Looking at their explanation, this may favor very small locations. As a test, I typed in “wombat” and the top of the list is someplace called Allison Park, USA, which I’ve never even heard of. This could happen if, for some reason, every kid in the 5th grade at Allison Park Elementary School had to do a report on wombats.
For the model railroad example, having a place as large as Pittsburgh at the top says that the statistics are probably valid.
It’s interesting that each year shows a gradual buildup of searches starting about in October, peaking right about December 25th, and then rapidly falling off again. And, as many people have commented, the summer in the Northern Hemisphere seems to be a slack time.
Not sure how they are grouping the cities though. Last time I did a Google search, it didn’t ask me where I was from. I suspect it is grouping from the region where the ISP is located, that is, since Pittsburgh would have most of the ISP servers for western PA and eastern OH, that may be why they get listed number one.