Comment by jim

My fear on this sort of setup is that the two lines which serve Arlington Cemetery would have too great a headway at rush hour. We're likely talking about 10 or 12 minute headways on the Blue and Silver lines (which means you'd have to divert some Orange line trains to Largo or you'll have riots on PG County Blue line platforms). That's a long and frustrating wait for someone who wants to go to (say) Farragut from King St. and has to watch several Yellow line trains go by before he sees a Blue.