Ella also sang a version of "Dry Bones" to my mother. I think you've nailed where the last three verses of "Gospel Train" came from. When our family friend Wendy was transcribing Ella's songs, she was doing so in the early 1940's as remembered by the Zorach family. So, some folk processing may have taken place in the renditions recorded. Ella died in the mid 1930's.

Charley Noble