Shinkansen Henkei Robo Shinkalion: Mirai kara Kita Shinsoku no ALFA-X

A research group called the Shinkansen Ultra Evolution Institute is investigating monster attacks in Japan following the emergence of a mysterious Black Shinkansen. Their primary defense is the Shinkalions, bullet trains capable of transforming into large mecha. Hayato Hayasugi, a train enthusiast, discovers his father's involvement with the SUEI and unexpectedly becomes a Shinkalion driver. Alongside other children, he bears the responsibility of defending against otherworldly threats. A new enemy from space arrives with plans to conquer Earth. The SUEI deploys a new prototype, the ALFA-X, but Hayato’s father, Hokuto, vanishes. A nine-year-old version of Hokuto travels through time to the present to assist in the battle, piloting the ALFA-X.