@Thara Good points. In my opinion, the 60th Anniversary Thomas is the definitely the hardest to find for two reasons: (a) it is very tough to spot in large lots because of how similar it is to a regular Thomas and (b) most people would think it’s just another Thomas and treat it like any other toy. It’s funny how compared to its age and number produced it has appeared very few times and is the most mysterious, even more so than the Gold Thomas (even Muddy doesn’t have one!)
plarail for life