Western Animation / Infinity Train

All Aboard!

"It feels like every time I find something logical about this train, it's thrown back at me and I'm stuck without answers."

— Tulip Olsen

Infinity Train is an animated Science Fiction anthology series created by Regular Show storyboard artist Owen Dennis and produced by Cartoon Network Studios. Each season revolves around events on a mysterious, seemingly endless train in the middle of a vast wasteland on which troubled individuals suddenly awaken to find themselves as reluctant passengers. Now sporting a strange glowing number on their hand, these people have no choice but to make their way through the worlds and puzzles presented by each car in order to find a way home.

• Book One follows the exploits of a teenage girl named Tulip (Ashley Johnson), who finds herself on the train after running away from home. On her journey to confront the conductor for a way off the train, she is accompanied by a Robot Buddy with a Literal Split Personality named One-One (Jeremy Crutchley and Owen Dennis) and a talking corgi named Atticus (Ernie Hudson). It ran from August 5 to August 9, 2019.
  • The Train Documentaries: A series of shorts starring One-One as they visit different cars on the train in order to create informational videos for future passengers. It aired from October 19 to November 16, 2019.
• Book Two follows MT (Ashley Johnson), Tulip's renegade Mirror Self, who is evading a pair of reflection officers (Ben Mendelsohn and Bradley Whitford) who wish to capture and execute her. After her most recent close call, she finds companionship in a new passenger, a teenage boy named Jesse (Robbie Daymond), and a mysterious deer-like entity that Jesse names Alan Dracula. It ran from January 6 to January 10, 2020.
• Book Three follows Grace (Kirby Howell-Baptiste) and Simon (Kyle McCarley), the leaders of a group of child passengers, who get separated from them after a mission gone wrong. While working to get back, they find their ideologies challenged when they encounter Hazel (Isabella Abiera), a young passenger with a broken number, and her gorilla companion Tuba (Diane Delano). It ran from August 13 to August 27, 2020.
• Book Four follows Ryan (Sekai Murashige) and Min-Gi (Johnny Young), two childhood friends whose relationship has turned sour come adulthood. After Ryan's attempt to force Min-Gi to follow him to New York in order to launch their music careers ends with them both on the train instead, the duo find themselves under the guidance of a scatterbrained hotel bell named Kez (Minty Lewis). The entire season premiered on April 15, 2021.

The original pilot was released on November 2, 2016 as a "Cartoon Network Minisode". The short received over a million views within a month and remained the most popular original short on the company's YouTube page until its eventual deletion. On March 2, 2018, a teaser site opened, revealing that a full-length series had been greenlit for a 2019 premiere. The first two seasons aired on Cartoon Network, with the show being rebranded as an HBO Max original series for its final two seasons.

During the airing of Book 3, it was revealed that the show's future was uncertain due to Cartoon Network's misgivings about the appropriateness of its themes for younger audiences. The series would end production in December 2020, with series creator Owen Dennis later confirming that Book 4 would be the final season, despite hopes that the series would be renewed for at least one more production season.

On August 19, 2022, Infinity Train and all related materials were removed from HBO Max and other streaming services, along with every Cartoon Network and HBO Max social media video and post that ever acknowledged the show's existence. In response to this, Dennis began encouraging fans to Keep Circulating the Tapes, though he also points out that the full series remains available for purchase on digital storefronts like iTunes and Amazon, reiterating his hopes that the show would be revived in the future.

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Tropes:

