One of the most common configurations in model railroading is the circle or oval. The neatest thing about Trainz is that this type of track layout is allowed. You can set up a simple oval, put a locomotive on it and presto! You're running a train already!
IIRC, the "other" simulator will not allow this type of simple track setup (at least not without severe fiddling). Being able to jump into Trainz route creation so easily is excellent! You old time route creators probably take this for granted by now, but as a still relative newbie, I find this amazing.
Andrew

Andrew