Maryland Makes Headway on $5.6B Purple Line Project
Improving Mobility and Connectivity: Design-Build Team Celebrates Progress on Purple Line Construction in Maryland
Motorists who travel through the congestion-choked suburbs of Washington, D.C., have long needed a faster, more reliable east-west transit option. To improve mobility and connectivity inside the Capital Beltway, a consortium of public and private entities is building the Purple Line, a light-rail system that will link Montgomery and Prince George’s counties.
The new 16.2-mile transit line features 21 stations that link major economic and job centers in the cities of Bethesda, Silver Spring, Takoma-Langley Park, College Park and New Carrollton. It will provide direct connections between three lines on the existing Washington Metropolitan Area Transit Authority (WMATA) Metrorail system, all three Maryland Area Regional Commuter (MARC) commuter rail lines, Amtrak’s Northeast Corridor line, and local transit options.
Additionally, the construction package includes the completion of two important trails in the area – the Capital Crescent Trail between Bethesda and Silver Spring and the Green Trail along Wayne Avenue to Sligo Creek – as well as a new bike path through the University of Maryland campus.
Under construction since August 2017, this $5.6 billion megaproject is the largest public-private partnership (P3) transit development in North America today. It is owned by the Maryland Department of Transportation Maryland Transit Administration (MDOT MTA), which engaged Purple Line Transit Partners (PLTP) as a private-sector partner to design, build, operate and maintain the light-rail system. The 36-year performance-based agreement includes a six-year design and construction period followed by a 30-year operations and maintenance period.
The Purple Line is expected to enter full service in mid-2023, though portions of the project may turn operational as early as 2022. Daily ridership is anticipated to exceed 74,000 by 2040, removing approximately 17,000 cars from congested roadways each day.
Light-Rail Alignment and Vehicle Design
The project alignment will be largely at grade with one short tunnel section in the Long Branch community of Silver Spring, three elevated sections and several bridge structures. Although the Purple Line will connect to Metrorail and MARC lines, it will remain physically and operationally separate. Besides the 21 transit stations (16 at-grade stations, three elevated stations and two below-grade stations), the PLTC team is tasked with building two rail car storage and maintenance facilities.
Initially, the Purple Line will operate with 26 articulated light-rail vehicles (LRVs), each one costing approximately $7 million to build. The electric-powered trains are engineered to run quietly thanks to features such as special wheel profiles, noise-dampening wheel skirts and other noise-reducing measures. They also have an ADA-compliant design scheme, including low floors allowing passengers to board without climbing steps, and onboard storage for bicycles.
Currently, the rolling stock is being built in CAF USA’s plant in Elmira, New York. Final assembly is scheduled to take place at Glenridge Yard in Prince George’s County. Once in service, the 140-foot-long LRVs – each with a total capacity of around 430 passengers – will run every 7 1/2 minutes during peak periods and every 10 to 12 minutes in off-peak hours, depending on the time of day.
An Experienced Design-Build Team
The Purple Line is being constructed under a $2 billion design-build contract held by Purple Line Transit Constructors (PLTC), a joint venture comprising Fluor, The Lane Construction Corporation and Traylor Bros., Inc. Each firm possesses extensive experience in design-build project delivery, an approach proven effective in expediting large, complex projects worldwide.
The PLTC group is utilizing the local knowledge, experience and execution capabilities of lead design firm Atkins and dedicated design subconsultant Mott MacDonald. Other key project team members include construction subcontractors M.C. Dean, Inc. and Hensel Phelps, as well as light-rail vehicle supplier CAF USA and rolling stock adviser SNC-Lavalin (formerly known as Interfleet Technology).
Safety is a top priority for the entire team of design and construction experts. “Our number one goal is to provide a quality project while building in a safe environment,” says Carla Julian, Senior Manager of Public Affairs and Community Outreach for PLTC. “We put all of our employees through major safety training. Each employee has the right to stop work if something seems unsafe.” A dedicated safety team has also been assembled to help safeguard and protect construction personnel and the public.
Keeping the public apprised of construction activities is another strategy that bolsters safety (and helps with project buy-in). In the last two years alone, the PLTC team has hosted more than 400 community meetings. Purple Line information is also communicated via social media, website updates, email and text notifications, and in person.
Collaboration and Coordination are Key
Most of the alignment for the Purple Line is currently under construction, an effort complicated by utility relocations involving 15 different service providers. Julian emphasizes that having the appropriate personnel in the field has been critical to moving construction forward in the best possible way.
According to project officials, the Purple Line’s biggest construction hurdles include working within heavily populated, urban areas and coordinating with third parties such as homeowners, businesses, municipalities, and other transit operators.
