Source Code is fantastic! (boxed spoilers)

In the Original Timeline the train blew up in the morning so everyone was looking for the bomber. In the final timeline, where he completely takes over the other guy’s life, the would-be bomber is just a briefing for the Source Code manager.

That doesn’t really hold up. In the original timeline, the authorities seemed to think it had been a suicide bomber, so they would be looking for his accomplices. Also, how in the original timeline did the authorities know that there was a dirty bomb heading for Chicago? As far as I can tell, those are left as loose ends… and I rewatched the scene with the swat team manhunt on TV twice, and it does seem to very strongly imply that the information concerning the suspect’s identity has been known for some time, although of course it might just be the editing.

I think they mentioned getting a tip after the train blew up that a dirty bomb was going to blow up in Chicago.

As for all the stuff on the news, that’s just Hollywood. I wouldn’t be surprised if there was a trope page for “The news knows everything.”