The Toaru Kagaku no Railgun S official visual book will include a Blu-ray OVA titled "Daiji na Koto wa Zenbu Sentou ni Osowatta" (All Important Things Have Been Learned in the Hot Bath) and will be released on March 27, 2014. There is no further information at this time, but the title suggests the story will take place at a hot bath (sentou).
(MAL)
Овашка. "Рельсы". Про сэнто.

Кое-кому пора запасаться сырой печёнкой.