San Francisco International Airport station is an elevated structure about wide and long. It is located on the northwest side of the group of terminals; the west half of the station is adjacent to Garage G, while its east end connects to the north end of the International Terminal. A stub-end terminal station, the BART level has three tracks served by two island platforms. An elevated wye and crossovers to the west of the station allow trains arriving from the north or south to use any track. The south track is used for all trains departing to the north; on nights and weekends, Millbrae-bound trains use the north track. The middle track was not used in regular service until; its platform edges were blocked off. The AirTrain station, located above the west half of the BART station, has a single island platform serving the two AirTrain guideways, plus a side platform serving the inner loop. A footbridge above the AirTrain level provides access from the parking garage. BART faregates are located in the AirTrain station, and at the east end of the station where it connects to the departures level of the International Terminal.
''Wind Portal''
Wind Portal is a 2003 artwork by Sebastopol artist Ned Kahn on the surface of the cylindrical opening in the floor separating the BART station from AirTrain. Passengers transferring between the two rail services ride escalators or walk on stairs through the opening, which measures high with a radius. The artwork consists of 200,000 stainless steel disks, each in diameter and individually hung so they respond to air currents induced by train traffic. John King, urban art critic for the San Francisco Chronicle, praised it, saying it was "esmerizing... an ever-changing silver shimmer... indefinable movements reacting to distant winds as well as the whoosh of trains. The experience is hard to predict; there's a sense of anticipation."
History
A BART extension to San Francisco International Airport was first proposed in 1970 - before the initial system even opened. In 1972, a "trace" - a concrete shell with space for a station - was built into the North Terminal during its construction; it was blocked from use by later construction. Planning began in the early 1990s; after a great deal of political controversy over where the airport station would be located, construction began in 1997. The BART extension was constructed in concert with the International Terminal and the AirTrain system. The AirTrain system opened on February 24, 2003. BART service to SFIA station began on June 22, 2003. The station was initially served by the Dublin/Pleasanton line, plus a shuttle service to Caltrain connections at Millbrae station. The shuttle service was discontinued on February 9, 2004. The Pittsburg/Bay Point line began serving SFIA station, with northbound trips on the Richmond line also serving SFIA station at peak hours. Peak-hour Richmond line service began serving the station in both directions on September 13, 2004. Within the first two weeks of service to SFIA station, ridership was 50% below the projected 6,500 passenger exits per day. BART service to stations in San Mateo County is funded by SamTrans, rather than county tax revenues. As ridership stayed below expectations, SamTrans had to pay a larger-than-planned operating subsidy to BART. On September 12, 2005, in order to lower these subsidies, BART reduced service so that only the Dublin/Pleasanton line served SFIA and Millbrae stations. SamTrans and BART reached an agreement in February 2007 in which SamTrans would transfer control and financial responsibility of the SFO/Millbrae extension to BART, in return for BART receiving additional fixed funding from SamTrans and other sources. On January 1, 2008, BART increased service to the San Mateo stations. SFIA became the terminus of the Pittsburg/Bay Point line at all times, and direct service between SFIA and Millbrae was discontinued. On September 14, 2009, the line was extended to Millbrae on nights and weekends, restoring direct service at those times. During its first decade of service, ridership remained well below initial projections. Ridership has continued to increase, reaching a peak of 6,788 weekday exits in fiscal year 2016. On February 11, 2019, SFO–Millbrae line service resumed on weekdays and Sundays, with cross-platform connections to the Antioch line at SFIA station. The Antioch line continued to serve both SFIA and Millbrae on weeknights and Saturdays. On February 10, 2020, the SFO–Millbrae line began running during all BART operating hours, with the Antioch line terminating only at SFIA. In October 2019, the BART board approved development of technology for a proposed pilot program, under which BART and other public transit riders would have access to priority security screening lines at the airport.
