Nice photo, good subject, well composed. The background seems a bit washed out and would benefit from a bit of work with levels, curves and contrast. I like the river. It gives perspective and interest. It may not have been possible but if the observer could have been a bit higher, the river could have added additional interest.
A bit too much going on in this image with the cows and stream and trees up at top. It'd be nice if you could have gotten in tighter on the engine and the thick black smoke and really filled the frame with that. Great subject either way. :)