The train needs to be in constant motion, which happens due to its perpetual engine (as seen on the blueprints in the opening sequence) called the "Eternal Engine". If the train were to stop for more than thirteen minutes, everyone would freeze to death.
Based on the 1982 French graphic novel Le Transperceneige, later retitled Snowpiercer, written by Jacques Lob and illustrated by Jean-Marc Rochette.
Was renewed for a second season a year before the first season even aired, as the show was originally set to air in 2019, but was delayed to 2020 due to its move from TNT to TBS, a move that was later reversed.
The train consists of first, second and third class and the tail, and the engine at the front. Passengers in the tail had no tickets and entered the train by force upon departure. It is mentioned several times that 400 passengers are in the tail, and that they are allowed to stay in exchange for working. Third class passengers did not have to pay for their tickets, but have to work. First class passengers did pay for tickets, one mentioned to have paid 400 million. The engine is for engineers and Mr Wilford.
TNT released a timeline for the Snowpiercer saga, citing that the series took place seven years following the extinction event, while the movie takes place seventeen years post-extinction. This means that, despite the show being based on the movie, the events of the show predate the movie by ten years.