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Why are maglev trains still rare?
(lemmy.ml)
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this post was submitted on 08 Sep 2023
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The same reason supersonic passenger jets are rare.
The extra speed comes with a massive increase in costs.
Travel 30% faster than high speed rail for 10-20 times the cost.
Is the claim about "10-20 times the cost" true? The internet says Shanghai maglev cost $1.33 billion for 30.5 km, i.e. less than $44 million/km. Compare https://transitcosts.com/new-data/ or https://transitcosts.com/high-speed-rail-preliminary-data-analysis/
Secondly, if it is true, why would it be true? Why would it be more expensive to build something with fewer moving parts?
Supersonic passeenger jets require more energy. Maglev trains require less energy.
all the other complex and important factors aside, air restistance is a formula of speed squared. Meaning for example if you bump speed up by 40% you double air resistance, and therefore double the energy cost of transport.
Isn’t that only applicable for identical trains? For sake argument, if you had two identical trains designed with poor aerodynamics, one at 100mph and one at 140mph then you can double the energy cost. But if you take two different trains with one designed to be more aerodynamic, at the same speed they wouldn’t have the same energy cost as the second has a better profile?
Plus theres less friction from needing to be on a rail.
So I think saying its double the cost of transport is too simplistic to be meaningful in this discussion
It's more than that - doubling air resistance only doubles the energy use if it's the only inefficiency on the train (e.g., no losses in the magnets, HVAC, lighting, etc.). Add onto that the fact that you're basically eliminating rolling resistance from traditional trains when switching to maglev, and the expected outcome should be much less than double.
Finally, the most important part, each high speed rail route of any meaningful distance has the opportunity to displace a certain amount of air travel, so big picture, HSR results in a significant decrease in overall energy consumption.
Is that factoring in the always on cooling of the magnets?
Here's an article about the subject, paper linked at the bottom of the article: https://phys.org/news/2010-12-high-speed-pollute-percent-traditional.html
Thx, as I understand it, this is calculated for traditional railway technology and does not have anything to do with to maglev.