One of the less obvious errors in Dinosaur Train, as in practically any other Pop Culture depiction of dinosaurs, is the way they so casually mix dinosaurs from different geographical areas and from different eras together. It’s like Zootopia, but without the notion of different habitats. And with mastodons and saber-toothed tigers thrown in.
Apatosaurs and Stegosaurs and Camarasaurs lived in the Jurassic (200 - 145 Million years ago), while T. rex and Triceratops lived in the Creataceous (145-75 Million Years ago). (At least T. rex and pterosaurs were contemporary, so Buddy and his family could temporally co-exist.) Putting different groups of dinos together like that is equivalent to writing a play with Joan of Arc interacting with Ben Franklin, just because they lived long ago.
(I used to keep straight who lived when by recalling which rooms the fossils were mounted in at the American Museum of Natural History)