I choose numbers three and five.
Number three displays the beautiful panorama in which the railroad has been a part of for so long. The contrast of 463's clean smokebox stands out against the oncoming passenger train while the cattle and people in the foreground connect with the human element of why the railroad was there in the first place.
Number five does an excellent job of making you feel as if you've just stood trackside and watched a doubleheaded freight pass. You can almost feel the ground shaking and hear the exhaust bark from the locomotives.