Bay Area Rapid Transit BART Take a Look in The Tunnel San Francisco public transportation system

Bay Area Rapid Transit, is a rapid transit public transportation system serving the San Francisco Bay Area in California. Began operation: September 11, 1972
Annual ridership: 124.2 million (FY 2017)
Did you know: BART is the 10th-busiest North American rapid transit system by annual ridership (132,314,200)
Bay Area Rapid Transit (BART) (/bɑːrt/), is a rapid transit public transportation system serving the San Francisco Bay Area in California. The heavy rail elevated and subwaysystem connects San Francisco and Oaklandwith urban and suburban areas in Alameda, Contra Costa, and San Mateo counties. BART connects 48 stations along six routes on 112 miles (180 km) of rapid transit lines, including a ten-mile spur line in eastern Contra Costa County which utilizes diesel multiple-unittrains and a 3.2-mile (5.1 km) automated guideway transit line to the Oakland International Airport. With an average of 423,000 weekday passengers and 124.2 million annual passengers in fiscal year 2017,[1] BART is the fifth-busiest heavy rail rapid transit system in the United States.
Bay Area Rapid Transit (BART)
A westbound BART train in West Oakland in 2018
Overview Locale San Francisco Bay Area
Counties: Alameda, Contra Costa, San Francisco, and San MateoTransit typeRapid transitNumber of lines6 lines
5 rapid transit lines
1 AGT line
Number of stations48
2 under construction
7 planned/proposedDaily ridership423,395 weekdays
188,190 Saturdays
133,482 Sundays
(FY 2017 average)[1]Annual ridership124.2 million (FY 2017)[1]Chief executiveGrace CrunicanHeadquartersKaiser Center
3-cars (AGT)Headway15–20 mins (by line); 3–8 mins (between trains at busiest stations)[citation needed]TechnicalSystem length109 mi (175 km) (rapid transit)[3]
3.2 mi (5.1 km) (AGT)[3]Track gauge5 ft 6 in (1,676 mm)[3]Minimum radius of curvature120 m (390 ft)ElectrificationThird rail, 1,000 VDC[3][4]Average speed35 mph (56 km/h)[3]Top speed80 mph (130 km/h);[3]70 mph (110 km/h)[5]during normal operationsSystem map
BART is operated by the San Francisco Bay Area Rapid Transit District, formed in 1957. The initial system opened in stages from 1972 to 1974. As of 2018, it is being expanded to San Jose with the contiguous Warm Springs and Silicon Valley BART extensions.