Complex sentence: The project will connect the Metro Expo Line (which already connects venues in Santa Monica to venues at Exposition Park and in Downtown Los Angeles) to the Metro Gold Line, which will then allow for direct rail service between Santa Monica and East Los Angeles.
Split into simpler sentences: The project will connect the Metro Expo Line, which already connects venues in Santa Monica to venues at Exposition Park and in Downtown Los Angeles, to the Metro Gold Line. This will allow for direct rail service between Santa Monica and East Los Angeles.