I actually am not saying that we know this either way. I just don’t believe that the fairytale world is under Storybrooke. I have seen no evidence for that to be the case. And it really seemed like the smoke was destroying fairytale land as it swept over the Enchanted forest and the room that Snow, Charming, and the queen were in when the curse happened seemed to be tearing apart.
And the Toll bridge is the place that Charming went when he woke up from his coma without memories because he was looking for Snow. Also the mines did not seem to be the same. There was medal structure as well as a hatch and a shoot and i don’t remember there being diamonds in the walls in the real world. Also the queens heart room was different in the real world then the one in the fairytale world. I just don’t see any evidence that fairytale land is under Storybrooke. And honestly i don’t see a reason as to why they would do that.