The Market Street Subway is a tunnel that carries both rapid transit

Rapid transit

A rapid transit, underground, subway, elevated railway, metro or metropolitan railway system is an electric passenger railway in an urban area with a high capacity and frequency, and grade separation from other traffic. Rapid transit systems are typically located either in underground tunnels or on...

 and light rail

Light rail

Light rail or light rail transit is a form of urban rail public transportation that generally has a lower capacity and lower speed than heavy rail and metro systems, but higher capacity and higher speed than traditional street-running tram systems...

 traffic in San Francisco, California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. It runs under the length of Market Street between Embarcadero Station

Embarcadero Station

Embarcadero is a BART and Muni Metro station in the Financial District of San Francisco. The easternmost stop on the Market Street Subway, Embarcadero acts as a major hub for passenger movement throughout the San Francisco Bay Area...

 and Castro Street Station

Castro Street Station

Castro Street Station is a Muni Metro station at the intersection of Market Street, Castro Street, and 17th Street in The Castro district of San Francisco, California...

 and is used by both Muni Metro

Muni Metro

Muni Metro is a light rail system serving San Francisco, California, operated by the San Francisco Municipal Railway , a division of the San Francisco Municipal Transportation Agency...

 and BART. The upper level is used by Muni Metro lines and the lower level is used by BART lines. BART does not run through the whole subway; it turns south and runs under Mission Street

Mission Street

Mission Street is a north-south arterial thoroughfare in San Francisco, California that runs from the city's southern border to its northeast corner. The street and the Mission District through which it runs were named for the Spanish Mission Dolores, several blocks away from the modern route. Only...

 southwest of Civic Center Station

Civic Center Station (San Francisco)

Civic Center/UN Plaza Station is a Muni Metro and Bay Area Rapid Transit station near the Civic Center in downtown San Francisco, California. It is along the Market Street Subway below Market Street between Seventh Street and Eighth Street...

. The eastern end of the BART level is connected to the Transbay Tube

Transbay Tube

The Transbay Tube is the part of BART which runs under San Francisco Bay in California. The tube is 3.6 miles long; including approaches from the nearest stations , it totals 6 miles...

. On the Muni Metro level, the southwestern end of the Market Street Subway connects to the much older Twin Peaks Tunnel

Twin Peaks Tunnel

The Twin Peaks Tunnel is a long light rail transit/streetcar tunnel in San Francisco, California, United States, running under Twin Peaks. When it was opened on February 3, 1918, it was one of the longest railway tunnels in the world . It was the longest U.S...

, and the northeastern end connects to the surface along the Embarcadero. The Embarcadero portal was not originally part of the Market Street Subway and was opened in 1998. It is used by the N Judah

N Judah

The N Judah is a Muni Metro line in San Francisco, California, so called as it runs along Judah Street for much of its length, named after railroad engineer Theodore Judah. It links downtown San Francisco to the Cole Valley and Sunset neighborhoods. It is the busiest line in the Muni Metro system...

 and the T Third Street lines.

The K Ingleside

K Ingleside

The K Ingleside is a Muni Metro line in San Francisco, California, mainly serving the West Portal and Ingleside neighborhoods. It was one of San Francisco's streetcar lines in the early 20th century, and was converted to modern light rail operation with the creation of the Muni Metro system in the...

, L Taraval

L Taraval

The L Taraval is a Muni Metro line in San Francisco, California, mainly serving the Parkside District, an area which is immediately south of the Sunset District and which is regarded by some as the southern part of the Sunset District...

, M Ocean View, and T Third Street Muni Metro lines run through the entire tunnel and into the Twin Peaks Tunnel. The J Church

J Church

The J Church is a Muni Metro railway line in San Francisco, California mainly serving the Noe Valley and Balboa Park neighborhoods, connecting them to downtown. It began as one of San Francisco's streetcar lines in 1917, and was converted to modern light rail operation with the creation of the Muni...

 and N Judah

N Judah

The N Judah is a Muni Metro line in San Francisco, California, so called as it runs along Judah Street for much of its length, named after railroad engineer Theodore Judah. It links downtown San Francisco to the Cole Valley and Sunset neighborhoods. It is the busiest line in the Muni Metro system...

 lines leave the tunnel through an exit that connects to Church Street.

Stations on the Market Street Subway

There are a total of seven stations in the tunnel. Four are used by BART, five by all of the Muni Metro lines, and two by four of the Metro lines:

• Embarcadero Station
  Embarcadero Station
  Embarcadero is a BART and Muni Metro station in the Financial District of San Francisco. The easternmost stop on the Market Street Subway, Embarcadero acts as a major hub for passenger movement throughout the San Francisco Bay Area...
  
   - J, K, L, M, N, and T Muni Metro lines, BART
• Montgomery Street Station
  Montgomery Street Station
  Montgomery Street Station is a Muni Metro and Bay Area Rapid Transit station in the Financial District of San Francisco, California. It is located on the Market Street Subway beneath Market Street, between Montgomery Street and Sansome Street...
  
   - J, K, L, M, N, and T Muni Metro lines, BART
• Powell Street Station
  Powell Street Station
  Powell Street Station is a Muni Metro and Bay Area Rapid Transit station near the intersection of Market Street and Powell Street in downtown San Francisco, California. The station is located along the Market Street Subway and extends underground from Fourth Street to Fifth Street. Hallidie Plaza...
  
   - J, K, L, M, N, and T Muni Metro lines, BART
• Civic Center Station
  Civic Center Station (San Francisco)
  Civic Center/UN Plaza Station is a Muni Metro and Bay Area Rapid Transit station near the Civic Center in downtown San Francisco, California. It is along the Market Street Subway below Market Street between Seventh Street and Eighth Street...
  
   - J, K, L, M, N, and T Muni Metro lines, BART
• Van Ness Station
  Van Ness Station
  Van Ness Station is a Muni Metro station on the Market Street Subway at the intersection of Market Street and Van Ness Avenue in San Francisco, California. The station consists of a concourse mezzanine on the first floor down, and a single island platform on the second level down...
  
   - J, K, L, M, N, and T Muni Metro lines
• Church Street Station
  Church Street Station (San Francisco)
  Church Street Station is a Muni Metro station at the intersection of Market Street, Church Street and 14th Street in San Francisco, California. The J Church, which enters and exits the Market Street tunnel in a portal near the station, has an aboveground stop on Church and Market Streets...
  
   - K, L, M, and T Muni Metro lines (The J stops at the station above-ground and the N stops nearby)
• Castro Street Station
  Castro Street Station
  Castro Street Station is a Muni Metro station at the intersection of Market Street, Castro Street, and 17th Street in The Castro district of San Francisco, California...
  
  - K, L, M, and T Muni Metro lines