more out of our already existing infrastructure so we don’t always have to build new subway lines from scratch. Putting mass transit on the Bay Ridge Branch could allow the MTA to serve more neighborhoods and provide better connections to thousands of people throughout Brooklyn and Queens – all while also creating opportunities for increasing environmentally-friendly freight rail in years to come.”

The study, which Dan Rivoli first reported on for NY1 back in October, has a broad mandate. Per the MTA’s release, it will not be limited to only a subway route but will “evaluate the potential for subway, commuter rail, light rail or bus service that would operate in conjunction with existing and planned freight rail service.” The MTA wants to develop a service that would not cost as much as, say, another phase of the Second Ave. Subway and can help connect job separates in growing neighborhoods while facilitating potential reverse commuting as well. As the MTA notes, the Bay Ridge Branch could provide passenger connections to 19 subway lines and the LIRR.

The Bay Ridge Branch is a current freight route that opened for passenger service in 1876 and last served riders in 1924. It is the Long Island Rail Road’s longest freight-only route and has been the subject of constant future plans since the RPA released its Third Regional Plan in 1996. That document [pdf] first proposed creation of a line running perpendicular to the city’s radial subway and connection to the Bronx via the “lightly-used Hell Gate Bridge.” The Triboro RX trains in that proposal would have served Yankee Stadium and could have helped modernize some of the city’s oldest elevateds around.

The current study omits the Bronx connection, reserving it for future examination and will have to account for the reality that CSX Transportation, a notoriously fickle freight operator, owns the northern half. As the MTA wants to maintain and expand freight capabilities, one potential solution could involve timesharing, and we need to look only to New Jersey Transit’s River Line for a freight/passenger time-sharing model. That, along with many other options, is bound to come up in the AECOM/WSP study.

That the MTA is conducting this study, meanwhile, is notable. The Triboro RX Line has been on the MTA’s radar at least since 2008 when then-MTA Executive Director Lee Sander talked up the circumferential line as part of the agency’s 40-year needs. I wrote up his speech and the plans in a 2008 post. During the 2013 mayoral primary, Christine Quinn wanted to implement a Triboro RX SBS route instead of rail. I wasn’t too keen on the idea then, but it too will get its fair shakedown under the current study.

Over the years, though, the RPA has persisted. Drawing parallels to the London Overground, the RPA has made The Triboro a centerpiece of its Fourth Regional Plan, complete with flashy website and reasonable price estimate. The RPA has maintained that 100,000 riders would use the route initially, and their price tag would put the line within the realm of the possible. “The major capital investments needed to build the line would include signals, new track, rail cars and stations, and possibly power substations,” the RPA has stated. “Initial estimates of costs range between $1 billion and $2 billion.”

Interestingly, this new study comes without a clear political champion, a rarity for the MTA and one that indicates a certain level of internal agency curiosity regarding this plan. The recently-released Rockaway Beach Branch Study, which I thought was designed to put the kibosh on talk of that project, had a political champion, but this one does not. Assembly rep Latrice Walker introduced a bill to mandate a study both this year and last, but that bill hasn’t passed the legislature yet. It appears that the MTA is doing this on its own, and the RPA is quite pleased.

“Regional Plan Association is thrilled that the MTA is moving forward on this study, which is the crucial first step to realize our Triboro vision,” RPA CEO Thomas Wright said. “Transit service on the Bay Ridge Line would not only provide better transit service between the outer boroughs but also cut construction and acquisition costs since the rail tracks are already there. This study will build on our initial concept, and evaluate cost, feasibility, among other issues, to help push the project forward. We are excited to keep working with the MTA and all other partners on this.”

For those of us who love to draw on subway maps with crayons, this study is a tantalizing glimpse into a potential future. Where it goes from here is anyone’s guess.