Not so fast...
I chased the FPS gold ring for years. ( Trainz is the only "game" I've ever run) I went from an old Dell made in 1999 running W2K, to a whitebox that I built several years ago with an ASUS MB, AMD 2+gig processor, 2GB memory, and several different video cards from ATI and Nvidia.
I now run Trainz '04,'06 & '09 on a 6 year old HP laptop with an antique Nvidia Geforce GO 5600 onboard video card with 5 year old drivers and all versions of Trainz run just fine. ( it does have a 2.8ghz P4 and 2gb memory)
BTW, I run "default" settings as far a sliders go...which is usually in the middle.