This poem, although the subject is never named explicitly, only referred to as “it,” is about a train. The speaker enjoys watching this train traveling through the country (“I like to see it lap the Miles –“), imagining it as a kind of giant horse figure, going fast and far and licking up the country side (“And lick the Valleys up –“). She imagines it feeding itself at tanks—ostensibly, either filling with new passengers at train stations, or being refueled (“And stop to feed itself at Tanks –“).
Its size and might are such that it can take a giant (“prodigious”) “step / Around a Pile of Mountains –.” Because of its pride in its own great power and speed, it looks in arrogantly when it passes shacks (“And supercilious peer / In Shanties”) that are along the road (“by the sides of Roads –“). So too can it cut into a quarry as if it were a fruit (“And then a Quarry pare”) so that there is room for the tracks (“To fit its Ribs”).
When it must “crawl” more slowly through a tight space, she imagines its sounds (“In horrid – hooting stanza –“) are those of “Complaining.” Its sounds are prouder, louder (“And neigh like Boanerges –“), when it can move faster (“chase itself down Hill –“). Finally, it punctually stops at its resting place (“punctual as a Star”), and becomes completely quiet, although it is still powerful (“docile and omnipotent / At its own stable door –“).
“I like to see it lap the Miles –“ highlights Dickinson’s taste for riddles—they recur almost constantly in her poems. Although this is certainly not one of her most difficult ones, the whole poem is framed as a riddle—what is this horse-like creature that can “lick the Valleys up—?“ The riddle in this poem is not just there for its own sake, however; it emphasizes the disconnect between this mysterious creature and the natural world it inhabits and imitates.
Dickinson gives the train agency in the poem—it laps, it licks, it feeds itself, it crawls—and emotions—it is supercilious, it complains. In doing so, she is not just complicating the riddle, she is creating an implicit comparison between this train and all the creatures of the natural world that actually do feed themselves, crawl, complain. By describing it in the language of the natural world, she creates a striking juxtaposition between it and that world.
And although the speaker says she likes to watch it do all of these things, her tone and diction belie this statement. She does not seem to like its power, how it can “lap the Miles” and “lick the Valleys up,” and take but one “prodigious step” around, not just one mountain, but “a Pile of Mountains.” Her description of it as “supercilious” is certainly explicitly negative, and she does not seem to like the way it can carve space out “To fit its Ribs,” transforming the natural world for its self-centered needs.
Its sounds are described in the most negative sense—“horrid” “hooting” and “complaining”—and the description of its downhill speed as chasing “itself down Hill” casts significant doubt on its intelligence. Indeed, this creature even seems to be impinging on her own role as poet, as its complaints are in “horrid, hooting stanza,” thus in poetic form, although clearly not well done as the alliterated adjectives emphasize. So while the speaker claims to like watching this spectacle, she certainly does not like the creature itself, whether she likes the process of observing it or not.
The train’s explicitly negative characteristics are all framed to be applicable to real creatures, too—in fact, much more so than machines, which can’t be “supercilious” or “complaining”—however, they are combined with the train’s great power—it is “omnipotent,” which makes them all the more irritating and disturbing. It is a blight on the natural world, taking on its more negative characteristics and combining them with too much power. Indeed, the fact that she never names the train explicitly seems to reflect that it is not meant for this world and doesn’t fit in at all.