Inside DART's Expansion: Silver Line, D2 Subway, and the Next Decade

Dallas Area Rapid Transit (DART) operates the largest light-rail network by route miles in the United States. After a long stretch of consolidation, DART has re-entered an aggressive build phase anchored by two flagship projects: the Silver Line regional rail and the D2 downtown subway.

The Silver Line

The 26-mile Silver Line will connect DFW International Airport with Plano, threading through Carrollton, Addison, and Richardson. It uses largely existing freight right-of-way and is engineered for diesel multiple-unit trainsets compatible with future electrification.

D2: a second downtown alignment

D2 is a planned downtown Dallas subway designed to relieve the Bryan/Pacific surface alignment, where every DART light-rail line currently bottlenecks. By splitting traffic onto a parallel underground spine, D2 raises peak capacity across the entire system.

Cotton Belt, Red Line capacity, and beyond

• Red and Blue Line platform extensions to support three-car trains.
• Improved bus integration at Mockingbird and LBJ/Skillman stations.
• Future studies on a southern Dallas streetcar circulator.

For more on regional planning that frames these decisions, see our piece on the NCTCOG planning process and how infrastructure spending in North Texas is being prioritized.

Why it matters

Even modest network additions compound. A Silver Line transfer at CityLine/Bush, paired with D2's downtown bypass, materially shortens travel times for tens of thousands of daily riders — the kind of marginal capacity gain that defines mature transit networks.