In addition to keeping the project moving forward within budget and on schedule, the project team must focus on maintaining access for community members mitigating negative impacts. These efforts require major resources and layers of communication and outreach, notes Julian.
To illustrate her point, Julian points to work being performed around CSX freight rail tracks. Oftentimes, PLTC has had to rework or reshuffle the construction schedule to accommodate the other transit operator’s numerous requirements.
She adds, “And then with WMATA, we have the Bethesda station where we’re building our shaft.” The 160-foot shaft will eventually tie into the Metrorail Red Line. “There’s immense coordination going on with WMATA for the shaft, as well as at the Silver Spring Transit Center, where there are mega buses going in and out of there.”
Each week, a two-hour technical coordination meeting is held with “the right people” to plan for major road closures and other construction activities that might impact the urban transit center, Julian says. These key decision-makers include representatives from PLTC, WMATA, the county and bus operations.
Construction Milestones and Unique Solutions
The project reached three important milestones this year. The first occurred in late February, when crews broke through the western portal of the 1,020-foot Plymouth Tunnel after eight months of excavation, completing this phase of work ahead of schedule. In July, the project team hosted a topping-out ceremony to celebrate the completion of framework for the Operations and Maintenance Facility, which will house the future Purple Line Operations Control Center. This 170,000-square-foot complex, located off Veterans Highway in the Glenridge community, will also support rail car maintenance and the re-fabrication of running gear and train control systems. Then, in September, the first section of track was successfully installed near Ellen Road and Hanson Oaks Drive – a sign to many community members that the long-awaited transit line is making significant progress.
A variety of innovative construction solutions are being used to enhance efficiency, productivity, accuracy and safety. For instance, workers performing stakeless grading activities have incorporated the Amberg surveying system to scan conditions and confirm vertical and horizontal alignment. Other examples of cutting-edge technologies include machine control systems and geotechnical instrumentation to provide real-time monitoring of noise, vibration and movement.
Tunneling crews have utilized the sequential excavation method, a modern technique commonly used to save time and money when drilling and blasting shallow, mixed-face tunnels. For deep shaft and open-cut tunnel locations, the team is using a heavy-duty hydraulic strut and waler excavation support system provided by United Rentals.
“Excavations in soil (specifically deep excavations like the kinds required in the Bethesda Station south entrance and the Plymouth Tunnel) require an engineered support system to maintain a safe opening in the excavated ground,” explains PLTC Project Engineer Jeff Hammer. The Mega Brace system custom-built for Purple Line construction consists of wood beams to retain the soil, vertical steel beams to retain the wood beams and larger steel beams to transfer between all the vertical steel beams. In addition to addressing the pressure transfer between vertical beams, this product’s hydraulic elements are quickly installable and reusable. The ease of use, Hammer adds, mitigates many issues often encountered with the large, steel beam systems traditionally used in such situations.
Another helpful tool is an independent IBSS (Internet Base Station Service) network, which enables crews to have GPS coverage along the entire project length without any repeaters or additional equipment. Also, the design-build group is using OpenRoads, an advanced 3-D modeling program offered by software developer Bentley Systems.
A Corridor of Opportunity
The Purple Line also aims to support community revitalization and transit-oriented development in the region. According to a recent joint study by the American Public Transportation Association (APTA) and the National Association of Realtors, public transportation plays a critical role in boosting commercial and residential real estate market sales. The data also shows that residents of transit-oriented areas experience lower transportation costs, have higher access to jobs and are less likely to own cars.
APTA further stipulates that every $1 billion invested in public transportation supports more than 50,000 jobs and every $10 million in capital investment in this sector increases business sales by $30 million.
“Public transit’s benefits go beyond moving people from point A to point B,” affirms APTA President and CEO Paul Skoutelas. “Public transportation is a valuable investment in our communities, our businesses and our country.”
Back in 2017, a community agreement was launched to create pathways to opportunity for all who live, work and invest along the Purple Line corridor. Developed and led by the Purple Line Corridor Coalition (PLCC), the plan seeks to support and grow local businesses, build a thriving labor market, ensure housing choices and support vibrant, sustainable communities.
This progressive initiative is the result of a four-year process spearheaded by the University of Maryland’s National Center for Smart Growth (NCSG) and several community stakeholders, who together, form PLCC. “We are at the cusp of an unprecedented opportunity for economic growth and expansion – not just along this corridor, but for the entire metropolitan region,” says Gerrit Knaap, Director of the NCSG and Architect of the PLCC. “We have a shot to shape that growth sustainably, equitably and in ways that create new pathways to opportunity, particularly for the culturally rich but economically fragile communities that dot the corridor.”
As the bi-county Purple Line project moves forward, it will be interesting to see how regional leaders and community stakeholders decide to leverage this once-in-a-generation transit development.