A second season, A Certain Scientific Railgun S, aired in Spring 2013, focusing on the Railgun version of the Sisters Arc and an anime-original plotline.
A Certain Scientific Railgun is a manga spin-off and to the A Certain Magical Index series written by . Similar to the original, it has received an courtesy of , which covers the first major arc of the manga as well as some anime-original material penned by the author. In addition, there are side-story novels which involve the protagonists with the Magic side.
Among Funimation’s newest releases, A Certain Scientific Railgun (To Aru Kagaku no Railgun in Japanese), stands to provide fans of A Certain Magical Index some extra story in the fictitious Academy City. Released only on DVD and available online to Funimation subscribers, Railgun is a 24 episode series that attempts to tell the story of Misaka Mikoto, a high-ranked “Esper” (series jargon for individuals with psychic powers) as she attends school in Academy City, a highly advanced metropolis designated specifically for Esper students.