The phrase "dust to dust" in "Yesterday's Train" comes from the Bible, specifically from either Genesis 3:19 ("'you are dust, and to dust you shall return'") or Ecclesiastes 3:20 ("All are from the dust, and to dust all return").
In the line "Yesterday's train is rollin'," "rollin'" is sung with a melisma (G F# E), giving a sense of this movement.
