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[quote user="schlimm"] <a href="http://cta.ornl.gov/data/tedb29/Edition29_Chapter02.pdf">http://cta.ornl.gov/data/tedb29/Edition29_Chapter02.pdf</a> I would draw your attention to Table 2.12 on energy use by modality, in BTU per passenger mile. Amtrak 2398 Auto     3437 Airline  2995 Those figures, from Oak Ridge, would appear to show a significant advantage even for inefficient Amtrak: a 30% saving over autos.  Perhaps these numbers don't meet your engineering sniff test either? Your comparison of a Chevy Volt (or any car) to a train seems a bit strained.  Most cars are traveling with less than four occupants, often one and the average for these studies is two.  On the other hand, if you were to ride an HSR-type train in France or Germany, you would typically find it quite full. [/quote] These words appear in a banner at the top of five of the pages of the referenced document: Great care should be taken when comparing modal energy intensity data among modes. Because of the inherent differences between the transportation modes in the nature of services, routes available, and many additional factors, it is not possible to obtain truly comparable national energy intensities among modes. Several years ago the owners of the Trinity Railway Express (TRE), which is a commuter rail operation between Dallas and Fort Worth, gave me detailed information on the TRE's operations, including the load factors for each train.  Two variables caused me to wonder about the difference between their operation and a theoritical model set-up by a national agency to compare the efficiency of various modes of transport. The load factors on the TRE ranged from more than 80 per cent during the morning and evening rush hours to less than 10 per cent during the very early morning and very late evening trains.  The average load factor was in the neighborhood of 33 per cent.  So during the morning the TRE is probably more energy efficient than a large personal vehicle with only one or two passengers.  But during the off-peak hours, the efficiency factors change. Operationally, the TRE trains stand idle at the end of each run for 20 to 30 minutes.  The locomotives idle at a seemingly high rate.  I don't know how much fuel they are consuming whilst in idle mode, but it leads me to wonder how the analysts, who are attempting to determine the comparative efficiency of alternative modes of transport, factor this fact into their analysis.
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