Now experts are trying to figure out what went wrong with the Tohoku Shinkansen Hayabusa-Komachi No. 6. The mishap occurred shortly after 8 a.m. on Sept. 19. “I felt it stopping silently.

(JR East), a passenger aboard the Hayabusa No. 52 pressed an emergency call button around 11:55 a.m. when the train was about to stop at Sendai Station. A crew member contacted the Shinkansen ...