"train people"

I received the following note from a non-subscriber. Any thoughts or sources?  "There was a place along the levee between Henderson and Catahoula where, between around 1950 and 1960, very poor people lived in train cars, free box cars gifted by the government. My memory of them comes from spending summers with my grandparents, Wade O. Martin Sr., and Alice Mills Martin, on their rice farm in Catahoula, situated along the borrow pit canal. However, I haven’t been able to find any evidence of their existence in print."