From Nationals Park to the Washington Convention Center to FedEx Field, Clark Construction has built some of the most prominent structures in and around the nation’s capital. One of its current projects is the Smithsonian National Museum of African American History and Culture.

And this month, the privately held Bethesda-based company won one of the biggest jobs in the firm’s history: construction of the second phase of the Silver Line rail extension that will provide a long-awaited rail link to Dulles International Airport.

The competition drew some of the biggest names in the industry, including Bechtel, the company building the first phase of the 23.1-mile rail line.

Clark will be building the rail line as part of a joint venture — Capital Rail Constructors — that includes Kiewit Infrastructure South and other partners.

In an interview, Pat Nowakowski, executive director of the Dulles rail project, praised Capital Rail Constructors as “excellent and highly qualified.”

“We’re pleased with the opportunity to work with them,” Nowakowski said.

Under the contract, Capital Rail Constructors will build 11.4 miles of track and six stations. Its contract is the largest of several that will be awarded in the second phase of the rail project, which is overseen by the Metropolitan Washington Airports Authority and expected to cost about $2.7 billion.

Clark was founded in 1906 and has 3,800 employees. In 2012, it had $4.07 billion in revenue. Public information about its operations is limited. The company declined to make any of its executives available to be interviewed for this report and only agreed to provide written answers to questions submitted to Capital Rail Constructors.

In addition to the work it has done in the D.C. region, Clark has also built convention centers in Los Angeles and Chicago and airport terminals in Baltimore and Orlando.

“They have a huge presence in the District and a track record of taking on big projects,” said D.C. City Administrator Allen Y. Lew, who has worked with Clark on several projects, including the Walter E. Washington Convention Center and Nationals Park.

Lew was struck by the company’s work on the convention center — at the time, the largest non-federal project to be built in the District. Such big projects often ended up entangled in lawsuits and claims by subcontractors, Lew said. But he recalled that Clark was able to complete the project with a minimum of fuss.

Clark’s joint venture partner, Kiewit, is an employee-owned company based in Omaha. It is one of the largest construction companies in North America.

Last month, Kiewit was part of a consortium selected by the Port Authority of New York and New Jersey to build a wider, bike-friendly, high-tech bridge to replace the current span between Staten Island and Elizabeth, N.J.

The Silver Line won’t be the first time Clark and Kiewit have built Metro stations. The companies partnered to build the $456 million Blue Line extension that added three miles and two stations to the system. The stations, Morgan Boulevard and Largo Town Center, opened in December 2004.

Mahmoud Hosseini, project director for Capital Rail Constructors, said in the written response to questions that Clark has worked on 38 projects for the Washington Metropolitan Area Transit Authority and a dozen projects for MWAA — work that means it is well acquainted with both transportation agencies.

“Our relationship with WMATA began in 1971 and with MWAA in 1993,” he added. “This experience makes CRC well positioned to deliver the Silver Line, Phase II given the team’s extensive knowledge of WMATA and MWAA.”

Construction on the second phase of the Silver Line extension is expected to start in 2014 and end in 2018.

Last year, plans for Phase 2 of the rail project were hung up by a debate over whether the contract should provide certain guarantees to workers in the form of a project labor agreement. Virginia Gov. Robert F. McDonnell (R) said he would withhold $150 million from the project if the contract included such a pact, which typically ensures certain wages and working conditions while barring strikes and providing managers with flexibility in making work assignments.

MWAA’s board voted not to require a mandatory agreement.

Tom Owens, a building and construction trades official for the AFL-CIO, said the labor federation has mixed views of Clark as an employer.

“There are times when they work well with us and other times when we scratch our heads,” he said. But Owens said he is hopeful that the Dulles project provides an opportunity for both interests to come together.