Daily Kos: Open Thread - the candidates as trains
http://www.dailykos.com/storyonly/2008/10/5/8551/84342/775/620614
Damn Interesting - The Gravity Express
http://www.damninteresting.com/?p=696
"One interesting property of the Gravity Express is that its transit time would always be very, very close to forty-two minutes regardless of the distance travelled."