I think they do it in Germany and France already. If memory serves the German ICE (Inter City Express) does 300kph on the same lines as their freight. The Germans use the cement rail road ties for 90% plus of their rails. I know they are starting to use them in the U.S. but that might be a good start for the high speed rail here.I'm thinking more freight - I know it moves a lot by rail already - but you still see thousands of trucks criss-crossing the country hauling freight. Long distance high speed A to B rail would be interesting, but almost would require their own dedicated lines as well - you can't have a 200mph train on the same tracks as a 55 or 60mph mile long freight hauler.