Besides, if we wanted realism to the extreme, we'd get Train Sim by Dovetail (which I own because I like both simulators) and MSTS. Trainz has realism too, but it's more loose with it, and I prefer that for TRS, as opposed to TS or MSTS.
The stuff out of Train Sim is extreme, it's perfect photorealism.
The reason I fell in love with Trainz is that feel of looking at a real model railway or even something you threw together in your basement one day with some extra wood and a few old model trains laying in a box.
I must say my graphics card handles this game much nicer too on max settings.