In General

• Aerith and Bob: The character names range from relatively normal (Nancy, Randall, Mikayla, Andy, Megan, Jesse, Amelia, Samantha) to somewhat unusual but still plausible (Tulip, Atticus, MT, Alrick) to practically made up (One-One).
• Alice Allusion: Several. Not surprising, given the premise. In fact, you could argue that the entire show is an Alice Allusion. A blink-and-you'll-miss-it moment in "The Past Car" even shows a snippet of a character's essay on Alice in Wonderland.
• All There in the Script: The names of some creatures and beings are never stated in the show, and can only be gleaned from the credits sequence unless a return appearance has that information vocalized. For example, no character refers to the soul-sucking cockroach dogs by their name of "Ghoms" until Book 3.
• Animated Tattoo: Each passenger is given a glowing tattoo with a number on it that changes based on their behavior.
• Animate Inanimate Matter: Since the Train's denizens are all Hard Light projections, they can take pretty much any form even if it's biologically impossible. The denizens of the Crystal Car are all made of crystal, including the wildlife. One recurring character, Randall, is made entirely of water; it's implied that all the water on the Train is actually him. M.T. from Book 2 is apparently made of solid stainless steel, befitting her nature as a former reflection.
• Animesque: The series has attributes of this at times, especially with the Animation Bump seen in Season 3's latter episodes, which makes the Darker and Edgier feel more noticeable.
• Another Dimension: Wherever the train is, it has soul-sucking creatures that live in the desolate wasteland surrounding it, and there's a swirling vortex in the sky that occasionally absorbs passengers who recently hit their number to zero, so they can come off the train and return home.
• Arc Hero: Each book has a different protagonist.
• Bigger on the Inside: Most of the cars are notably bigger on the inside than their already impressive external dimensions would imply, including cases where there's space behind the doors. In the pre-Book 2 videos, One-One describes each car as its own "pocket universe".
• Bilingual Bonus: A minor example: "Flecs," the term for the mirror police, is similar to "flics," a French slang term equivalent to the English "cops."
• Bilingual Animal: The series has multiple examples. Most prominently Atticus in Book 1, a dog who can speak eloquent human language, but also sings a ballad in one episode that consists entirely of howling.
• Bootstrapped Theme: While each season has its own theme music, "Running Away" is considered the de facto theme of the entire series.
• Central Theme: How to confront trauma and other psychological issues, as well as the consequences for not dealing with such properly.
• Character Development: Practically an Invoked Trope by the titular setting for passengers who wish to leave the train. The only way to leave the train is to reduce your number to 0, which can only be done by emotionally progressing into a better person.
• Civilized Animal: Several, from entire communities of corgis and turtles, to individual creatures such as The Cat and Tuba.
• Coming of Age Story: In many ways, the show acts as a Deconstruction of adventure stories where kids travel to a magical world and overcome their problems, ala Labyrinth or The Pagemaster. The train defies the Year Inside, Hour Outside and All Just a Dream tropes that usually accompany these stories, the magical and quirky companions that become loyal friends to our heroes are created solely to be avenues for their character development, regardless of the lives they live outside of that, and refusing to accept any sort of growth means you're trapped for years, maybe even decades, until you do—assuming you don't die horribly first.
• Cool Train: Once you get past the nightmarish thought that you may never leave, the train grants you the opportunity to visit an infinite number of amazing pocket universes, including one populated entirely by talking corgis.
• Dark Is Not Evil: The train itself, despite its eldritch and deadly nature, only brings people aboard as a method to help them confront their psychological issues.
• Death World: The train is surrounded by barren wastes stretching out to the horizon, which is populated by creatures like the cockroach-dog Ghoms that drain the life energy from their victims, and a vortex in the sky that occasionally shoots down beams of energy that absorb passengers. While the cockroach-dogs are definitely a health hazard, the vortex is actually a bait-and-switch, as it takes you back home. It is then revealed in "The Tape Car" that the death world may just be another part of the train.
• Digital Piracy Is Okay: Owen Dennis stated during the show's run that he has no problem with people pirating the cartoon if they have no other access to it, but also wants them to support the show afterwards once they do. After HBO Max pulled Infinity Train and numerous other programs off its service in August 2022 with no warning to even the creators of said shows, Dennis would amend his Twitter bio to state that he fully approves piracy of the show.
• Down the Rabbit Hole: Some of the trappings are different, but the gist is still that passengers enter a strange land filled with strange inhabitants and must learn about themselves before being allowed to go home.
• Eldritch Location: The train seemingly has no end, possesses creatures which defy logic, and the cars themselves have properties which don't fit their external design. The area around the train isn't much better. It's also implied on some level to be sapient with a will of its own separate from its conductor's, with Amelia being unable to recreate her old life no matter how many times she tried. The only normal thing about it is that, like all trains, it at least has an engine.
• Epiphanic Prison: The train. Its "passengers" are those who are going through some emotional problem, and the only way to escape is to gradually understand and work through it. However, it's entirely possible for even passengers who would be of the mindset to get their number down to zero to die from one of the physical hazards of the train before they have the chance to do it.
• Extremely Short Intro Sequence: A six-second intro that consists an ominous synth, followed by the show's Recurring Riff and the sound of a passing train. The train sound may or may not bleed into the start of the episode proper depending on if the characters are entering/exiting a train car or not.
• False Camera Effects: Books 3 and 4 utilize slight film grain and distortion effects to replicate the feeling of watching an older television show. A handful of episodes also make use of Rack Focus.
• Freudian Excuse Is No Excuse:
