Metro Train LinesThe Green Line goes east from near LAX connecting with the Blue Line in central LA and continuing east to Norwalk. (There's a shuttle bus from LAX to the Green Line station.)
The Blue Line runs from Long Beach to Downtown LA where it meets the Red Line.
The Red Line runs from Union Station west through downtown and up through Hollywood to North Hollywood. This is the only line that's predominantly underground, so it's the fastest line. It's also the most useful for visitors, since it stops near many popular tourist attractions including Universal Studios Hollywood, Hollywood & Highland and Olvera Street.
The Purple Line Parallels the Red Line from Union Station to Wilshire and Vermont and then diverts to travel two more stops west down Wilshire. This route is intended to eventually travel along Wilshire to the beach.
The Expo Line Runs from the 7th Street Metro Station downtown, where it connects with the Red, Blue and Purple lines, west through Exposition Park (home of the Natural History Museum, California Science Center and more) and USC to Culver City.
The Gold Line runs from Union Station northeast to Pasadena.
The Metro Orange Line (through the San Fernando Valley) and Wilshire Rapid Express (downtown to Santa Monica Pier) are express buses that operate on proposed future train routes. They show up as thinner orange and purple lines on Metro train maps.
Additional Metro buses extend routes from Metro stations to areas not reached by the trains. Other local transit systems also have buses that serve Metro stations.