The answer changes when you move with the speed of an airplane. Tracks even modestly dislocated by tremors would spell disaster. So a network of seismographs reads earthquake information and relays it by satelite to the train. There are no communications lines to be cut by earthquakes. That way, grades are kept under two percent.
Tracks have to bend very gently.
A typical radius of curvature is two and a half miles or more. Now the train slows into Tokyo station. We dismount in a swirl of people and disappear into the Tokyo subway system. Japan has picked her technological targets and aimed well. She builds exceptional cars and trains, but not airplanes.