The Oscar winner, 36, was initially slated to play the husband of a woman, played by Haley Bennett, who goes missing, but Leto was unable to commit due to a scheduling issue, according to The Hollywood Reporter.
Evans joins a star-studded cast including Lisa Kudrow, Justin Theroux, Rebecca Ferguson, Allison Janney and Emily Blunt.
"The Girl on the Train", written by British author Paula Hawkins, revolves around an unemployed alcoholic (Blunt), who concocts a perfect life for a couple she comes across during her daily commuter train travels.