The poem has two principal genres, lyric and riddle. The poem qualifies as a lyric because it represents the personal observations of the unnamed speaker. The presentation of the train is neither objective nor scientific; rather, it’s subjective, reflecting the speaker’s idiosyncratic beliefs about trains and their relationship to horses. As the speaker never actually uses the word “horse” or “train,” the poem is a riddle. The reader must figure out that the speaker is describing a train with equestrian terms. To understand the connection, the poet uses diction—specific words like “lick” (Line 2), “neigh” (Line 14), and “stable door” (Line 17) suggest the animal, while terms like “Tanks” (Line 3) and “Quarry pare” (Line 8) indicate the machine. Even without the historical context, the poem thus provides the clues to solve the imputed puzzle. 

As with nearly all of Dickinson’s poems, although the speaker is unnamed and enigmatic, they don’t completely erase themselves or try to pass their imagery off as detached and dispassionate. The speaker wants the reader to know that they’re narrating the train’s journey, so the first word is the first-person, singular pronoun “I,” foregrounding the speaker watching the train before depicting the train itself. In other words, the speaker is the catalyst for the poem: What follows are their individual thoughts about the train’s journey. 

The poem often appears in anthologies for children, who presumably gain pleasure from figuring out the poem is about a train that the speaker sees as a horse. Dickinson often wrote poems for her younger cousins, so the biographical context supports an implied younger audience. At the same time, the poem features complex themes—the transgressive force of technology, its malleability and weaknesses, and the concealment of humanity—that indicates suitability for a broader audience. 

The poem begins with an ebullient tone as the speaker explicitly enjoys watching the train: “I like to see it lap the Miles— / And lick the Valleys

up—” (Lines 1-2). The alliteration, or close placement of words that begin with the same sound—here, “like”, “lap,” and “lick”—adds to the sense of rollicking pleasure. Dickinson also uses assonance, or close placement of words that feature similar internal sounds—a technique related to alliteration. Here, the exhilaration of E sounds in “see” and “Valleys” (Lines 1-2), “feed” (Line 3), and “prodigious” (Line 4) adds to the energy. The momentum is enhanced with elements of the description: “Tanks” (Line 3) provide literal fuel and the term “prodigious” highlights the train’s extraordinary power.

The train moves through “a Pile of Mountains” (Line 5). The “pile” reinforces the train’s forcefulness. The train isn’t only capable of getting around a single mountain, it can move around a series of mountains so easily that they do not present an obstacle. The word “Pile” connotes hastily strewn small objects rather than a range deeply embedded in the ground. Using personification, Dickinson gives the train human traits. Her speaker describes the train’s “supercilious peer / In Shanties—by the sides of Roads—” (Lines 6-7). Now, the tone is somewhat negative. The train is a snob that looks down on the unwealthy homes that it passes. The alliteration of S words creates a hissing sound that underscores the train’s contempt. Unlike the poorly built “Shanties,” the train is sleek, modern, and well cared for.

The speaker uses juxtaposition to highlight the train’s contrasting traits. The train is “prodigious,” but it’s also domesticated and weak. The train doesn’t blast through the mountains without assistance; rather, there’s a “Quarry pare / To fit its sides / And crawl between” (Lines 8-10). Only with human intervention is there space for the train to move, and even so, it must “crawl” like a baby or an undeveloped creature. Moreover, the train is “[c]omplaining all the while / In horrid—hooting stanza” (Lines 11-12); the noise implies that the train is whiny about the challenge of travel. The alliteration of H words echoes the fact that the train puffs like it’s out of breath or tired. It’s not immortal or indefatigable. It only regains vigor as it “chases itself down Hill—” (Line 13) since going downhill uses less energy. The idea of the train playing “chase” with itself suggests childlike glee instead of brute force.

The speaker returns to the train’s sounds. Using a simile, the speaker hears it “neigh like Boanerges” (Line 14)—a reference with multiple meanings. Boanerges is the last name Jesus gave to the apostles James and John, so the allusion has a spiritual tone. The train has the power of those heralding a deity, but it heralds the godlike power of technology. Boanerges also means “son of thunder” in Aramaic, a phrase that undescores the train’s striking force. 

The allusion to thunder brings in nature—a motif that the speaker advances with “prompter than a Star” (Line 15). The train is reliable; like a star whose appearance in the night sky is predictable and mapped. People can depend on the train to arrive and depart on time. The speaker spotlights the train’s conflicting “docile and omnipotent” traits (Line 16): It has the seemingly unlimited power to traverse any distance, but lacks authority to direct itself. The train isn’t its own master or boss. Like the apostles, it serves and follows others. Subordinate to the people who built it, the train is “docile.”

The emphasis on this dependence on its makers also comes through in the phase “it’s own stable door” (Line 17). (In Dickinson’s time, the possessive form of the pronoun “it” and the contraction for “it is” were not yet codified, so this is an archaic way of writing “its.”) Dickinson denies the train ownership and highlights its status as a tame creature akin to the horse. After it has performed its task, the train retreats behind the “stable door” created by its owners to wait until they need its services again.