I didnt really play with the saturation, i was going to do a HDR of that scenery but when i saw the pictures i realised that the underexposed one looked fine cause the railroads were sort of highlighted.
I, too, think it's a bit too dark. But I also don't like the crop. I think there's too much sky and foreground. IMHO this would be better in a landscape orientation with the rails going off the bottom of the photo and the top cropped just above the top of the right tree.
I quite like it; the dark areas around the foreground near edges are a bit heavy and if it weren't for the reflection on the rails, it would be a very oppressive image, but with the sunset, the reflection and the caution signal, I think it all ties together well.