  • Tulip isn't the villain of book one, but she is a jerk sometimes. "The Cat Car" reveals that it's because her parents divorced, and she believed it was the moment they announced it that ruined her life. When Tulip actually rewatches what happens, along with other memories that had Nostalgia Filter over them, she has a Jerkass Realization: her parents were fighting for a long time, and they were as broken-up about the decision as she was. Yeah, they didn't handle it well, but they weren't intentionally trying to hurt their only daughter. She exits the tape sullen but wiser and determined to get home.
  • The Book One season finale has Tulip acknowledging that she feels sorry for Amelia, since she doesn't know what it's like to lose your husband young. Tulip also calls out Amelia for hurting Atticus and trying to Mind Rape Tulip, merely for the crime of protecting One-One from her. She says that Amelia has the capacity to change, but it has to be a choice rather than using your pain as an excuse to hurt others.
  • In Book 3, Simon becomes more and more unhinged, as his entire interpretation is brought to the ground, and Grace and him grow apart after Hazel and Tuba are introduced, that is not even to consider the fact that, to be on the train, it means he already has problems to begin with. As the season goes, Simon grows violent, manipulative, and insane as he denies all the revelations that happen. By the end of the season, he has gathered the highest number ever, even higher than Amelia, whose number went up to her neck, his covers his entire face and legs. When he confronts Grace in the season finale, she acknowledges how much pain he is in, but also says that it's not her fault, since he rejected every chance of redemption they were offered while she took it, and she doesn't owe him anything.
• Genius Loci:
  • It's somewhat implied that the train itself has a will and intention of its own. Even with Amelia usurping One-One as Conductor, the train continues to do the exact same thing it was already doing when she took over despite her being singularly focused on recreating her old life. Furthermore, no matter what Amelia does, after years of trying, she can't recreate her fiancé and the train keeps putting her number up higher and higher in response to her falling further and further into her demons. One-One also explicitly refers to the train as his mother, and while he does have control over some of its functions, he can't change its purpose or affect the numbers directly.
  • In Book 2, the train is shown to be able to seemingly exert a force upon M.T., Alan Dracula, and Mace that makes it physically impossible to move too far from the train itself, with Mace even saying that the train is doing it.
• Hard Light: The environments of the cars are solid holograms, generated by orbs that are usually hidden by the scenery.
• The Homeward Journey: The goal of most passengers is to escape the train and return home.
• Hybrid Monster: The Ghoms have the physical features of wolves and cockroaches.
• In Medias Res: When episodes aren't an immediate sequel, they're this trope, with the characters briefly alluding to the adventure they had in one of the many train cars explored during the interim.
• Idiosyncratic Episode Naming: Every episode follows "The (noun) Car" format, relating to whatever car (dimension) on the train is visited. Each season does have an exception or two, such as Book 2's "The Wasteland", but they still relate to something regarding the train.
• Improbable Self-Maintenance: Tulip (and other passangers of the train) remains well-groomed despite being trapped adventuring through the Infinity Train for months. According to Word of God, showers and laundry exist in some of the train cars but were found off-screen.
• In-Universe Catharsis: Ultimately, it seems this is the purpose of the train: to force people to confront their pent up trauma and negative emotions and finally move on. The only way to escape is to finally do so, the number of issues that they still have to deal with represented by a literal glowing green number on their hand, which opens a door to the home of the passenger when it reaches 0.
• Late-Arrival Spoiler: The train's purpose is implied in Book 1, and outright stated at the start of Book 2, to be the above-mentioned In-Universe Catharsis. The train appears to individuals who are experiencing severe emotional or psychological distress at a pivotal moment in their lives, with the journey through the cars meant to facilitate mental healing, growth, and change in an extreme version of adventure therapy.
• Left Hanging: Thanks to the show ending sooner than the writers expected, the conclusions to overarching plot threads like the status of Hazel after she left with Amelia to be quarantined and if Amelia ever gets her exit are left in the air. We also never get to learn more about One prior to his changing, which presumably Amelia's storyline would have touched on, and in terms of world-building, many hints dropped about the nature of the train, surrounding world, and what the Ghoms' purpose are, are left hanging.
• Logo Joke: The Cartoon Network Studios logo opens up to a POV shot of that season's core protagonist staring at their hand, with something changing about the situation as the season goes on. Books 1 and 2 only change them for the finale, while Books 3 and 4 change them for every episode.
• Loyal Animal Companion:
  • Book 1: Atticus the male Corgi dog towards Tulip.
  • Book 2: Alan Dracula the male deer towards both MT and Jesse.
  • Book 3: Tuba the female gorilla towards Hazel. After a little while, this starts to extend to Grace and Simon as well, until Simon brutally murders her.
• Magitek: What the train is. The train, while being incredibly technologically advanced, houses some supernatural elements such as the Chrome Car, which is a car that seemingly brings reflections to life.
• Mechanical Abomination: The train itself. It's an infinite train with cars the size of buildings running through another dimension, those cars are their own pocket universes, and it has some serious Blue-and-Orange Morality regarding getting over trauma. While we do eventually learn a little bit about how it functions, where it came from is completely unknown; it just is.
• My Instincts Are Showing: Many of the talking animal denizens are like this. Atticus is the eloquent leader of a nation, but he's also still a dog who loves getting his tummy rubbed and chasing balls. Likewise, The Cat is a long-lived trickster who still can't help but hiss and scratch things when upset.
