I have it running fine on my laptop; Gateway 9300 XL; win 98 SE, 128 MB; ATI mobility rage pro/8Meg video. A bit jerky at high detail, but with a 500 MHz processor, what do you expect?
But I have trouble coupling the train together! It worked sometimes in the tutorial, but last night I gave up after 10 minutes. I tried going slow, fast, but all I did was bounce off the cars. ANd I had left them so I could leave off the car I was supposed to leave off.
Other than that, it is fun; had a great time with the Flying Scotsman steam loco.