How does Martin Espada use imagery in We Live by What We See at Night?

In Lines 7-10, Espada uses figurative language to extend the scene into the past four generations: the poet, his father and his father's grandfather. Perhaps the poet is emphasizing the deep sense of tradition, son following father in a continuing line from the past, crossing the same bridges. Note, too, this is the second time the poet mentions dreaming, though this time it is "interrupted," suggesting his father's difficulty sleeping.