philadelphia. you spoke with a close friend of brandon bostian. you asked him all the tough questions. what did he tell you? >> reporter: he says there must be more to the story than what we're hearing if it's the brandon bostian he knew. aifier bishop was a flag man on the route and he worked with brandon on hundreds of trips up and down this corridor. he says he never saw anything that would alarm him. >> good engineer. great engineer. he was on point. if there was something he didn't know he knew who to call to get the information. he didn't come off as a know it all and he knew everything. he knew what he needed to know and if he wasn't 100% sure he was going to call and make sure that he got the proper information. he wasn't going to do anything and okay i'm just going to assume that something was going to happen. he was always thorough. >> you mentioned we all know the speech we all know the trip the route. you know that that curve is