A model of the proposed Potomac Yard Metro station. From this view, you can see Station Alternative B, looking west from the Potomac River. ( City of Alexandria)

A plan to build a Metro station in Alexandria’s growing Potomac Yard community is inching along, but the estimated opening date has been pushed back to spring 2020 — more than a year out from earlier projections.

Alexandria City Manager Mark Jinks said the latest delay came when Metro determined that it would need more time than anticipated to plan and build the station.

“It’s not a setback,” Jinks said. “Clearly, we would prefer to get the station open as soon as possible. This station is in perpetuity. Therefore, whatever we build is going to have to be there looking like that for well over 100 years, and so we have to do it right.”

The $268 million station will serve Metro’s Blue and Yellow lines between the Braddock Road and Reagan National Airport stations, breaking up a 3.1-mile stretch of track that is the longest inside the Capital Beltway without a station.

“The Metro station has always been envisioned as a key transportation amenity for the entire city, but particularly for this area, which is being developed as a transit-oriented node,” said Yon Lambert, the city’s transportation director.

The area is currently served by Metroway, a dedicated bus rapid transit service that started last year and connects Crystal City, Potomac Yard and Braddock Road.

On Thursday, Metro approved an additional $5.8 million for the project’s design and engineering, bumping the cost of that portion of the project to $11 million.

The project’s costs are being fully covered by the city, which is entering a review phase for the station that will culminate in it presenting a package of preliminary design and build specifications to potential bidders, according to Alexandria’s Transportation Department spokeswoman, Kathleen Leonard. The package is slated to be completed and advertised to bidders next fall and a contract awarded by spring 2017, Lambert said.

The station is Metro’s second infill station — ones constructed between existing stops — after NoMa-Gallaudet U opened on the Red Line in 2004, and it will be built at ground level with a side-platform layout. The track location, north of Potomac Greens between the George Washington Memorial Parkway and the CSX railroad tracks, is already used by Metro, Lambert said, so construction will have to be completed alongside active tracks. The latest delay, he said, stretches the 30-month build period used for the NoMa station to 36 months.

“They learned some lessons in the NoMa-Gallaudet station project in their experience with building an infill Metro station on active tracks,” Lambert said, explaining the additional time.

Funding for the project will come from a variety of sources, including developer contributions, state grants, the local and the federal government, tax revenue, and revenue spurred by development. The city was awarded a $50 million loan from the Virginia Transportation Infrastructure Bank in January and expects to soon secure other funding deals, including nearly $70 million from the Northern Virginia Transportation Authority.

Jinks said that any loans will be repaid using tax revenue — mostly real estate taxes — generated by Potomac Yard development.

The Potomac Yard area is expected to generate about $2.4 billion in new tax revenue over the next 35 years, according to projections provided to the city. Still, the project may face additional hurdles, he said.

“This is probably one of the largest investments the city has ever undertaken,” Jinks said. “It is a complicated process and a complicated project. You’re fitting a new Metro station above and on either side of existing Metro tracks. There’s not a lot of room to work with. There are issues that are going to come up. On a project like this, you work through each one — you find alternatives, and you figure a path for it.”

The city approved a special tax district at north Potomac Yard for the station’s construction in 2010, with a slated opening in 2016. But the plan stalled after concerns were raised about the scenic easement that preserves views of the George Washington Memorial Parkway and an environmental study was conducted detailing the effect on the community and viewshed.

The Federal Transit Administration released a draft of the environmental impact statement in March, but it is not expected to be finalized until next year. The study outlines the station’s potential effect on overall development, area wetlands and views from the parkway. The study projected that daily ridership resulting from the new station could hit 11,300 trips — and lead to 5,000 fewer auto trips on area roads.

With the new station, Alexandria hopes to capi­tal­ize on the former railroad yard that now comprises a 295-acre “city within a city” and serves as a daily stopping point for thousands of residents and workers.

The area, south of National Airport and downtown Washington, is home to 3,000 residential units and 5 million square feet of office, hotel and retail space. City officials envision that a Metro station would spur more development and further establish the area as a commercial center.

Metro still hasn’t given its approval to the city’s preferred location for the station. That vote is expected to come before the end of the year, said Metro spokesman Dan Stessel.

Despite the hurdles, Lambert was enthusiastic about the project and the effect it will have on the community.

“There is a general recognition of the power of transit and how it can contribute to making this part of the city walkable and sustainable and developing in a fashion that contributes to overall benefits of all of the residents,” Lambert said. “These are things that ultimately will make the city a more desirable place to be.”