Director Bong Joon Ho often clashed with producer Harvey Weinstein, who frequently interfered in order to create "his" version of the film. Among the many requests, the producer insisted of having the fish scene removed in favor of more action. Bong, who considered it his favorite shot in the film, was adamant to keep it in. He told the producer that he wanted to keep the shot for a personal reason, as a tribute to his late father, who was a fisherman. Upon hearing this, Weinstein said that family is very important to him, so he granted Bong to keep the shot. In an interview, the director said "It was a fucking lie. My father was not a fisherman."

There was no additional lighting used while filming the torchlight fight scene.

Writer and director Bong Joon Ho explained that the protein block was made by combining seaweed, tangle, sugar, and gelatin. Jamie Bell hated it, while Tilda Swinton liked it.

Writer and director Bong Joon Ho had reservations about casting Chris Evans in the lead role, because of his muscular physique. He felt that as a resident of the extremely poverty-stricken tail section, Chris should not be especially physically fit. Costuming and careful camera angles kept Evans' physique from showing.

Sir John Hurt's character's name, Gilliam, is an homage to Terry Gilliam, a director whose filmography includes similarly bleak science fiction, fantasy, and end-of-the-world titles, such as Brazil (1985), 12 Monkeys (1995), and The Zero Theorem (2013).

According to the filmmakers, train babies like Yona (Ko Asung) developed animalistic hearing skills.

The drawings in the tail section of Snowpiercer were illustrated by Jean-Marc Rochette, the original comic artist of the graphic novel Le Transperceneige.

Bong Joon Ho first wrote the part of Mason with John C. Reilly in mind, but then adapted the character for Tilda Swinton, though he intentionally left lines of Mason being referred to in the masculine form in the script, which show up in the movie.

Chris Evans personally contacted Bong Joon Ho for the audition after hearing the casting news.

This is based on the French graphic novel "Le Transperceneige". Bong Joon Ho discovered the comic in late 2004, during pre-production of The Host (2006), and was fascinated by the concept of people struggling on the train for survival.

The glasses that Mason was wearing were originally Tilda Swinton's. When writer and director Bong Joon Ho visited her, they played with her children's play box and found them.

Barrandov Studio was chosen for the production. The studio completed construction of a one hundred meter (three hundred twenty-eight feet) long replica of the train.

Writer and director Bong Joon Ho wanted to underline the pressing danger of global warming by setting the year that CW-7 is dispersed as 2014.

Filmed in 72 days.

The last scene was shot in Austria.

This is Bong Joon Ho's first English-language movie.

Jamie Bell's character, Edgar, was named after director Edgar Wright.

Tilda Swinton had to spend more than two hours in the make-up chair.

Kang-ho Song and Ko Asung also played father and daughter in The Host (2006).

Writer and director Bong Joon Ho said the fish scene was inspired by The Godfather (1972).

Mason was originally a male character and described as a "peaceful" one in the original script. This changed when Tilda Swinton was cast.

Jake Gyllenhaal and Dustin Hoffman auditioned for this movie.

Emma Levie was a Dutch college student that Bong Joon Ho contacted after seeing her in Lena (2011). Levie was surprised to see celebrities Chris Evans and Ed Harris when she came to the set.

This is the third dystopian themed movie for Sir John Hurt, after 1984 (1984) and V for Vendetta (2005).

The concept of Teacher (Alison Pill) being pregnant came from Ko Asung.

Bong Joon Ho says he got the idea from a 1970s nuclear-powered submarine. The train and nuclear-powered submarine in the 1970s had a similar average speed of fifty kilometers (thirty-one miles) per hour.

Sold to 167 territories ahead of its theatrical opening in 2013, it's production company CJ Entertainment's biggest sales success. (2016)

This movie takes place in 2014 and 2031.

The song "Midnight, the Stars, and You" was also played in The Shining (1980).

The cast features two Oscar winners: Tilda Swinton and Octavia Spencer; and two Oscar nominees: Sir John Hurt and Ed Harris.

The premise bears similarities to the premise of "The Second Renaissance" segment of The Animatrix (2003). Both movies show humans causing their own downfall by releasing an airborne gas into the atmosphere, only in The Animatrix (2003), it was to block the machines' power source (the sun). In this movie, it is released to stop global warming.

This is the second movie featuring Chris Evans which featured Earth frozen in another ice age, after Sunshine (2007).

Jamie Bell and Chris Evans played members of the Fantastic Four. Evans played The Human Torch in Fantastic Four (2005) and Fantastic 4: Rise of the Silver Surfer (2007), and Bell played The Thing in Fantastic Four (2015).

Chris Evans and Alison Pill appeared in Scott Pilgrim vs. the World (2010).

Kang-ho Song, Ko Asung and Paul Lazar appeared in Bong Joon Ho's The Host (2006).

John Hurt (Gilliam) and Tilda Swinton (Mason) appeared together that same year in Only Lovers Left Alive (2013)

Song Kang-ho, Ko Asung, and Paul Lazar appeared in Bong Joon-ho's The Host (2006).

According to the filmmakers, the Revolt of the Seven's female leader is Namkoong Minsoo's (Kang-ho Song's) wife and Yona's (Ko Asung's) mother.

According to writer and director Bong Joon Ho, Tilda Swinton played another role, as well as Mason. She played the woman trying to snatch the wine bottle from Yona when she and her dad are collecting Kronole lumps from the clubbers.

Wilford says to Curtis that he's the only person to ever walk the length of the train from tail to engine. This isn't true though, as both Timmy and Andy (and presumably other children before them) have also made that journey.

Writer and director Bong Joon Ho couldn't find the perfect actor for Wilford until producer Chan-wook Park recommended Ed Harris.

The North American movie poster "foreshadows" Curtis' (Chris Evans') fate. Curtis' lower left arm is obscured in the poster. He loses that appendage during the climax of this movie.

The markings on the engine, a circle with a narrow "S" on it, represent the yin yang, the same relationship between the front and the back of the train. The front can't survive without the children of the back, and the back can't survive without the food from the front, a "perfect" symbiotic relationship.

Octavia Spencer (Tanya) shot her last scene without any movement until the shooting ended.

When after the first fight, when Gilliam & Curtis are resting side by side and Curtis says that he's not sure if he's the right person to lead Gilliam mentions that "we are not even half way through it". In the film this is just before the midpoint (at around 1 hour 23 seconds) with around 1 hour 6 minutes remaining.