Everyone Is Waiting - S1.E12

After seeing the others back to Tokyo while they cleaned up the aftermath of the Hokutosei incident, Naoto and Iida wait at Aomori Station. The engine that will pull their train to Tokyo is the KiHa 381, equipped with a pendulum-style, diesel-fueled gas turbine engine. Shortly after they depart, Naoto hears a strange sound and can't shake the feeling that something isn't right.