SAN FRANCISCO » About dinosaurs, the old masters, they were never wrong, to paraphrase W.H. Auden if he were writing a poem about the endless fascination kids have with prehistoric beasts. That fascination is part of the reason "Dinosaur Train" is popular among the youngest members of the PBS audience and why the show’s fans will enjoy the new special "Dinosaur Train: Submarine Adventure," airing Tuesday.

"Dinosaur Train," which premiered in 2009, "stars" Buddy, a curious young Tyrannosaurus Rex whose egg somehow winds up in a nest of Pteranodons (technically flying reptiles — not dinosaurs).

Buddy and his scaly buddies ride the Dinosaur Train around the prehistoric jungles, volcanoes and other settings, learning about species. At the end of each show, a live-action segment with paleontologist Scott D. Sampson helps young viewers learn about the species they have just met with big, unpronounceable names.

"Submarine Adventure" follows the format of the show, but the submarine, of course, gives the dinosaurs a chance to learn about undersea life, including Otto the Ophtalmosaurus — whose speaking voice is disconcertingly reminiscent of Arnold Schwarzenegger’s — Shoshana Shonisaurus and Maisie Mosasaurus. By tapping into childhood fascination with dinosaurs, the series and the special teach kids not only about various prehistoric species, but, in a more subtle way, about the diversity of life in the world. Buddy is a welcome member of a blended family.