The Train (Allegory)
The train itself is an allegory for the world and society at large, the way that it is stratified by such strict class delineations that privilege the wealthy and hurt the poor. The train, an industrial marvel hurtling through an unfriendly wilderness, represents both humankind's ingenuity as well as its faults. While the train provides shelter for the citizens aboard, it is run by an oppressive leader with a megalomaniacal belief in his own sense of what is right for his citizens. The entire premise of the film can be read as a political allegory for fascist governance and the exploitation of the poorer classes.
Wilford (Symbol)
Wilford, as the conductor and creator of the train, a beloved figurehead for the citizens, is not seen until the very end of the film. Until we see him, he is a kind of symbol, a representation of the hope that the passengers are meant to have, and the ways they are supposed to believe in the oppressive structures that dictate their existence. He is an almost godlike figure, and the passengers on the train are brainwashed into believing he is their savior. To Curtis and the other revolutionaries, he is a symbol of oppression and inequity, a representation of the ways that human beings abuse their power.
Curtis' Arm (Symbol)
Curtis puts his arm in a gear in order to help Timmy crawl out of the engine at the end of the film. He knows his arm will be cut off when he does this, but he does it anyway in order to save the child from his enslavement. It represents Curtis' sense of duty and sacrifice. Earlier in the film, he spoke of regretting the fact that he has not made more sacrifices for the good of the tail passengers, and here, he takes an opportunity to make a huge sacrifice in order to stay true to his word to Tanya, Timmy's mother.
No Eyes (Symbol)
At one point, the revolutionaries are caught in an ambush and they are faced with masked men carrying axes and other brutal weapons. The only holes in the masks are on the guards' mouths, with no place for eyes to see. The fact that these fighters do not have eyes represents both a literal and an ethical blindness. Blindly following Wilford, they cannot even see the figures they are trying to kill. Rather, they chaotically spread violence wheresoever they go, exacerbated by their inability to see.
Violence (Motif)
The film is saturated with near-constant violence. In the beginning, the soldiers who oversee the tail car demonstrate that they are violent men when they ask if there are any violinists on the train and they beat up the old woman who doesn't want to be separated from her husband. This is the first moment the viewer sees just how brutal the authorities are. Once the tail car passengers stage their revolution, the violence becomes even more heightened, often brutal and terrifying. At the end, Wilford says that he only wants to keep order on the train so that violence does not need to happen, yet he is the one who has created the violent structure in the first place. By portraying violence so unflinchingly, the film pulls the viewer into the reality and priorities of its characters and shows the ways that hierarchy and inequality lead to such brutality.