Montgomery and Prince George’s Counties, MD

Purple Line Light Rail Transit Project

Client: Maryland Department of Transportation (MDOT), Maryland Transit Administration (MTA)
Our Role: Planning and Preliminary Engineering, P3 Procurement Bridging Documents, and Ongoing Design During Construction

Due to tremendous population growth in Montgomery County and Prince George’s County, the Purple Line light rail transit project will improve connections for residents in the densely populated northern Washington D.C. suburbs. The Purple Line is a 21-station, 16-mile light rail system that will connect riders to adjacent transit and commuter rail options with the Washington Metropolitan Area Transit Authority (WMATA), Maryland Area Rail Commuter (MARC), and Amtrak, as well as local bus services.

In 2016, MDOT and MTA announced the project would be a public-private partnership (P3) and, more specifically, take a design-build-finance-operate-maintain delivery method. A P3 is a collaborative arrangement between government agencies and a private entity to create projects that benefit the public sector.

The project involved multiple engineering disciplines, such as architectural, civil, geotechnical, structural, traffic, roadway, and systems engineering. GFT’s transportation planning and engineering consultants provided a comprehensive range of planning and preliminary design services, including preparing stormwater management concept plans, risk management plans, right-of-way acquisition plans, and a light rail transit fleet management plan, in addition to all other required Federal Transit Administration (FTA) readiness documents. We conducted various supporting technical studies, including preliminary hazard analyses and threat and vulnerability assessments for more than 17 major systems and facilities, including stations, bridges, tunnels, and yards. In addition, two separate light rail maintenance and storage facilities were designed to support the operational and maintenance demands. The construction phase of the project includes submittal reviews, survey plat development, off-site stormwater management design, and ongoing technical support across all facility and systems disciplines.

Assembled in Elmira, New York, the Purple Line light rail vehicles are currently the longest in the U.S. at 142 feet long. Each vehicle has a capacity for 430 passengers, with seating for 80, and can accommodate up to eight wheelchairs and eight bike racks. The electric-powered vehicles are designed to reduce noise pollution.

When complete, the Purple Line light rail system will improve access to existing transit services, address severe local traffic congestion, and improve mobility in one of Maryland’s fastest-growing regions. The project is expected to reduce travel times by 20% to 40% and eliminate about 17,000 car trips per day, potentially eliminating the need for nearly 50 million gallons of gas and associated congestion impacts over 20 years. This new line embodies the many long-term benefits that infrastructure projects can provide to support a thriving local economy and enhance connectivity across communities.

Key Features

Developed design, functionality, and accessibility features for 21 stations across 16 miles.
Created bridging documents to support P3 delivery.
Developed a safety and security process hazard analysis and mitigation strategy.
Completed the Final Environmental Impact Statement and associated technical studies.
Secured the National Environmental Policy Act record of decision through FTA.
Completed all FTA readiness documents to obtain the project’s Full Funding Grant Agreement.
Coordinated extensive community outreach with local, state, and federal agencies.

Outcomes

Less than a third as carbon intensive as travel by car.
Similar in carbon intensity to travel by MARC commuter rail and Metrorail.
Uses electric power, reducing air emissions into the immediate environment.
Minimizes the effects on land and water resources.
Federal Transit Administration, 2015, Outstanding Achievement Awards, Excellence in Environmental Document Preparation.