WARNING: The following article contains spoilers for Infinity Train Season 4, now streaming on HBO Max.
Infinity Train sadly will not be running forever, but the fourth and final season (for now, at least) continues to demonstrate the concept's infinite potential. The six train cars showcased within Book Four are among the series' most interesting, with imaginative concepts, beautiful design and intense challenges. Though Book Four is a relatively lighter story than previous ones (no traumatizing death scenes this time), the cars Ryan and Min-Gi travel through also have their fair share of darkness, both of the morbidly humorous and existentially horrifying variety.
But which of the Infinity Train Book 4 train cars is the best one? We've ranked all six of them, from the moderately fun to the downright mindblowing.
The Old West Car
The Old West Car is rather self-explanatory: it's an Old West frontier town, with the whimsical Infinity Train twist of being inhabited by giant insects. Even as the lowest-ranking car on this list, it's still a pretty fun one, just not quite as special as the other ones in Book 4. Highlights include a caterpillar sheriff who metamorphosizes into a butterfly judge, a bug zapper used to execute people and this season's appearance from Samantha the Cat in the saloon.
The Art Gallery Car
The Art Gallery Car is another rather self-explanatory car: it houses an art gallery, with the exit door hidden as a puzzle within one of the works of art. This is the quietest of the cars in Book 4, but it's a nice showcase for Infinity Train's impressive background design. Its most striking feature, however, is that it's home to the series' most terrifying monster: a chilling shadowy beast made entirely of hands known as "The Docent" that preys on people's hopelessness. The exit puzzle also only allows one individual to exit at a time, which seriously tests Ryan's commitment to working things out with Min-Gi.
The Astro Cue/Party Car
This is one of two cars to be split into two settings over two episodes. In the Astro Cue, astronauts wait in lines upon lines, hoping to be let into a party by a bouncer who crushes the rejected into cubes. The lines go on for so long that many of those in line have long since died. The challenge of getting in proves to be a major learning opportunity for Min-Gi, who realizes he can't simply wait around following the rules and that he shouldn't be so dismissive of Ryan's creative problem-solving. The solution that gets them into the party and ultimately out of the car involves posing as the party's "entertainment" and finally performing together again as Chicken Choice Judy.
The Pig Baby Car
Simultaneously one of the funniest and most frightening cars this season, the Pig Baby Car is home to a giant pig baby voiced by J.K. Simmons and his cow creamer guardian. The task at hand for Ryan and Min-Gi in this car is to cook a meal the baby will enjoy, a challenge when the only cookbook not accidentally destroyed by Kez is all disgusting post-war American recipes. The dark twist is that even after making a perfect treat for the baby, the cow creamer demands more food until the pig baby dies, at which point she plans to turn the passengers into the new pig baby. The only escape is inside the pig baby's mouth.
The Mega-Maze/Castle Car
The second two-part car of Infinity Train Book 4 is the final car on Ryan and Min-Gi's journey. The maze, where they're chased by all the previous cars' denizens who were wronged by Kez, surrounds the main event: a sentient castle named Morgan. Similar to the cow creamer in the Pig Baby Car, Morgan wants the passengers it hosts to stay with them forever. Kez used to live inside Morgan along with another passenger named Jeremy; she left when she upset Morgan by helping Jeremy deal with the death of his parents and find his exit from the train. This story showcases the difficulties of passenger-denizen friendships, as well as how Kez is essentially a well-meaning individual who nonetheless completely fails at basic communication.
The Iceberg Car
Infinity Train Book 4's most creative train car happens to be the first one Ryan and Min-Gi land in. The official name of "The Iceberg Car" is something of a misnomer; while the two passengers arrive upon an iceberg, that's only because they've arrived in the midst of an ice age. A time-travel device, initially attached to a vending machine before Kez broke it, controls which era in history the car and its denizens exist in... though no matter their evolutionary state, the denizens always want to go on a ski trip. From prehistoric times to alien futures, this car makes for the most exciting possible introduction to the train.