Mostly I like your photos. Being a thorn instead of a rose, here is a list of what I think could be better.
It seems to have been taken from your full standing height. Train tracks are cliche and with little fall colour and straight tracks, this is not a winner. Taking the same photo from much nearer the ground may improve it, or not. A really, really long lens may improve it, or not. Different light might improve it, or not. Someone once said if you want interesting photos, you have to stand in front of interesting things.
That’s a serious arch! Too bad about the sky. Sometimes the giant softbox leaves you with flat looking photos.
Crop this just above the lowest building with a blue roof on the left. It will get rid of a lot of scruffy junk and make it look better.
Yeah, this needs a different perspective, and/or a different day or change of light. See that stick, sticking into the photo at the left side about the top thirds line? Watch your edges.
Makes me cross eyed! A longer exposure, perhaps? Two or three times as long as you used to smooth out the flow. A little brighter on the log, maybe. Try cropping off the top, just below the shelf (below the left most two leaves).
If this is a raw file, try dropping the exposure of the bright parts slightly and adding some fill light to the shadows. It’s nice as it is, some editing might improve it.
I think it was Scott Kelby that said you should only have flowers in your portfolio if you shoot for a florist. The rational was that flowers are provided beautiful by nature, so you really have to nail the shot and nothing less than perfection will do. “Vivid Red” and “Love me tender” are past their prime!
I’ll start by saying you could probably count the B&W photos I like on your fingers and toes. I’m not much of a fan. Sometimes B&W is a way of fixing sins. I have taken a couple of colour photos that look like they were done in B&W. Your high tension electrical towers have strong graphic elements so that shot should be a good candidate for B&W. Unfortunately that shot is quite muddy! If it were a pencil drawing I would say it was smudged. You could probably put a white layer behind it and mask it to clean it up. Or, edit it again if that is not the way it came out of the camera.
The US side of Niagara falls would probably look better in colour. It definitely would if you had blue sky that day. Colour helps the walkways stand out from the rocks and separates the falls and sky. B&W makes it look drab. Both tree shots are too busy. Does either one have a focal point?
http://www.picturedrox.com/Black–White/i-FHBvx77/A looks like old, bent, cedar beside rapids — or is it just uneven ground with some snow? I bet it looks better in colour. If not, discard it.
I’m not seeing the point to either shot in Alternate-Reality.
I think you have a good understanding of how photography works and can get the results you desire.