Talk:Anime Timeline/@comment-66.90.213.131-20130813074328/@comment-125.60.240.201-20130813075627

In the original manga, Mikoto met Touma an entire month before the Level Upper Arc. This is shown in episode 4 of Railgun in the little flashback with Touma trying to save Mikoto from the thugs not knowing who she is. We can assume that Mikoto has been running around and trying to catch Touma between their meetings and the events of the Level Upper Arc, as is the reason why Mikoto knows him.

Level Upper Arc, and by extant the start of Toaru Kagaku no Railgun, happens long before Toaru Majutsu no Index (the Index Arc) in the Railgun anime since the anime magically decided to extend summer vacation. But the Railgun manga does not have this problem as the Index Arc happens during the later events of the Level Upper Arc.

Railgun S happens directly after Railgun season 1 but most of the events of Railgun S happens before Touma's involvement in the Sisters Arc.