• New Weird: An interdimensional train that kidnaps people and forces them to run a gauntlet of random and bizarre pocket dimensions until they work through their emotional trauma, is piloted by an AI with a Literal Split Personality, continuously builds new cars for itself, and is inhabited by everything from talking corgis and sentient blobs of water to mirror policemen and human-sized pencils with limbs.
• Next Sunday A.D.:
  • Book 1 canonically has Tulip board the train on November 22, 2019 and return home sometime in early Spring, while the series itself premiered August 2019.
  • Book 2 takes place in early Summer 2020, while the season aired in January 2020.
  • Averted with Books 3 and 4. The former both takes place and aired during Summer 2020, while the latter takes place in the 1980s.
• Once a Season: Each book has one episode that doesn't follow the naming format of "The _ Car" and is instead just "The _". The exceptions to this are Book 3 with "Le Chat Chalet Car" (although when translated from French it still counts, it also still ends with "Car"), and Book 4 with two episodes - "The Twin Tapes" and "The Train to Nowhere".
• Our Genies Are Different: A lot about the Mirror World denizens, as well as Lake's storyline in Season 2, give off a "genie/djinn" type of vibe, including the familiar "binding" versus freeing of a "Sliver," if in a way more Magic A Is Magic A way.
• Perpetual Motion Machine: The train only stops when passengers zero out and is in the middle of a barren wasteland, yet it's apparently been running for centuries and continually expands upon itself, growing ever longer as it produces new cars, with no apparent means of gathering resources.
• Power Trio:
  • Books 1 and 2 utilize this setup, starring a human passenger (Tulip and Jesse), a non-human entity who serves as a guide (One-One and Mirror Tulip (MT)), and an additional Loyal Animal Companion created by the train (Atticus and Alan Dracula). Book 4 foregoes the animal sidekick to use two human passengers (Ryn and Min-Gi) and an object denizen (Kez) instead.
  • Averted in Book 3, which has a Four-Philosophy Ensemble of three human passengers (Grace, Simon, and Hazel) and an animal companion (Tuba) instead. Tuba then dies halfway through the season and gets replaced by a fourth human passenger, Amelia. Hazel is also revealed to not be human at all, meaning that the setup was actually two humans and two denizens, followed by three humans and one denizen.
• Reality Warper: The train is able to appear anywhere in the real world it needs to, generating the necessary space and train tracks to drive there, and even taking whatever form would best entice its target to inspect it. This ranges from appearing on top of a university building roof as a futuristic train to showing up inside a police station with its cars stylized as royal carriages. Sometimes, it doesn't even need to generate adequate space; in Book 4, it appears in the space between the two cars of another train.
• Recurring Character: In a rarity for an anthology series. The Cat makes appearances in varying capacities in every book. One-One and Amelia Hughes are the same, though they also have one season each where they don't appear and are only alluded to (Books 3 and 2, respectively).
• Recurring Riff: The musical riff heard in the opening sequence (high D, B, high G, F#) plays repeatedly throughout the series, both in the rest of the soundtrack (specifically within the main theme tunes of each season) and in-universe as a method to control various mechanisms on the titular train.
• Rotating Protagonist:
  • Book 2 focuses on Mirror Tulip, first met in Book 1's "The Chrome Car.
  • Book 3 focuses on Grace and Simon, who were named in Book 2's "The Lucky Cat Car" and "The Mall Car" (respectively), after appearing in a Freeze-Frame Bonus in Book 1's "The Engine".
• Riddle for the Ages: While we learn the purpose of the train and even discover its inner mechanisms over the course of the series, who or what is responsible for the train's existence to begin with is never revealed.
• Talking Animal: Quite a few examples, but most prominently Atticus, Tuba (the Loyal Animal Companions of Books 1 and 3, respectively), and The Cat. This is averted, however, by Alan Dracula, the animal companion of Book 2, who does not speak.
• There Are No Therapists: Many of the problems the protagonists face could be solved if they were taken to a counselor or therapist. Instead, every single one of them gets thrown onto the therapy train to compensate.
• Unishment: The train has no punishment for its passengers acting rowdy. Whether they refuse to learn their lessons or are just outright malicious to the denizens or even other passengers, their only "punishment" is their number going up, which has no physical effects, it just delays their return to the real world. In fact, some passengers actually quite desire being on the train as opposed to going home to the lives that made them miserable in the first place.
• Vampiric Draining: The Ghoms are cockroach-dog creatures that can suck out the life force of passengers, and presumably other denizens, with their mouths.
• Video Game Caring Potential: Potentially. The train seems to be running something alike to a "virtual world," but there seems to be a "supernatural"/realistic/real life component to the denizens, and the extent is further questioned by what it means to project a world - for example, the mirror world possibly being a parallel world.
• Video Game Cruelty Potential: The flipside to the above, which is touched on in Atticus's mistreatment near the end of Season 1, "The Toad Car" episode of Season 2, and explored in more depth in Season 3. The Apex run wild harming the denizens, but especially considering the above-mentioned "supernatural"/realistic/real life components to the denizens, by the time the audience sees this treatment, it comes off quite eerie.
• Well-Intentioned Extremist: The train is ultimately this. It abducts people who actively refuse to deal with their personal problems, provides scenarios across the many cards to help them work them out, and sends them home once they have...but it can also keep them prisoner for decades, and offers very little guidance.
• Year Inside, Hour Outside: Discussed but ultimately averted, in contrast to many other works in this genre. Tulip mentions in "The Chrome Car" that she's been on the train for quite a while, but isn't sure what that means for the outside world. We later learn that time on the train and time back on Earth advance at the same rate, with it explicitly told and shown that Amelia arrived as a young adult in the mid-1980s and is now a middle-aged woman. When someone becomes a passenger, they are missing in the real world for as long a time as they stay on the train, even if that's years. Their friends and family do notice they're gone, passengers remember their time on the train, and physical changes like Tulip losing her reflection remain after they return.

