The work will replace the existing two-track corridor with a new four-track alignment spanning approximately 1.6 km, tie into the current three-track system north of L’Enfant Interlocking and set the stage for the fourth track under a later procurement. 

“The project’s limits do not extend to the interlocking but will tie into the existing three‑track system,” said Maritza E. Ferreira, vice president of communications for Skanska. “The fourth track will be tied in under another package.”

Under a progressive design-build model, the Skanska–FlatironDragados JV will construct seven new rail bridges and associated pedestrian spans.  

Additional elements include installing continuous-welded rail, modern signaling and performing extensive track-bed upgrades, including resilient fastener systems to reduce vibration in adjacent parklands.

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Among its sustainability measures, the team will specify weathering steel for all structures “to meet aesthetic goals and eliminate the need for coatings,” Ferreira said. 

Stone salvaged from the existing substructure will be repurposed as cladding on new elements. Parking lots will feature pervious pavers and best management practices to limit stormwater runoff, and construction water will be treated and recycled to curb both consumption and wastewater discharge.

Skanska said it will use material staging yards and truck marshaling areas to minimize the rail corridor footprint, reduce impacts on existing traffic patterns and accommodate large-scale community events along the alignment.

Construction crews are scheduled to mobilize this month, coordinating closely with CSX Transportation, Amtrak, Virginia Railway Express, the Washington, D.C. Dept. of Transportation, National Park Service and Federal Railroad Administration to minimize disruptions to passenger and freight services.

This northern package is the first of two under the Long Bridge Project. A south package—comprising a new two‑track river crossing plus a combined bicycle‑pedestrian span—was awarded earlier in 2025 to a separate joint venture. 

The two phases will double-track capacity across the Potomac River, alleviating a critical chokepoint on the Northeast‑Southeast rail corridor.

Ferreira said substantial completion is anticipated in the fourth quarter of 2030.

*Correction: The amount of the Skanska–FlatironDragados JV is valued at $1 billion, not $658 million as originally reported.