To me, this is a song about a daughter waiting for her father or mother to come home. When it talks about her putting her ear to the ground she is listening for the sound of a train. When the dirt whispers child I'm coming home, that's the sound of the train. "Another station another mile also talks about a train."
The parent sent her a postcard from another country saying I wish you were here, but the parent just really wants to be home "holding on to simple things." The reason the child wishes for daylight is because the parent made a promise that they would be home before dawn. "a prayer for dawn but daylight isn't what she wants." "I swore that I will be there before dawn"