These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Iconic Character, Forgotten Title: Commonly called "Thomas the Tank Engine" after the show became popular. It doesn't help the merchandising between the two products sometimes interchanges and some versions of the original novels are even released officially with the Thomas moniker.
Nightmare Fuel: Many of the books about scrapping, even Edward the Blue Engine, seem to traumatize steam lovers.
Villain Decay / Time Marches On: In the 1960s, books like Stepney the Bluebell Engine and Enterprising Engines dealt with the subject of steam power being scrapped. In James and the Diesel Engines, published in 1984, a visiting diesel notes that on BR, "steam engines are kept in their proper places, and aren't allowed out on the mainline without special permission." (referring to the red tape surrounding steam-hauled railtours.)