Book 1: The Perennial Child

• Ambiguously Evil: The Steward is heavily armed and attacks without provocation, but it doesn't try to kill Tulip intentionally, only demanding she returns to her seat. It also flees at the sight of One-One. It turns out to work for the Conductor as The Dragon.
• Arbitrary Skepticism: Tulip constantly questions the logic (or, rather, the lack thereof) of the train, despite having traveled through dozens of different worlds by the third episode, wondering why arbitrary actions like singing would have any effect on their progress.
• Bait-and-Switch:
  • Tulip sees someone being sucked up into a vortex in the first episode and thinks it's a bad thing. It's actually a good thing, as it takes you home once you confront your traumas.
  • When she asks One-One about the significance of the number decreasing, he states that if it reaches zero, then she's gone forever...from the train, because it's not counting down how long she has to live but how much trauma she's currently going through.
  • A meta one appears at the end, as audiences were made to believe the show was a ten-episode miniseries until a "Will Return" Caption stated otherwise.
• Big Bad: The Conductor, Amelia. When she catches up with Tulip in the Ball Pit car, she indicates that everything is supposed to exist as she intended, and Tulip's pursuit of freedom by moving through the cars throws everything into chaos.
• Big Shadow, Little Creature: The giant monster that was scaring Atticus and his subjects turn out to be just a tiny spider, projecting a huge shadow with the help of a glowing orb.
• Bittersweet Ending: Tulip manages to return home and mends her relationship with her parents. However, Amelia will likely be trapped on the train for the rest of her life, it's unlikely Tulip will ever see One-One or Atticus again, and the "no reflection" thing is bound to cause problems.
• Book Ends: The season begins and ends with Tulip heading off to Coding Camp.
• Captain Obvious: Upon seeing the exterior of the train and a passenger getting vaporized, Tulip asks One-One what happened, with his reply being that she's in a bad place at the moment. Played with, as the "bad place" is Tulip's obviously troubled state of mind, not her physical location; it's later shown that the "vaporization" was the passenger lowering his number to zero and escaping the train.
• Chekhov's Gag: The first thing One-One does when he meets Tulip is ask if she's his mother. It goes on to be a running gag for the season, and it turns out that the mother he was looking for was the motherboard of the train, because he's the real Conductor.
• The Comically Serious:
  • Sad-One speaks in a monotone and often is The Eeyore. He also has some of the funniest one-liners.
  • To a lesser extent, Atticus. He's a regal, dignified king who also happens to be an adorable corgi and treats simple dog things with the utmost seriousness.
• Dark Is Not Evil:
  • Alrick; while he was shown wearing the black hoodie the Conductor is known to wear, was a sweet man. His wife, on the other hand...
  • One of the first unsettling sights that Tulip sees in the train dimension is a swirling vortex that absorbed a fellow passenger, making Tulip realize that she could possibly die on the train. The penultimate episode reveals that the vortex is a good thing, as it means you zeroed out your number and can finally return home.
• The Dragon: The Steward, to the Conductor.
• Early-Bird Cameo: Simon and Grace, with cut-off portions of their high numbers, briefly appear in the list of passengers on Amelia's computer screen.
• "Eureka!" Moment: Tulip briefly loses hope when the monster in the Corgi Car turns out to be a spider's shadow cast by a glowing orb, but after Atticus calms her down, she questions how a normal spider would even affect the water level, leading her to the Steward.
• Evolving Credits: In the vanity plate, Tulip stares at her hand as it quickly rotates through the numbers. The final end card has the number stop at zero, then fill the screen with a blinding light, returning her home.
• Exact Words: When Tulip asks the significance of the number, One-One states that if it hits zero, she's "gone forever", making Tulip think she's going to die. He meant gone forever from the train. He never said she was going to die. On a slightly lesser note, when Tulip asked One-One in the previous episode what happened to the vaporized passenger, his reply is that she's "in a bad place right now." He meant her mental state, not her physical location. Her mental state, of course, being an important factor in getting off the train.
• Fake King: The Conductor is actually train passenger Amelia, who overthrew the true Conductor, One-One, to try and make a car with a replication of her dead fiancé.
• Finish Dialogue in Unison: When Atticus attempts to explain the monster.
  Atticus: I will admit, there are some things I haven't told you about Corginia–
  Atticus and Tulip: Like why there's a giant shadow monster!
  Atticus: Yes. Patience, young lady.
• Fireball Eyeballs: The Steward has blue flames coming out of its eye sockets that are generated by a pair of valves behind its mask.
• Five Stages of Grief:
  • In a rare example where death isn't the cause, Tulip is stuck in Denial over her parents' divorce, trying to ignore everything to avoid facing the pain, occasionally slipping into Anger. By the end, she's moved on to Acceptance.
  • Amelia was originally in Depression following her fiancé's death, but by the present is stuck in Bargaining and Anger, and due to her power over the train as Conductor, is extremely dangerous because of it. Thanks to Tulip, she's at least starting down the path to Acceptance.
• Foreshadowing:
