For those of you without children in the 3-7 age group, Dinosaur Train is a PBS series revolving around Buddy, a Tyrannosaurus Rex, and his adoptive Pteranodon family. They live in the late Cretaceous (probably the Santonian Stage) on Western Interior Sea. Then there is the train--operated by Troodons--which can traverse various "Time Tunnels" to visit other ages of the Triassic, Jurassic, and Cretaceous epochs.
I've watched the entirety of Season One with my daughter, and a few smatterings of Season Two. I'm struck by how much world building clearly went into this series. Despite the focus on adorable preschool-aged T. Rex buddy and his loyal and compassionate sister Tiny, the world they live in a wholly a construct of time-travelling Troodons. They are the masters of the universe.
The Troodons run the train that links all the Mesozoic together. They have the only stop that has the word "town" in its name, everybody else is an "acre" or "terrace" or "station." They may have the only city in this world, and from the looks of things, only Troodons are allowed in it. In all the episodes I've seen, we've never seen Troodon Town proper.
They're civilized. They're the only one to wear clothes, usually a jacket, sometimes a hat or jewelry, but none of the other dinosaurs come anywhere close. Junior Conductors wear a hat, but only while on the train. This indicates that Troodon society has access to textiles and manufacturing.
They are benevolent. They never charge for a ride on the train, but insist on every passenger having a ticket. They're concerned that not every kind of dinosaur can ride the train. For instance, Arnie Argentinasaurus can't ride the train because he's too big--that is until Tiny and Buddy recommend converting a flat car to transporting him and his even larger dad. After a brief engineering meeting, they reprovision the flatcar. They've even gone so far as to create aqua cars to accomodate their sea-dwelling passengers.
They are educators. Mr. Conductor cannot help but educate his passengers on the various extant dinosaur species and actively encourages cross-species cultural exchanges. They even host concerts with King Crylosaurus as the main attraction (a popular singer across the Mesozoic).
More importantly, they have taught every sentient or near-sentient species in the Mesozoic how to speak the same language (and based on the puns, it's English, which opens up a whole new can of nemotodes). Tiny Pteranodon even claims to be able to read the brochures at the train station, which if true means that they've been active in universal literacy despite the obvious lack of libraries, books, and magazines among non-Troodons.
They are social engineers. Though it's never explicitly stated, they are probably the ones who put Buddy's egg in the Pteranodon nest. Tyrannasaurus lived during the late Cretaceous, much later than when pteranodons ruled the skies. The only species with the power to transport eggs across eras and in cross-species harmony are the Troodons. No doubt they felt that Buddy would be better bred in an earlier time with a larger, less meat-centric, up-bringing. Or they were just fucking with their power.
The troodons, despite a round house of the Dinosaur Train existing in the early Triassic (which a pump car to get to the sticks), and the second at Troodon Town near the Cretaceous-Paleogene event horizon have visited the late Victorian era, if the makes of their trains, their clothing, and their decor are any indication. Thus, their time tunnels aren't limited to the Mesozoic.
Lastly, and most brilliantly, each station in stage exists in a fixed timeline along a continuum. What I mean is, if I live in Pteranodon Terrace, but I visit the late Cretaceous on the Dinosaur train (say T. Rex Station), then the same time passes back home as it does in the ostensible (and poorly named) future. So every major stage of the Mesozoic is linked as though they exist in the same timeline. I'm floored. This is awesome.
Why would the troodons go to so much trouble to uplift nearly every major species of the Mesozoic?--even frogs and turtles and hermit crabs are considered worthy of linguistic education. Maybe they truly are benevolent and want to usher in a millions year rule of Dinosaurs as the undisputed masters of Earth--which if you do the math of years between stations, that's how long their nascent society should last without stepping into the next era. But it seems based on their train technology that's taken right from the 20th century our time, they know what's in store for the the reign of dinosaurs, and thus are they looking for an escape from the Cretaceous-Paleogene extinction, and trying to engineer a species and a society to side-step the inevitable?
Or maybe I watch too much Dinosaur Train.