#1 is really dark, and it looks like some leaves got blurred in the foreground. You might try raising the levels on the lower half, and saturating the sky to bring out more of the blue.
#2 is interesting with the tracks. Another perspective you could try is shooting from the tracks and looking up at the bridge, with a focus on tracks closest to you.
#3 has nice color. Could be a bit brighter though.
#4 is cool. But it would be nice to see a ripple where most of the flag is showing. I know its hard to get it to ripple just the way you want it though.
#5 is good. Would like to see you zoom way in for an ever nicer macro shot with more detail.