> To say nothing of the fact that some of those precast tubes are going to be precast straight, and others precast curved. They're not interchangeable.
I don't know enough about steel and construction, but I think the tubes could all be made straight. Hyperloop curves have very large turn radius. Steel tubes are not completely rigid, they can curve a little by themselves.
Fair point - maybe that would allow the necessary flex.
The minimum bend radius they allow for the 300mph segment is 3.67km. If you made a complete circle it would have a circumference of 23km, and comprise 769 30m segments. Each segment would need to contribute 0.46deg of the 360deg curve.
To achieve this over 30m you need to deviate the end of the pipe by 24cm from where it should be... which actually sounds like a hell of a lot to me, especially if it's flexed through this range regularly (as it would be if constantly switching places with a truly straight segment).
I don't know enough about steel and construction, but I think the tubes could all be made straight. Hyperloop curves have very large turn radius. Steel tubes are not completely rigid, they can curve a little by themselves.