Toaru Kagaku no Railgun SS: Dasoku, Mata wa Toaru Jiken no Shūmaku (とある科学の超電磁砲SS 蛇足、またはとある事件の終幕 lit. "A Certain Scientific Railgun SS: A Superfluous Story, or A Certain Incident's End"?), also referred to as Toaru Kagaku no Railgun: PSP SS, is a short story by Kamachi Kazuma which was included with the Toaru Kagaku no Railgun PSP: The Complete Visual Guide. It is set shortly after the events of game, and focuses on Misaka Mikoto and Aizono Mio joining forces to find the latter's teacher, Saitou Souta.
By order of appearance:
- Electromaster (Railgun variant) - Misaka Mikoto (Level 5)
- Military Oil - Aizono Mio, Hyoudou Maki, Wajiku Kobina, Sakasama Yuri, Yoake Sayori (Level 4)