A side story of To Aru Majutsu no Index
, manga "To Aru Kagaku no Rail Gun
" was announced to get an anime adaptation. The notice was aired at the end of the final episode of To Aru Majutsu no Index aired on AT-X channel. The detail of the anime will be given in Dengeki Daioh May issue to be released on March 27th.
Source: Screenshot of the announcement
Source: Dengeki Daioh
According to Dengeki Daioh, the anime will start in October.
Source: Scan of Dengeki Daioh