During the commentary she did for the DVD of What Makes Sammy Run?: Part 1 (1959) Dina Merrill said that the treatment she received from director John Frankenheimer on this picture nearly drove her out of the business. He told her at the end of a day's filming that she was the worst actress he'd ever worked with. She said she went home in tears. It got so bad that her co-star Burt Lancaster came to her defense one morning by ridiculing the director's "good mood" as evidenced by the fact that he hadn't insulted Dina yet.
Burt Lancaster was forced by United Artists to make four films for $150,000 a picture in the 1960s: The Young Savages (1961), Birdman of Alcatraz (1962), The Train (1964) and The Hallelujah Trail (1965) rather than his normal fee of $750,000, because of cost overruns at his production company, Hecht-Hill-Lancaster, for which he was personally responsible.
When Burt Lancaster walked onto the set the first day of shooting, he was startled and dismayed to see the camera on the floor, aiming upward. Lancaster had never before worked with a director who used such innovative camera angles. He grew to trust John Frankenheimer, and they made four more films together.
Burt Lancaster and Shelley Winters, who played former lovers in the film, were actually former lovers in real life.
Shelley Winters was a late replacement for Lee Grant, who had already filmed a key scene when she quit.