Sangaku Youko (山岳 揚子 Sangaku Yōko?) is a driver.
- Main article: Toaru Kagaku no Railgun: Uiharu SS
- She was named as Sangaku Tatsuko (山岳 達子?) in the side story's original publication but changed to Sangaku Youko in the Toaru Majutsu no Index SP reprint.