  • There are a few hints at One-One being the real Conductor, like his obsession with "fixing" the Unfinished Car, the Conductor/Amelia's obsession with capturing him, and how he was able to take control of Amelia's tape.
    • The fact that it's One-One that tells Tulip about the significance of the number. As Tulip stated, he made her think that she was going to die.
    • During the first encounter with the Steward in "The Corgi Car", it flees upon seeing One-One. It used to work for him until Amelia took over.
  • Tulip sarcastically mentions how her number is going down because she's "growing as a person" in "The Cat's Car". She's absolutely correct.
  • When Tulip comes dangerously close to crossing the Despair Event Horizon at the start of "The Past Car", her number starts to go back up because she's slipping back into the habits that led to her being unable to deal with her trauma. This turns out to be foreshadowing for "The Engine", where it's revealed that Amelia's own number has been increasing the whole time she was acting as the Conductor, and it's now so long it extends off her arm and onto her neck.
• Freeze-Frame Bonus:
  • When Tulip wakes up in "The Grid Car", for a split second you can see one of the mechanical pods which deposit new passengers flying behind some trees in the background.
  • During the first half of "The Ball Pit Car", for just a few frames you can see the shadow of the stewardess swoop by in the background after Tulip drags the other three up the rolling ladder. Her shadow appears again later in the episode in a porthole window off to the side.
  • In the final moments of the show, Tulip still doesn't have a reflection in the mirror.
• Funny Animal: The turtle people in "The Unfinished Car", though curiously they're led by a quadrupedal tortoise.
• Furry Reminder: The Cat and the corgis of the corgi car are intelligent and capable of human speech, but still act like their respective species and point out traits like their lack of thumbs when asked why they're incapable of certain tasks.
• Hard Truth Aesop: Tulip and Amelia both get a reality check about their problems: trying to pretend they don't exist or desperately undoing the past is impossible. Thanks to her parents' divorce, Tulip has become sullen and bitter towards them, believing everything was perfect and they ruined her life. She's forced to realize that, actually, the red flags were there the whole time and her parents are flawed but not malicious. Meanwhile, Amelia eventually realizes she can't bring her husband back, no matter what she does, and breaks down in Tears of Remorse over what she did.
• Ironic Name: The book's title refers to Tulip, but she only appears in this season and is ultimately the one who changed everything on the train from the Conductor's control after 33 years.
• Lightmare Fuel: The entire series provides examples of this, but pride of place should be given to giant, soul-sucking dog cockroaches playing musical notes and making colored blocks as they are thrown across the Grid Car.
• Literal Split Personality: One-One is a ball-robot with two personalities: Glad-One, the eternal optimist; and Sad-One, the eternal pessimist. The two personalities can split down the middle to function independently.
• Living MacGuffin: The reason why the Conductor/Amelia seeks to reclaim One-One is because he is a key component to stopping the train itself. One-One is the real conductor, and Amelia wanted to make sure he never had a chance to reclaim control of the train.
• Living Shadow: Subverted. The corgis fear the shadow monster that raised the tides, but the beast is actually just a spider whose shadow was being cast by a light; the actual cause of the problem is a tentacled robot.
• Lotus-Eater Machine: Tulip's videotape full of false but happy memories was intended to be a gift to bring her everlasting happiness, with other such tapes existing. The train itself is arguably one for its native inhabitants as well, with every car serving its purpose with the intent of keeping its denizens placated. "The Engine" reveals dozens of passengers exist on the train simultaneously, but the infinite nature of the train means Tulip never met them.
• Mathematician's Answer:
  Tulip: How does this door work? Are you like a real robot? Are there other people on here? Is this what trains are like?
  Glad-One: Yes!
  Tulip: Yes to what? Which?
  Glad-One: I dunno.
• Metaphorically True: When Tulip asks what the number means on her hand, One-One states that she'll be gone forever if it goes down to zero. In the sense that the old self filled with trauma will be gone forever and she'll be reborn as a new person.
  • It can also be interpreted to mean that Tulip would leave the train and never come back.
• Mood Whiplash: "The Ball Pit Car" starts off mostly lighthearted as Tulip, One-One, and Atticus play around through a ball pit funhouse, and then the Conductor shows up...
• Mundane Solution: Some of the more benign inhabitants of the train, such as One-One or Atticus, have no idea how to exit their respective cars due to... their inability to reach or turn the door handle.
  Tulip: ...That's how all doors open!
  Atticus: [mildly offended] My people have been working on this technology for decades.
• New Content Countdown Clock: The U.S. television premieres had the episodes of The Amazing World of Gumball which preceded them feature these.
• "Not So Different" Remark: After watching Amelia's tape, Tulip is at first angry because she didn't want to feel bad for her, preferring to think of The Conductor as "some heartless robot thing", but now she realizes that Amelia is having her own trouble adapting to the changes in her life, running away out of fear just like Tulip herself. It's this realization that ultimately brings Tulip's number all the way down to 0 and opens her exit car containing the portal that will take her back home.
