The Rose
The rose, which symbolizes beauty, is personified as a woman. She could be naked or wearing a dress. If the rose is naked, she is concealing nothing. Her beauty is intrinsic to her being. If she is wearing a dress, the implication is that she is hiding something under the surface—that reality is concealed. This could also be a question about human perception. What do we see when we see a rose? Do we see the real rose "itself," or only the appearance of the rose? Is the beauty of the rose intrinsic to it, or something that we humans create?
Trees
The trees in this poem "conceal the splendor of their roots," which is a metaphor which can be read several ways: politically, spiritually, and socially.
The Thieving Automobile
It’s a criminal automobile, a thief—but with regrets. Because the speaker has implied sympathy for the car, we are made to wonder if the car is doing something against its will. It may be a victim of human desire. Perhaps it regrets stealing resources from the earth.
A train
The train is standing in the rain. In asking a rhetorical question wondering if there is anything sadder, the speaker makes us think about whether the train itself is sad, or whether it is a sad sight. If the train is sad because it is paralyzed, do we find this as sad as a paralyzed human? Why not?