The passengers on the train are awakened by a child's cries. They complain to the child's father. He tells them that the child's mother is dead "in the baggage coach ahead." Upon learning this, the passengers turn helpful
Various "real" stories have been claimed as the inspiration of this ballad -- e.g. Randolph reported it to be based on the real-life story of Dr. James B. Watson and family. Watson's daughter Nellie was born in 1867, and the girl's mother died in 1869. Watson was taking his wife's body back to her home in Pennsylvania when the events described took place.
On the other hand, Spaeth notes that Charles K. Harris wrote a song "Is Life Worth Living," with almost the same plot, some years before Davis produced "Baggage Coach." Whether based on an actual incident or not, the idea amply met the nineteenth century demand for tearjerkers.
Cohen's notes on the song include four other dead-body-on-the-train songs, and list other people on whose story the song might have been based. Adding it all up, it seems likely that there was *something* in existence before Davis worked on ths song, though the Davis text does seem to have become canonical. - RBW