There are no railworks pluggins for blender as such, that I know of. There are two RW exporters that I know of, and I have been using this one:
http://members.uktrainsim.com/filelib-directory.php?form_hide=on&form_country=15&form_sim=14&form_path=ty=10,cls=2838 It comes with a pdf help file, which is kind of daunting, because it was written by someone much smarter than most of us. You just have to fool around with it; trial and error. Mostly error, but it does work. I have managed to export some fairly simple models, with night textures. I haven't figured out the LODs and grouping quite yet, but I am
close. The problem that you are going to run in to is this; there are a few tuts out there (on this forum) that show how to export with blender 2.4x. Blender is now up to 2.69, and the interface is different. I really like working in blender now, but translating the work to TS is a pain in the arss! Mainly because you're blazing your own trail and watching reams of blender tutorials on youtube. Oh, that's just me... sorry. I will write a tutorial when I feel confident enough, but for now, I'm in the wind. And dang, now you have to interface with the new brownprint, er, blueprint editor which is like sticking straws into a piece of Styrofoam.
Down another rabbit hole we go....