• Ontological Mystery: Tulip is stuck on the train with no idea what it is or how to leave. She also has a glowing number stuck on the palm of her hand that has no immediately discernible meaning. The number turns out to be representative of the issues that Tulip is refusing to deal with, and once she manages to overcome them, the number reaches zero and a door home opens.
• Parental Issues: It's clear in the first episode that Tulip is not taking her parents being divorced well.
• Pensieve Flashback: How the passengers' memory tapes work when watched.
• Rewatch Bonus:
  • A good chunk of One-One's more non-sequitur dialogue has Double Meanings that, upon rewatching, reveals itself to have been foreshadowing and/or straightforward explanations of various elements of the train when placed in the proper context.
  • Every background detail in "The Unfinished Car" directly references various elements of Amelia's past. Most are of moments directly shown in "The Past Car" in either snapshot or full flashback; from all the places and items she and Alrick interacted with, no matter how minor, to even bits of conversations. Meanwhile, a handful of background details reference parts of her past that are only vaguely alluded to, such as her spending time at the hospital after Alrick's accident.
• Ridiculously Cute Critter: Corginia is a kingdom full of sentient corgis that like to lie in the sun and have their belly rubbed. The sole "ugly" inhabitant isn't even ugly; he's only referred to as such because he's a different breed of dog.
• Robot Buddy: One-One is Tulip's ditzy robot sidekick.
• Royals Who Actually Do Something: Atticus personally joins Tulip to defeat the monster and braves the Steward's machine-gun fire in a valiant, but ultimately futile, attempt to attack it. Once the Steward escapes, he joins Tulip's journey to the train's engine so that he can assure that it will never do damage to his kingdom again.
• The Runaway: After a scheduling error kept either of her parents from taking her to a video game design camp like they had promised, Tulip decides to try and head there by herself, which is how she finds the train.
• Samus Is a Girl: In "The Past Car", the Conductor is unmasked as Amelia, who deposed the original conductor One-One.
• Soundtrack Dissonance: While Tulip is running from the Ghoms, One-One suddenly starts humming "Yakety Sax".
  Tulip: What are you singing!?
  One-One: It's a wacky getting chased song. I made it up.
• Stealth Pun: Tulip's dad affectionately calls her "bud". As in a tulip bud. It could even be considered a Multiple Reference Pun, as it echoes the expression "budding genius".
• There Is Another: It's nonchalantly revealed that Tulip isn't the only passenger in "The Cat's Car". It turns out the Conductor is one of them.
• Those Two Guys: One-One and Atticus sometimes act this way when the focus is just on Tulip.
• Token Black Friend: We only see Mikayla in the first episode, helping to serve as exposition for Tulip's intentions. She also happens to be black.
• Trademark Favorite Food: Tulip is repeatedly seen eating raw onions, and one of her altered memories in "The Cat's Car" shows her mom presenting her with double onion ice cream cake. She even has an onion-shaped eraser on the end of her pencil.
• Tragic Villain: Amelia lost her fiancé and found herself onboard the train. She became the Conductor and tried to create a perfect world where he was still alive and they could live happily. Her sadism appears to simply be one way she fills the void he left in her.
• Wedding/Death Juxtaposition: As Tulip is watching Amelia's memories, she sees a moment where Amelia proposes to Alrich. The image quickly shifts to people trying to talk to Amelia about the pending funeral for Alrich.
• Wham Episode:
  • In "The Ball Pit Car", the Conductor reveals herself to be the Big Bad, demoralizing Tulip for messing with her "plans", and turning poor Atticus into a Ghom.
  • In "The Past Car", we learn the truth about the Conductor.
• Wham Shot:
  • "The Past Car" has Tulip see the memories of the Conductor, with someone wearing a black hoodie entering the train. Much to her surprise, it's not Alrick — who was shown wearing a black hoodie and speaking with a robotic voice similar to that of the Conductor — but his wife, Amelia.
  • How big of a number does Amelia have? It's gone past her arm and up to her neck.
• "Will Return" Caption: The original television airing of "The Engine" had a short promo clip air before the credits sequence, telling the audience this.
  One-One: Back as Conductor and better than ever! See you next time!
  Infinity Train Will Return
• White-and-Grey Morality: Tulip quickly develops into an incredibly kind, empathetic person on the train, whereas Amelia is a Tragic Villain who is motivated only by the grief of her deceased husband and begins the path to redeeming herself at the end.
• You Need a Breath Mint: Tulip's habit of snacking on raw onions earns her this remark from her friend Mikayla.
• Your Days Are Numbered: Subverted. After a comment from One-One, Tulip becomes convinced that the numbers on her hand are counting down to her death. When she tells this to The Cat as part of her plea for help, the feline points out that One-One isn't the smartest or most optimistic being out there. It turns out that the number actually indicates the weight of your emotional trauma. However, Amelia notes that the number can also go up...
  Tulip: One-One! You made me think I was gonna die!
  Sad-One: It'd be surprising if you never died.

