Not blaming you at all since I assume you’re also pretty young, but I’m so surprised people didn’t step in to help those kids. A simple “oh my gosh hi guys! I haven’t seen you in so long how is your mom?” And then ushering them away or helping them move train cars is something that seems east enough to do. Sure the kids might be confused at first but hopefully they would pick up on the fact that the person was helping them? Idk maybe that’s not the right thing to do but I would feel compelled to intervene in some way as an adult.