I I like to see it lap the Miles —
And lick the Valleys up —
And stop to feed itself at Tanks —
And then — prodigious step
Around a Pile of Mountains —
And supercilious peer
In Shanties — by the sides of Roads —
And then a Quarry pare
To fit its sides
And crawl between
Complaining all the while
In horrid — hooting stanza —
Then chase itself down Hill —
And neigh like Boanerges —
Then — prompter than a Star
Stop — docile and omnipotent
At its own stable door —
F382 (1862) J585
Helen Vendler includes this poem in her wonderful collection, Dickinson: Selected Poems and Commentaries. I really have not much to add to her commentary, but I can summarize a few of her points. Vendler notes that Dickinson's father was a backer of the railroad whose eventual station was located close to the Dickinson house. Dickinson would have been able to hear its "horrid – hooting stanza" as she wrote.
Vendler has some fun listing the different animals the train is seemingly like: it laps and licks as a cat would; it neighs like a horse and also like a horse has a stable. It can also peer in shanties (superciliously!), pare down quarry walls and then crawl between them, and it has a "prodigious step" like a giant. Most interestingly, it is both "docile" and "omnipotent".
She makes other points about the poem, but she doesn't account, I don't think, for its charm. At least it has always charmed me! I, too, like to see the train lap the miles – but I like it better in this poem than in real life, for Dickinson has created a cartoon train. The entire poem unfolds as if it were an old Disney black and white. I follow each line and have no trouble visualizing the action. Frankly, it never occurred to me to question the mixed metaphors. Each segment of the poem seems another stage in a journey and I am along for the ride.
Part of the energy comes from the use of "and". It goes here and it does this and that, and then finally it is home. It's a headlong adventure. The language is also fun. Lapping and licking the miles and valleys is fun, as is the train taking a break at a tank like a thirsty horse before it's off again. (Presumably imbibing the miles and valleys didn't quench its thirst.) The prodigious step is another fun phrase and image as is the Pile of Mountains. I see the train as a giant inch worm raising itself up and coming down on the other side of the hill.
It's not uncommon to see or imagine seeing people looking out the window of a passenger train at the yards along the other side of the track . There is something supercilious about it, but Dickinson has the train itself become like a snobbish passenger.
Perhaps the most fun image is that of the mighty train carving its track through a rock quarry, and then having to crawl through, "Complaining all the while". Those hooting stanzas were probably painfully familiar to Dickinson. In Vendler's final paragraph she writes, "The train is Dickinson's self-parody, a bad poet."
I must confess that I always thought Boanerges was the name of some famous war horse. Vendler corrects me: in Aramaic it means "Sons of Thunder" and Jesus called James and John, two disciples, by this name. The Dickinson Lexicon lists an additional meaning as a "loud orator" or "vociferous preacher". Google helped me find it used in an 1862 manuscript about evangelists. In referring to a Mr. Bell, author Madison Evans writes, "He has a strong, deep voice, and his loud, rapid, and sometimes vociferous utterance has won for him the sobriquet, Boanerges. … He closes every discourse with a powerful exhortation, in which his voice sometimes rises to the highest pitch" (from "biographical sketches of the pioneer preachers of Indiana"). I wonder if this frontier Boanerges also ended up at his own stable door "docile and omnipotent". That's another fun image.