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[quote user="ICLand"] [quote user="Bucyrus"] But it does not follow that a 300-ton train uses 1143 times the energy to travel 300 mph as a 1.5-ton car uses to travel 10 mph.       [/quote]  You can't. I tried to say that; it is only a very broad analogy. These are indexed and each is indexed to its own weight and inherent fuel consumption.  By and large, indexes cannot be compared to each other except in very broad terms; in this case the efficiency of energy use as the vehicle changes with speed. Both vehicles have relatively good efficiency at low speeds, and both are just awful at high speeds. That's a feature of speed, not the vehicle type. A car can't go very fast, so it retains a degree of relative efficiency. A HSR vehicle, to the extent that it is highly energy inefficient at the speeds it is designed to go, gains economic efficiency if it can obtain a ridership sufficient to overcome the inherent energy efficiency of slower speed modes. This is all compounded by cycle times because the car's slower speed adds a cycle time efficiency to the HSR's advantages. But, you are exactly right, these are not measures of energy use; they are measures of the efficiency of energy use.  Energy use is different for each vehicle type,  and so the use x the efficiency would be getting closer to what you are looking for. [/quote] As you say, you need to factor actual energy used per mile in a train versus in a car on the highway.  Without that information, there simply is no basis to determine, over a given distance, how many passengers an HSR train would need to carry in order to equal the efficiency of that same number of people using their individual cars on the highway. I don’t see how it even offers a broad analogy.  The only thing that the table illustrates is the rapid increase in energy needed for increasing speed.  But it offers no way to compare HSR to automobiles.
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