Edit: HS2 in Britain, for instance, is being designed with a maximum of around 0.01g vertical acceleration. If Elon's has figured out how to get passengers to handle 50x that much, he could save them a lot of money.
Some other figures I could find:
Shinkansen: 2.6 km/h/s = 0.07g
ICE (German HSR): 0.5 m/s2 = 0.05g
S-Bahn (metro transport): 1 m/s2 = 0.1g
Makes sense that metro transport has higher acceleration, as high speed rail spends a lot of time "cruising" at certain speeds, while metro transport is basically always either accelerating or decelerating. I'd guess subways also feature relatively high g-forces.
Also interesting: http://en.wikipedia.org/wiki/Orders_of_magnitude_%28accelera...
Admittedly I have not tried it but I don't think that would work.
How much you can spin the seat without those movements causing problems is an open question.
Airplanes are an encouraging precedent. They often make quite sharp turns at extremely high velocity, but tilt into them such that there's almost no perceived lateral acceleration.
However from the article chart, there would be more than 50 peaks at +/-0.5G in 35 minutes, that would definitely feel more like a huge roller coaster ride than anything else, so my bet is that it's just unbearable except for astronauts and fighter pilots.
He says: "However, I only used this information for plotting. For this first study, the derived route is only 2-dimensional."
And the graph's acceleration is noted as longitudinal and lateral. Not vertical at all. The word "vertical" appears nowhere in the article. All of the pictures show 2D diagrams of routes.
I don't know where this sub-thread about vertical acceleration came from.
A banked turn transforms lateral acceleration into vertical within the passengers' frame of reference.
1. Presumably, if lateral acceleration proves to be preferable to vertical acceleration, you just turn off the banking.
2. You control the precise amount of vertical acceleration by the size of the bank, so if there's some amount of vertical acceleration that's desired and some that isn't, you only bank hard enough for the desired acceleration. You also to at least some degree control the jerk (change in acceleration) so you can smoothly slide into the acceleration change as you bank slowly harder.
3. Importantly, this is only increased-acceleration in local "down," not decreased acceleration in local down. I don't have any scientific data to back this up, but it's the drops (ie, reduced vertical acceleration compared to gravity) that seem to nauseate people on roller coasters, not the climbs.
But most importantly, I think that people were badly misinterpreting this article (not the original hyperloop paper) in thinking that its charts were about vertical rather than lateral and longitudinal acceleration.