Answer:
"In horrid, hooting stanza,"
Step-by-step explanation:
The poem speaks of the train as if it were a horse. It speaks of its movement, the landscapes it encounters and when it stops. The poem can describe the train in a very light, poetic and melodious way, we can see the comparison of the train with the quiet and free riding of the horses. In a specific line from the poem, the author uses imagery to describe the sound of the train, that line is "In horrid, hooting stanza".
As you may already know, imagery is a language figure that seeks to influence the reader's senses (smell, hearing etc) through words.