Neeson revealed on a talk show that no scenes were filmed on board an actual train. Instead, all of these scenes were shot on a soundstage, with the same single mock-up train cabinet serving as all of them, only slightly redressed, and all the outside scenery added in post production with the help of green screens.
Despite receiving the prominent second billing, Vera Farmiga has only about 6 minutes of screen time.
The sixteen personalities that Joanna refers to when she strikes up the initial conversation on the train are the Myers Briggs types.
Towards the beginning of the film when Neeson's character is walking through Grand Central Terminal, there is a poster for Paddington 2, which shared its US release date with The Commuter on January 12th.
In a 2018 interview with HeyUGuys, Jaume Collet-Serra spoke about the difference between shooting this film and 2 of his previous films that mostly take place in a single location: "It's harder because with both Instinct de survie (2016) and the plane (Non-Stop (2014)), you don't really get a sense of movement. The plane, you have tiny windows, at night, you don't get the sense of movement. And in The Shallows, you're stuck on a rock. But here, a train with big windows, the environment is constantly changing, the light is constantly changing and you have to plot that out. We shot the movie in London, so we were not on an actual train, we were on a stage. So you really have to have this complicated lighting system that has to match what you're gonna have later in the plates and it has to go along with the arc of the story. So that's technically difficult, if it wasn't difficult enough to shoot the movie in a train without a train."