To the OP and all others concerned:
TS2010 runs great on my 3.2Ghz dual-core, 4Gb, 8400GS, Windows XP-32bit gaming rig with all the sliders maxed out. It runs even better on XP-64, which I have dual-booting with that XP-32bit, since XP-64 can utilize memory better than 32-bit operating systems. The kicker is, Trainz ran pretty well on my minimum-spec 2.2Ghz (E2200), 1Gb memory system sitting next to my current one, now serving as an email/internet/putzing around machine, albeit I didn't max out anti-aliasing. The moral of the story is, Trainz can run well on a really, really low-end system and if there's an issue, you need to tweak your machine.
Two quick tips: Switching to DirectX from OpenGL (or vice-versa) often helps some people. There's a program called GameBooster which some here recommend to shut down unnecessary background processes.