I agree with another reader, I would lay down or lay the camera down to the tracks, try and find a section of the track with a slight "s" curve if possible, it will make the shot a bit more dramtic. Always early morning or late evening shooting. It looks like the sky in the first and third image is blown out so maybe a ND Grad or bracket your shots next time.
I like the shot of the old barn, but it looks like a bit of a halo around part of the roof which would indicate oversharpening. I would crop out the top half of the sky, it really doesn't add to the shot and this will balance it a bit better. By itself it is not that interesting of a shot but I really think it would be a great candidate for a grungy HDR look. If you shot in RAW just reprocess two images over/underexpose and run through Photomatix.
The third image may be a bit oversaturated, of course it could just be my monitor.
The last image was exposed well but the subject is just not too interesting.
Tough love!
