It's eight in the evening, you've had your buddies/neighbours/girlfriend/stock broker over for dinner, for lack of any topic of conversation, you ask if they want to see your model railroad.....]
Wait a minute. You mean a model railroad can actually help you find a girlfriend? Wow, I gotta be more serious about that.
Now if I had a girlfriend, I'll bet she'd be much more impressed with the former than the latter.
Oh. Okay, never mind then.
Seriously though. I would have to fall into the camp who believes that the two are really not the same. Not entirely at least. I'm active in both model/garden railroading and (now that I've upgraded) virtual railroading. Speaking for myself, my goals for both activities are different.
Down in the basement where my small On30 pike is set up, I'm focusing on modeling one tiny section of an admittedly tiny line. While I can do that in Trainz, this form lends it's self a bit better in my view as the minimum dimensions for a layout in Trainz is 720mx720m. And I always feel obliged to use that space. But that's going off track and really not my argument. Right, focus. My goal with On30 is tactile. I want to be able to pick up that Porter and disappear in the workshop for four hours on a rainy Sunday afternoon and emerge that much later with only a very, very nice 1:48 scale red toolbox on the footplate to show for it. That's not much of an exaggeration either, sadly.
With Trainz, my goal is not to simulate real world railroading as accurately as possible (Model Railroader once ran an editorial on the many reasons why such a thing would actually be quite boring, such as sitting at a signal, waiting for long periods of time), but to achieve a happy medium. I want to be able to sit down for an hour and transverse a larger distance than I can ever possibly hope to recreate in the basement.
And garden railroading? See my argument for On30. The one difference is what I do for four hours on bright and sunny Sunday afternoons: sit under the tree with my favorite alcoholic beverage and watch my train go around.
Oh yeah and the neighborhood kids seem to like it to.