Neat finds, Richard. Looks like a surprising amount of tonnage behind the RS-1 for 875/876-I am not familiar with the orientation so I don’t know which way it is pointing. The second photo appears to have one of the cupola-topped combines bringing up the rear.
That first picture more than likely shows train #876 northbound at the depot. It would depart daily at 11:25 am except Sunday until 1959.
I forgot to add this photo in the original post but here is a view of the station in Poplar Bluff looking northbound sometime in the 1950’s.