For those who are interested, very fast rail has some extremely positive implications about what is possible to solve our environmental problems, such as global warming.
High speed rail is not particular energy efficient - around the same as an airplane, often worse. But unlike a jet liner, a train can run on electricity - something we have the potential to produce renewably
[WS:] You are making and interesting and very important point. I just have one question - are you talking about overall efficiency or efficiency at the high speed? The reason I am asking is that it definitely takes less energy for a train to attain its "cruising velocity" that do the same for a plane. The reason is simple, the plane must work against the forces of gravity to reach its cruising altitude (30 thousand feet or so), while the train does not. Therefore, if the plane were to make frequent stops as the train does (e.g. in the US Acela stops every 30-50 miles and I would imagine in Europe those distances are even shorter), it would waste considerably more energy on taking off and landing.
Another point, the French TGV is powered by electricity generated mostly by nuclear reactors. I have nothing against nuclear power plants - they are clean and efficient - but the US small-is-beautiful populists and enviro-nuts would go berserk if a plan of fast rail powered by nuclear plants were announced here.
Wojtek