An experiment to end climate change fails, freezing the planet. A few escape onto a self-sustaining train. A vicious class system oppresses the proles, who revolt. Yes, the ruling class on the train needed their corrupt, pampered asses kicked hard. However, without being a spoiler, I will say, violent revolution can have unintended consequences. Be careful of who you are with and what you ask for.
Set in a future where a failed climate-change experiment kills all life on the planet except for a lucky few who boarded the Snowpiercer, a train that travels around the globe, where a class system emerges.