Given that the proposal describes dampers used to absorb change, I think this is wrong.
By building a system on pylons, where the tube is not
rigidly fixed at any point, you can dramatically
mitigateEarthquake risk and avoid the need for expansion
joints. Tucked away inside each pylon, you could place
two adjustable lateral (XY) dampers and one vertical (Z)
damper.
These would absorb the small length changes between
pylons due to thermal changes, as well as long form
subtle height changes
The tube will be supported by pillars which constrain the tube in the vertical direction but allow longitudinal slip for thermal expansion as well as dampened lateral slip to reduce the risk posed by earthquake.
It says dampers absorb change. But it doesn't mean only dampers do that. Of course they couldn't handle hundred meters expansion (near ends). I don't believe Musk would make such an easy mistake and force dampers handle all of thermal expansion.
That said, the quoted text is somewhat confusing. I had to read it a few times before I got the idea.
