Slattery Skanska, in joint venture with The Lane Construction Corporation and Granite Construction Co., was awarded a $220 million design-build contract by Washington Metropolitan Area Transit Authority to construct a 3.1 mile extension of the Blue Line Metrorail from the existing Addison Road Station to Largo Town Center. The project, known as the Largo Extension, is located in Prince George's County, MD. The line expansion also provides for a new transit station, which has also been awarded to this joint venture.

The route begins approximately 1,000 feet east of the existing Addison Road Station platform with an at-grade double track alignment that requires retained cut construction. The scope of work also includes installing approximately 780 feet of new tail track, which will extend past Largo Station under Arena Drive. Most of the work on the extension involves below-grade cut-and-cover tunnels. Because work is being done in sensitive areas, environmental mitigation will be conducted in strict compliance with standards that were outlined in the clients FEIS. As the rail extension will run above ground for about 2,000 feet, erection of elevated guideways are also included in the scope of work.

There are also eight widened jet fan sections for tunnel air circulation and two crossover areas along the new line. Auxiliary equipment rooms, near the stations will be constructed as part of this contract. Integration of system elements including track, traction power, automatic train control, communications and systems into the current WMATA operating structure as well as the new stations is critical.