Directed by Antonia Bird (who has a penchant for making movies on explosive subjects), the movie dramatizes the study of September 11 hijackers. Based on a 2 year long research by Alice Pearman, the director says "I cant think of a single incident in a film that hasnt come from evidence and research". The telegraph seems to think that the film is a good peice of work. See their article.
A little digging on the net revealed why the name was chosen. Washington post in one of its articles - "Encounter on a Train Led Hamburg Cell to Bin Laden" details how a chance meeting on a train in germany in 1999 changed the target of a certain group (the hamburg cell) from Chechniya to the US.
Personally, all this has made me very eager to see this film - sounds promising !