Well, its already been said that there are blown out parts in these. In this case, if you have no other choice than to shoot at this time of day, I would narrow the aperture to at least 9, and adjust the shutter speed accordingly so that they arent so bright.
The blowout is quite severe in #2 and #3, but I think #1 and #4 can be saved if you run a defog on them, so that they are not so hazy. Just use USM 40, 60, 1 and see what you get.
Also, its a good idea to watch out for hair in the eyes, as in #4.
If its such a crime to take pictures on railroad property, then why do I see so many model shoots done on railroad tracks?
On the upside, your model is very lovely, and I hope you do more shoots with her.