Criticism of Hart Crane's American epic The Bridge has long focused on technological tropes. Readings of the subway's importance within the poem, however, tend to foreground the oppressive aspects of that space. This essay, by contrast, argues that New York's transit infrastructure enables Crane to re-imagine formal possibilities in the modernist poem. "The Tunnel" shows commuters ultimately making sense of their fragmented perceptions through routine and habit. The abstract subway system, the poem suggests, is only knowable through an accretion of partial information that comes from regular rides. This mediated relationship of part to whole plays out in Crane's poetics, suggesting a new way in which we might understand how mechanized routine and urban space shapes modernist literary form.