The Los Angeles Metro Rail is an urban rail transit system serving Los Angeles County, California, United States. It consists of seven lines, including five light rail lines (the A, C, E, K, L lines) and two rapid transit (known locally as a subway) lines (the B and D lines) serving 99 stations. It connects with the Metro Busway bus rapid transit system (the G and J lines), the Metrolink commuter rail system, and several Amtrak lines. Metro Rail is owned and operated by the Los Angeles County Metropolitan Transportation Authority (Metro) and started service in 1990. It has been extended significantly since that time and several further extensions are either in the works or being considered. In , the system had a ridership of , or about per weekday as of . Los Angeles had two previous rail transit systems, the Pacific Electric Red Car and Los Angeles Railway Yellow Car lines, which operated between the late 19th century and the 1960s. The Metro Rail system uses many of their former rights-of-way, and thus can be considered their indirect successor. Current system Lines In Los Angeles Metro terminology, common with most other metro systems, a line is a named service, defined by a route and set of stations served by trains on that route. (The word does not refer to a physical rail corridor, as it does in New York City Subway nomenclature.) Metro also uses the same line letter naming system for its Metro Busway services (which are bus rapid transit routes operating in transitways). Seven Metro Rail lines operate in Los Angeles County: The B and D lines follow a fully underground route, and the C Line follows a fully grade separated route. The A, E, K and L Line routes run in a mix of environments, including at-grade in an exclusive corridor, street running, elevated, and underground. The two subway lines (B and D) share tracks between and , while two of the light rail lines (A and E) share tracks between and . Future system expansions are expected to use more shared light-rail tracks. Stations The large majority of light rail stations are either at ground level or elevated, with some trenched or fully underground. All heavy rail (i.e. rapid transit) stations are fully underground. Future light rail lines will add more underground stations to the system. Stations include at least two ticket vending machines,