this post was submitted on 24 Feb 2024
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Futurology
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Some people are skeptical this technology can ever work, but it appears CASIC's Phase 1 testing in a 2km tunnel has given them the confidence to proceed to Phase 2 testing in a 60km long tunnel.
Chinese railway engineering leads the world so I have a hunch that if any nation can pull this off, then it's China. However, lots of questions remain. A back-of-the-envelope calculation says that to achieve those speeds in the 2km test tunnel deceleration would have been about 3G. That's the same as a rocket at lift-off and not many people's idea of comfort.
I got an acceleration of 1.5G for the test, did you forget a factor of 2 or something? Still certainly not an enjoyable experience for passengers, but I assume it would accelerate over a much longer distance if a full track was built.
I think I'd probably be fine with 1.5Gs as long as the jerk and snap were low.
Adding in Earth's gravity it's about 1.8G total, applied at a weird angle, which might be too much for some people.
Did you also factor in that the train needs to come to a full stop in that 2km as well?
Yes, I calculated the acceleration required to accelerate to 387MPH (173m/s) in 1km.
v^2 = 2ax
(173m/s)^2 = 2a(1000m)
a = 14.96m/s^2 = 1.53g