Random trivia about transportation in US: by 2005 rail and air transport have nearly the same energy efficiency as expressed in passenger-miles per gallon of gasoline. It is due to huge progress in air travel which became 3x-4x more efficient during the past half century while rail travel essentially remained the same.
Train vs Airplane Energy Efficiency. by David S.Lawyer mailto:email@example.com More articles by David Lawyer. 2008-2010. This is a work in progress. The historical part is mostly completed. But the technical part comparing vehicle resistance is still in a state of flux.