Believe it or not, I am a fan of train simulators. No, that's not weird. Trains are fun. And Trainz Driver, the mobile version of Trainz Simulator, manages to be a fun experience while not quite looking as good as we want our train simulators to look.
If you've never driven a train before, know that it's not that complicated. You have a throttle, and you have your brakes. Well, you have a few different kinds of brakes. The point is though, that you don't have to be a genius to figure it out. But if you want to be good at driving a train, you have to have patience, as impatience will have you rolling through the countryside at a high speed and risking derailment.
You have to pay close attention, but you do have time to enjoy the scenery, and that's what Trainz Driver lacks. I like my train simulators to make me feel like I'm actually rumbling through the world, but Trainz Driver is too primitive, graphically, to provide that feeling. You will see plenty of texture pop-in as the game loads the areas you're traveling through while you play, and that's a big distraction.
What I can say is that Trainz Driver, at $2.99 is a good place to start if you think you might want to play a train game. It's much better to risk that smaller amount to see if you like this type of thing than to drop $20 on a PC game first. Trainz Driver is an authentic enough experience, driving-wise, that I can say does work as an entry-level train game. if you enjoy Trainz Driver, though, you'll probably want to move on to a higher powered experience rather than obsess over this.