The alignment connects the cities of Bethesda, Silver Spring, College Park and New Carrollton and links them to Maryland branches of the Washington Metro Red, Green, Yellow, Silver and Orange subway lines; to three lines of Maryland’s MARC commuter rail system; and to Amtrak interstate rail service, without a trek to downtown D.C. first. The concessionaire, Purple Line Transit Partners, led by Meridiam and Star America, will operate and maintain the line for 30 years after service begins, estimated in late 2027.

Designed to connect major activity centers in Montgomery and Prince George’s counties without requiring travel through downtown Washington, D.C., the line extends  from Bethesda to New Carrollton.
Map courtesy Maryland Dept. of Transportation

Tough Times

The vision for the system took at least that long to take shape, with planning and studies dating to the late 1980s. A Fluor Corp.-led team won a $3-billion contract in 2016 for the then-estimated $5.6-billion project that would open in 2022. But it opted out in 2020, citing disputes with state transportation agencies over delays and cost overruns, fueled in part by stakeholder lawsuits and the pandemic—receiving a $250-million settlement. The current project cost now is estimated to be more than $9 billion.

“Looking back to 2020, the line was 30-40% built and we had no contractor. That was unprecedented in U.S. history,” said James Mitchell, a Purple Line project director at AECOM, which is program manager for the Maryland Transit Administration, in a post on the company website. “When the contractor downed tools, the [agency] took over day-to-day management of the project and had suddenly picked up around 150 subcontracts,” he noted. “As program managers on the project, we stepped in to pick up the pieces and take on all the subcontracts on their behalf. Our project team went from 50 full-time staff to about 130 overnight.”

The agency and Meridiam built on lessons learned. The new design-build contract included “a revised dispute process with faster timelines and a third-party dispute resolution board as a mandatory step in the process,” Jane Garvey, chair of Meridiam’s supervisory board, told ENR in 2022, adding that the management approach will also focus on improving skills such as coordination and communication.

The new financing package increased the original $2-billion total construction cost by 75% and included a $1.76-billion Transportation Infrastructure Finance and Innovation Act (TIFIA) loan to replace the original $875-million loan to finance up to 33% of $5.9 billion in eligible project costs. Other elements include $643 million in private activity bonds issued to Purple Line Transit Partners and $293 million in shareholder equity. The project reached 80% completion in three years since then, notes Ray Biggs, Maryland Transit Administration senior project director. Adds Fontirroig: “This is the most integrated P3 job I’ve ever experienced. Everyone says that on every job. Here, it’s a reality.”

Testing of the light rail line was underway well before the last rail track was installed May 8 at the future 16th Street-Woodside station in Silver Spring.
Photos courtesy MDOT/MTA Purple Line Project

Hodgepodge of Challenges

Snaking through busy streets and the large University of Maryland main campus in College Park, turning sharp corners and abutting driveways and a golf course, the project was so complex and varied that the team has nine project managers, says Julio Velez, Maryland Transit Solutions construction manager.

The alignment varies from at-grade to elevated to a 1,000-ft-long tunnel; mixed traffic to dedicated track; and greenfield, brownfield, residential and business zones. Three types of rail track are used, depending on the area, he says. Embedded track within concrete slabs or public streets is used in urban areas and through the campus. Gravel-ballasted track is used for ground-level dedicated rights-of-way. Direct fixation track, with rail bolted directly onto concrete foundations, is used in locations that have tight spaces requiring greater structural durability, such as in elevated locations and on bridges.

Considering the slew of stakeholders—including those whose properties were impacted by construction—the team did additional work such as widening roads and sidewalks, improving drainage and rebuilding some 4 miles of the Capital Crescent Trail, plus extending it about 1.5 miles as a concession to Montgomery County. Since the trail runs parallel to a portion of track alignment, in that area “every structure [such as a bridge] has to be built twice,” says Fontirroig.

The alignment runs in, over and under busy suburban streets and often next to residences.
Photo courtesy MDOT/MTA Purple Line Project

Other parts of the alignment run parallel to the CSX freight railroad alignment, requiring construction of a 2,000-ft-long crash wall. Proximity to a golf course and residential backyards required building eight 2-in.-thick, 500-ft-long vibration mats beneath the ballasted rail and 4 miles of noise wall.

In the University of Maryland section, which includes five stations, crews installed a parallel underground feeder system so trains can run on a single overhead catenary wire, and it was necessary to mitigate electromagnetic interference with college laboratories, says Fontirroig. “On the trains, there are strict requirements to measure how much energy is emanating and keep it to a threshold,” he adds. The team also coordinated with the school so that major construction occurred during the summer.

In Bethesda, crews built a sheltered area between two brand new buildings for a 150-ft-deep shaft to create an elevator link to a Metro subway station. A 30-ton gantry crane excavated about 12,000 cu yd of earth plus 20,000 cu yd of blast and drill material, says Velez.

At the Silver Spring Transit Center, the alignment runs on a steel girder flyover bridge over CSX and WMATA tracks. Crews installed some 200 micropiles beneath the train platform to support the mezzanine. “We had to remove the center portion of the platform, leaving the outer edge available,” says Fontirroig.

Crews also saw-cut the platform interior, excavating down to allow for minipile installation, topped by a pile cap supporting the flyover bridge. Work was done in three-hour night shifts to not disrupt revenue service. The alignment crosses 53 interchanges at grade and operates on three types of traffic management systems—preemption (less wait times for trains), priority (no stops) and regular traffic lights, notes Fontirroig.

Communications systems—a “football field” of cameras, audio and other equipment, says Velez—were prewired and lab tested, then reconnnected and retested via the central train control center in a 170,000-sq-ft LEED-certified facility in Glenridge in Prince George’s County, along with railcar maintenance activities. A second facility is in Lyttonsville near Silver Spring.

Embedded, ballasted and direct fixation tracks are all in use on the Purple Line project.
Photo courtesy MDOT/MTA Purple Line Project

To address small-business impacts from construction, the Maryland Dept. of Transportation created the Purple Line Small Business Grant Program in 2024. According to the agency website, it has awarded nearly 250 grants totaling $2.6 million to date in Montgomery and Prince George’s counties.

The team also has a dedicated business engagement team that has awarded more than $81,000 in Beyond the Rails grants to community groups such as youth centers, schools and job training programs. It has awarded at least $400 million in work to minority-owned and disadvantaged business enterprise firms.

The 142-ft-long Purple Line rail cars, which the team says are the longest of their kind in the U.S., each with capacity for 430 passengers, will run every 7.5 minutes at peak, with an end-to-end travel time of 63 minutes. A team led by Alternate Concepts Inc. and CAF USA Inc. will handle line operations and maintenance for the next three decades.