LOS ANGELES METRO HEAVY RAIL
Red Line and Purple Line

L.A.'s subway runs from Union Station in center city, and splits into two different routes five stations outbound, beyond downtown.  The shorter Purple Line heads only another two stops further out to Wilshire/Western.  The much longer Red Line goes generally northwest under the Hollywood Hills to end up at North Hollywood in the San Fernando Valley.  The system's total length is about fifteen miles, all within the city limits of Los Angeles.   

Of the fourteen heavy rail systems operating in the U.S.A., only the L.A. Metro has its entire route structure underground.  It's efficient, but hardly fascinating.