Based on a true story, "Train Man" will recount the life of McCollum, diagnosed with Asperger syndrome, who developed a life-long obsession with New York's subways and trains, said The Hollywood Reporter.
Frequently arrested and imprisoned, he became a cult figure around the city after wanted posters warning passengers about him appeared throughout the city. Roberts will play McCollum's long-time attorney Sally Butler.
Interestingly, Roberts won an Oscar for playing a tenacious law firm clerk in 2000's "Erin Brockovich".