Who knows?
I've just been reading the lyrics again. Maybe it's only partly about Katrina (the rain, "a night with no tomorrow").
The story of the child is confusing... the child could be the storyteller (not MK!) himself, thinking about his own past, or the storyteller is the father of the child, or the child could be the newborn baby of a complete stranger that he finds in the railcar in the middle of the night.
I'm not sure about the time, either. The story may be set in the past, as there are always floods and hurricanes in the Delta, like the one in 1927.
The idea is, anyway, that it might be about some famous old blues musician, born in a forgotten railcar in the Delta, maybe a hundred or more years ago. Has anyone got an idea who that might be?
Or maybe I'm on the wrong track ;-)