20th century In 1955, planning for Metro began with the Mass Transportation Survey, which attempted to forecast both freeway and mass transit systems sufficient to meet the needs of transportation in 1980. In 1959, the study's final report included two rapid transit lines which anticipated subways in downtown Washington. Because the plan called for extensive freeway construction within
Washington, D.C., alarmed residents lobbied for federal legislation creating a moratorium on freeway construction through July 1, 1962. The National Capital Transportation Agency's 1962
Transportation in the National Capital Region report anticipated much of the present Orange Line route in Virginia with the route following the median strip of
Interstate 66 both inside Arlington and beyond. The route continued in rapid transit plans until the formation of the
Washington Metropolitan Area Transit Authority (WMATA). With the formation of WMATA in October 1966, planning of the system shifted from federal hands to a regional body with representatives of the District, Maryland and Virginia. Congressional route approval was no longer a key consideration. Instead, routes had to serve each local suburban jurisdiction to assure that they would approve bond referendums to finance the system. Because the least expensive way to build into the suburbs was to rely upon existing railroad right-of-ways, the Orange Line took much of its present form, except that it also featured a further extension along the railroad to
Bowie, Maryland and along the Dulles Access Road to
Dulles International Airport. By 1966, WMATA and Arlington County planners had agreed "to realign the rapid transit through high-density commercial-office-apartment areas in the vicinity of
Wilson Boulevard instead of the freeway's median between the river and Glebe Road." As a result of this agreement, the Orange Line follows in Arlington the former routes of an
interurban electric trolley line, the
Fairfax line and the
North Arlington branch of the
Washington, Arlington & Falls Church Railway, that had initially spurred those areas' development. In March 1968, WMATA approved its Adopted Regional System (ARS) plan that included suburban mass transit lines that followed the median of the proposed
Interstate 66 through Virginia to Vienna and the
CSX/
Amtrak railroad right-of-way in
Prince George's County, Maryland. Service on the Orange Line began on November 20, 1978 between
National Airport and
New Carrollton, with five new stations being added to the existing network from
Stadium–Armory. When the line from
Rosslyn to
Ballston-MU was completed on December 11, 1979, Orange Line trains began following this route rather than going to the National Airport station. The line was completed on June 7, 1986, when it was extended by four stations to
Vienna in the I-66 median. On January 13, 1982, an Orange Line train
derailed as it was being backed up from an improperly closed rail switch between the
Federal Triangle and
Smithsonian stations, resulting in the deaths of three passengers. It was the first incident within the Metro system that caused a fatality,
21st century Between 2011 and 2013, service was interrupted at stations west of
Ballston–MU on designated weekends to accommodate the construction of the interconnection of the Silver Line with the existing Orange Line tracks. As a part of this project, the train yard adjacent to the West Falls Church station on the Orange Line was expanded. On June 17, 2012, select Orange Line trains were rerouted to serve
Largo Town Center under WMATA's new RushPlus+ during the weekday peak hours, alleviating crowding on the Blue and Orange Lines. These services remained in effect until July 26, 2014, when the Silver Line replaced the Orange RushPlus+. Orange Line stations between East Falls Church and Stadium-Armory began to serve Silver Line trains at the same time. From March 26, 2020 until June 28, 2020, trains were bypassing , , , , , , and stations due to the
2020 coronavirus pandemic. All stations reopened on June 28, 2020, except for East Falls Church until August 23 due to the platform reconstruction project west of Ballston-MU. From May 23 until August 15, 2020, trains terminated at Ballston–MU due to platform reconstruction at , , , and . The original plan called for trains to terminate at West Falls Church, but this was instead changed to Ballston due to effects of the ongoing COVID-19 pandemic and low ridership. Shuttle buses were provided to the closed stations. On August 16, 2020, all Orange line trains began terminating at while bypassing . East Falls Church reopened on August 23, 2020. On September 8, 2020, Vienna and Dunn Loring stations reopened. Between May 28 and September 5, 2022, all Orange Line trains were terminating at station on weekdays and Ballston–MU station on weekends due to the Platform Improvement Project which closed stations east of Stadium–Armory. Shuttle buses are provided to all closed stations. On June 3, 2023, service was suspended west of Ballston–MU for track replacement. and reopened on June 26, 2023. and reopened on July 17, 2023.
Automatic train operation on the Blue and Orange lines, which had ceased following the
2009 Red Line train collision, was allowed to resume in June 2025. The Silver line started operating within the section between Stadium-Armory and New Carrollton on June 22 2025. == Route ==