What are some things that can be done to optimize frame rates for Trainz12?  I have a fairly substandard system for gaming, but right now, it seems to be running o.k.  I just want to squeeze everything out of this computer that I can.  I have only and NVidia GE Force 8500 with newest drivers.  I also changed the windows Vista graphics to bare bones for the purpose of better performance.  What else can I do to get just a few more fps in Trainz?