Symbolism: Dickinson uses the train as a symbol of technological innovation during the Industrial Revolution.
Metaphor: The whole poem acts as an extended metaphor comparing a train to an animal.
Simile: The poem uses a simile to compare the train to Boanerges. Boanerges is the last name given by Christ to his disciples James and John. It means “mighty shouter,” as well as “sons of thunder.” In the poem, the train is described as a mighty shouter because of its powerful whistle.