Two from my world that I know of. Where they were one version. That version went away and another took it's place.
No. Wait. . .Three from my world, I think.
One girl died another version replaced her and now the new version is gone too. Hang on. Let me count. . .
Several from Lily and Jaime's world have been disappearing and then showing back up as replacements, I think. Lily's family in particular it looks like.
We don't know how the train chooses or why it cycles through people. Most of us are just assuming it's an asshole.