I like to see it lap the Miles —And lick the Valleys up — (1-2)
While it's cool to think about the train gobbling up the hills and valleys as it goes, it's also kind of creepy and menacing. This image of ravenous eating doesn't bode well for the natural landscape.
[…] prodigious step
Around a Pile of Mountains — 5
This image dwarfs both man and nature in relation to the train. The word "pile" trivializes the mountains, and makes us feel our own smallness and weakness; if we're already teeny tiny and insignificant next to a mountain, how can we possibly compare with the power and majesty of the train?
And then a Quarry pare
To fit its Ribs And crawl between (8-10)
This tunneling action of the train seems to emphasize the newfound, technologically-assisted might of man; where rock might once have stopped us, we can now pass easily.