Based on "The Valley Was Still" by Manly Wade Wellman, first published in the August 1939 issue of Weird Tales.
Railroad rail traces are obvious under the locomotive. The traces continue back under the wagon the soldiers are loading. In mid-19th century rural America any train tracks that ran through the center of a town, the town having sprung up along the tracks, would have the rails almost buried and the sleepers (ties) not visible at all. Rail speeds through towns was very slow and any fully surfaced railroad rails would be a major disruption for wagon and carriage traffic. This is historically correct.
The flag portrayed is historically correct, with four rows of seven stars and the fifth row, the middle row, having six. The row with six stars, the middle row, would either be missing the center star or have them centered on the blue field.
Originally aired 100 years after the beginning of the American Civil War (1861).
The only half hour episode to be rerun during season 4.