From what I remember, Railgun a series of side-stories that happen before index's arrival. I would imagine that Touma won't be on such good terms with Misaka, especially after that Aztec Priest incident. Their encounter in episode 1 hinted that they knew each other though, enough that Touma knew when some thugs would get their asses owned if he didn't lure them away.Originally Posted by Nadouku
At that, I'd imagine Touma would play a part, albeit a more minor one.