Paint the rail and the track. Until I reread your post I thought it was N scale because the track stood out so much.
For "better" pictures, check your scenes for anachronisms. NOTE: I am not saying he can't run equipment from different eras together, just that the pictures are more compelling when they are consistent.
Some of the weathering is a little heavy, but its not over the top, you might want to make it consistent. A little weathering on everything looks better than a lot of weathering on just a few things.
Practice your rock making skills Your grassy fields turned out really nice, as did the area around the stock pens. Put that same level of detail and care into your rocky areas and hills and it will be stunning.
Other than that the pictures and modeling was good, a lot of very good scenes. Good job.
Dave H.