The San Francisco metro is operated by two separate companies: MUNI and BART. The two companies share four stations in the heart of San Francisco: Civic Center, Powell, Montgomery and Embarcadero. In order to switch between the two networks it is necessary to buy a ticket for each one.
While BART travels to the areas further from the city, the MUNI Metro (Municipal Transport Agency) tours the heart of the city. We can describe it as a kind of light rail link, with underground as well as above-ground stations.
The MUNI network has 6 regular lines and one special line (S) which operates during the rush hour. Although a number of lines have the same start and finish point, they all travel along different routes:
The Muni metro trains run every 7-10 minutes and, approximately and depending on the station, run between 5 a.m. and 1 a.m. Outside of these times there are night buses that travel along the L and N routes.