Got it: West Tennessee Railroad, Jackson, TN (35.601442, -88.800486). I narrowed it down using the red B23-7.
Been wondering for a bit now, but does the chosen location need to be currently active? Or can it be long gone? That is, remains of what once was. Have an idea or two, based on that!
As long as it is still on the map and still has tracks close to it, I don't want to be combing empty fields in Iowa...