But to travel at 800 mph without making your passengers sick and barfing, the route actually needs curves to be 16 times as smooth as the 200 mph CHSR.
Some critics of the Hyperloop concept have focused on the possibly unpleasant and frightening experience of riding in a narrow sealed, windowless capsule, inside a sealed steel tunnel, that is subjected to significant acceleration forces, high noise levels due to air being compressed and ducted around the capsule at near-sonic speeds, and the vibration and jostling created as the capsule shoots through a tube that is not perfectly smooth or level. Even if the tube is smooth upon construction, ground shifting due to settling and ongoing seismic activity will inevitably cause deviations from a perfectly smooth, level path. At speeds approaching 900 feet per second (270 m/s), even 1 millimeter (0.039 in) deviations from a straight path would add considerable buffeting and vibration. With no provisions for passengers to stand, move within the capsule, use a restroom during the trip, or get assistance or relief in case of illness or motion sickness, the potential for a seriously unpleasant travel experience would likely be higher than in any other popular form of public transport.