It is easy to say that Snowpiercer is about the class systems in society and how when tension leads to revolution from those under struggle. But Snowpiercer it is how Snowpiercer visually portrays this is so successful. The train serves as a visual realization of the separation of classes and how the classes see the world around them.
Starting with the back, the lowest of the low is in the back and it is not surprising that they have no windows. They are in darkness and shambles. The back solely lives with the intent of survival. They are not truly living but merely surviving day to day under the order of those in power. They are forced to view the back of the train as their whole world because they have no connection to anything other than that. This world building is not surprising as the realistic view of those in poverty their worlds are similarly very small. It is the world building that Bonn Jong-Ho uses that sets up the comparison between worlds. When we get to the front of the train we are faced with a similar world. Sauna rooms, rave and drug rooms that have no windows either. These people are also living in a world just as small as those in the back. Their visual understanding of survival is so limited that they know nothing else. This lack of understanding of the fuller picture is emulated in Curtis, who being from the back has no understanding of the bigger picture. He is constantly faced with decisions that either move him forward or backward.
It is only when Namgoong confronts him with the possibility of the outside that Curtis even realizes a different direction. His world though has been so limited by confinement to the back of the train, though, that he cannot even comprehend this as a possibility. It is only Namgoong, who is from the middle of the train, who can realize the exterior world because he has not been limited to the visual of just the train. It’s the middle of the train that is fully saturated with a range of colors and space that we are released from the confinement of the back and can expand. It’s in this world that Namgoong came and it’s this world that he realizes to be true. It’s this middle class that has the power to realize the potentials of the world. If it is possible in this world that the middle can see differently and drastically to create change then is it possible in our own world that this is true. Does the middle have the power to be separated from the brainwashing and comfort to realize the issues and to make the change?