The rebels learn that they are eating something not entirely appetizing, and though the secret of the food supply is not the same as the one revealed Soylent Green, the nature of the revelation is similar. The people are being sustained and nourished by a dreadful, disgusting source. In both cases, we also witness a sort of industrial process by which the awful food is prepared, out of sight of the consumers. The masses are being fed by the elite, but what they are being fed is monstrous.
Near the end of 2001, Bowman (Keir Dullea) travels through a mysterious Stargate and ends up in a world made for one. He sits alone, eating from fine China and drinking wine, on the verge of his evolution into something greater than mere human. Around him, he sees signs of a technological world (a glowing tiled floor) and a traditional one (decorated like a Victorian sitting room). This is appropriate, because his going to carry the legacy of humanity into his new form, as the Star Child.
Each new open door means an entrance into a different world. Sometimes, the new world is awe-inspiring (like the aquarium car), sometimes it is nightmarish (like the school room with a gun-toting teacher and the brainwashed students), and sometimes it is just bizarre, like the hedonistic realm of the elite, lost in their drug-filled reveries.
This story structure -- a new world opened with each new door -- is what specifically reminded me of Dante, and his famous, literary tour of Hell, where readers met sinners of every variety known to man. With some imagination, the train in Snowpiercer fulfills the same function, especially when Curtis reveals -- in heart-wrenching terms -- his own terrible personal sin.
This is truly a train of the damned, in more ways than one.
There's an element of the film that concerns how idealism gives way to practicality, or -- again -- entropy. We all believe that we will be generous and equitable when we "get to the top," but is that true? You don't really get to the top unless you're willing to step over a few backs.
Similarly, the film suggests there is an idealism inherent in"storming the train" that doesn't necessarily survive to the difficult task of "governing" the train. When you're starving, you just want to eat. It's a simple goal. When you have responsibility for a thousand lives and an eco-system, however, there are trade-offs, and other things to consider.