I don't think that the image is out of focus, just that the wrong things are in focus. In most portrait situations, it is advisable to get the eyes in focus since these are usually what you want to draw the most attention to since it makes the subject come alive. The eyes are after all "windows to the soul" and most would endeavour to photograph the "soul" of the subject and not just a flesh shell.
In the case of your photo, you have probably opted to use the centre focus point, and focused on her right arm inadvertently, rendering the eyes and face out of focus.
Composition wise, subject placement could have been far better. At the moment, the subject is not only too central to draw much attention, your composition and use of lines leads my eye to the posts on the left and right top corner. The posts on the overall seize way too much attention in this composition. The singular rail as a lead-in line does not work and seems to try too hard without actually drawing attention to the subject.
You have shown too much without actually showing anything at all, if you get my drift. It would have been far better to show more of the railway or more of the ground and less of the other, such that one element has more prominence and is more able to lend support to your chosen subject.
