Back in the 70's when I was doing high speed passenger train cost studies for FRA, I got into that subject in some depth
There are three components of resistance in a train
- rolling resistance
- Wind resistance
- weight
Rolling resistance (journals, track, etc. varies directly with speed. Wind resistance varies as the square of the speed, but varies greatly with the shape of the vehicle. Weigth comes into play on grades, but in the long run averages to about zero.
Using conventional passenger equipment, the wind resistance was using about half of the pwoer at 60 mph. So if total resistance at 60 mph was 100, then wind was 50 and rolling was 50. At 80 mph it would be (80*80 / 60*60) * 50 for wind and (80/60) * 50 for rolling. That is a total resistance at 80 of 156,, a 56 % increase. At 100 mph, it's a 122 % increase in energy.
The steamline profile of HST raises the point at which wind is 50% of the resistanced so the numbers are a bit less drastic but still very significant.
The fact that French and German railways are using 180 mph on new lines indicates that the power cost is not unacceptable, but they have the very high population density and less effective road competition that is needed to get the huge number of riders to pay for the tremendous infrastructure expense. That's more important than the power question.
