The tunnel alternative for Tysons was proposed for a 3.38-mile segment of the Dulles Rail project along Route 123 and Route 7 through Tysons Corner. This approach replaces an elevated Metrorail alignment while maintaining the same corridor and four station locations, all positioned underground. The strategy supports mobility and access while preserving the ground plane for future planning and redevelopment aligned with the area’s long-term vision. This project received the AIA Washington DC Chapter Unbuilt Design Merit Award (2009), recognizing its approach to integrating transit infrastructure with urban development potential.
Station entrances are expressed at the surface through steel and glass canopies over escalators and stairs, allowing daylight to penetrate into below-grade spaces. Each station includes two access points—one on either side of the street—connected underground by pedestrian walkways, providing weather-protected circulation from entry to platform. Entrances and mezzanines are constructed outside the tunnel envelope, similar to building basements, enabling future integration with air-rights development above. This approach supports the formation of a walkable urban fabric. The glass canopy system allows daylight to reach the platform level, reinforcing orientation and wayfinding, while the vaulted entry spaces use indirect lighting to highlight the structural ribs supporting the enclosure.