(at around 1h 8 mins) When Nana goes with the train driver to find Noriko towards the end of the film, the number of the train is "507". In Japanese, "5" and "7" are pronounced "Go" and "Nana" respectively.
This was the first Japanese film that was released in Korea before Japan.
The movie was adapted into manga as well as a novel.
The Miskatonic University from the Cthulhu Mythos is referenced in the scene when Nana Kimura is reading a book and the university is featured on one of the pages.
The movie is based on a true story involving a woman named Yaeko Aonuma, who was killed in a train accident in Mizunashi, 1971.