Off the Rails tells the story about a man, whose Asperger's diagnosis makes it difficult for him to stop his lifelong obsession with driving trains. Darius would just take trains straight from the yard and drive them with perfect knowledge of the system and all the stops. However, despite his mass knowledge of the system, the transit authority refuses to employ Darius because of his history of hijacking, even though he has never once harmed anyone.
Off the Rails is an example of the extremes having Asperger's Syndrome can take someone. Darius McCollum prefers things over people, particularly after a rough childhood, where he was a victim of bullying in school and was even stabbed by a fellow student. Darius never received proper therapy for his Asperger's and was often treated more like a common criminal by authorities, rather than someone with mental health issues. While there is an overall lighthearted tone to Off the Rails, the film has a sad undertone, since this man's life is controlled by his obsession.