What PC best for Rail Simulator?

[blehmann]

I am thinking about getting a new PC to improve on the ASUS laptop on which I'm running RS at the moment. My main interests in life are RS and from time to time a bit of Trainz. (I'm not much of a gamer in other respects.) What's at the moment a good specification in terms of processor, graphics card (Nvidia or Radeon?) and memory? I don't mind splashing out a bit more with view towards the future.

I would appreciate any advice.

Thanks

Burghard :)