Rarest Plarail/Tomy Trains

There were Plarail sets that replicated the use of railway tokens? Not even model railway companies offer such things, so it really surprises me to see them in toy sets (let alone one with a Thomas themed variant). I don't see an average child being likely to know what they're supposed to be, even if they've read Stepney the "Bluebell" Engine and understood the line "He slowed to exchange tablets". I can only wonder what other such unexpected real railway features were rendered in Plarail.

Speaking of a "mail hook": Check out this neat custom mechanism for un/loading TrackMaster Mail Coaches while they're in motion. Genius compared to the "loader" accessories in official sets.