In case you haven't discovered it - you can click-and-drag your mouse across the lines to make sounds in addition to waiting for the lines to 'pluck' themselves
This is very cool. Here's our way of visualizing buses driving around in a novel way: <a href="http://labs.transloc.com/streetview/" rel="nofollow">http://labs.transloc.com/streetview/</a>
It's wonderful, if a little odd, to think of the NYC subway as a plucked guitar, versus the familiar steel-on-steel "ka-chunk, ka-chunk" as the trains rumble on the (unwelded) tracks.