I love the idea!
How about a special brick pack to go with it? If someone does make a special brick pack, make it so that the train can't go off of the bricks unless you stop making the bricks and the train goes of and that will make the train crash. They should be bricks "station bricks" that make the train go slower and then stop at the station. The train should be completely controlled by bricks and events. Like "onactivate>namedbrick>setrainleavestation" or something like that.
Off topic: You do know that sketchup is used by architects to design buildings, right?