Maryland Purple Line

Geotechnical Engineering for a Complex, Multi-Jurisdictional Light Rail Corridor

The Purple Line is a 16.2-mile light rail corridor connecting Bethesda, Silver Spring, Takoma/Langley Park, the University of Maryland, and New Carrollton across Montgomery and Prince George’s Counties, Maryland. ECS delivered comprehensive geotechnical engineering services, including subsurface exploration, laboratory testing, and construction-phase support, to help advance this long-anticipated regional transit project. Across the corridor, our team completed more than 1,100 soil borings and 7,000 laboratory tests to inform design and support construction.

Challenge: Subsurface exploration across a 16.2-mile corridor

ECS deployed a coordinated, multi-office team to execute a phased geotechnical program spanning seven years. At peak activity, up to six drill rigs operated concurrently along the corridor. More than 65 employees contributed over 1.4 million work hours, completing 1,100+ soil borings and 7,000+ laboratory tests, including moisture content and soil and rock analyses. ECS also provided construction-phase support, helping maintain continuity from investigation through implementation.

Solution: Scalable field operations

Over 65 ECS employees contributed more than 1,400,000 work hours across 11 offices. ECS mobilized up to six drill rigs concurrently, completing over 1,100 soil borings and more than 7,000 laboratory tests, including moisture content and soil and rock analyses across three project phases spanning seven years. Employing almost 2,000 employees, this project supported the development of a critical transit link designed to improve regional connectivity, reduce congestion, and enhance long-term infrastructure resilience across the Maryland metropolitan area.