Book 2: Cracked Reflection

• And Then What?: Discussed in "The Wasteland", when Mace points out that even if MT successfully escaped the train, her metal skin means that she'd be unable to have a normal life alongside Jesse in the real world. MT is unable to muster up a counterargument but insists she'd figure something out.
• Arson, Murder, and Jaywalking: One-One explaining to MT the process of waking up a passenger.
  One-One: It involves robots and coding and juice boxes and...
• Big Bad Duumvirate: Special Agent Mace and Agent Sieve, who were Villains of the Week in Book 1, ascend to main villain status, where they relentlessly hunt Mirror Tulip as she attempts to escape the train.
• Black-and-Gray Morality: MT is a Pragmatic Hero and Jerk with a Heart of Gold who is willing to do pretty morally questionable things in order to assert her independence, but also demonstrates herself to be a decent person inside. The Flecs are the only unsympathetic major villains in the series and intent on killing her for the "crime" of attempting to be an independent person.
• Body Motifs: Throughout the season, MT repeatedly looks down at her reflection in her hand for self-examination and contemplation. Plus it's the only way she can look at herself without risk of summoning the Flecs.
• Bowdlerise: The scene in "The Wasteland" where MT kills Mace by grinding him against the train wheels was cut out of Latin American airings.
• Break Them by Talking: In "The Wasteland", Mace does this throughout the entire episode to MT. From drilling her on how she plans to live a normal life when she isn't actually human, to claiming that she's just traded in being a literal reflection to being a metaphorical one for Jesse and other passengers. But rather than demoralize her, it ends up giving her another idea to try out.
• Brick Joke: In "The Black Market Car", MT sees a new passengers that appears to be a lunch lady. In "The Map Car", Jesse describes an old lunch lady he knew and muses about her possibly being a passenger as well.
• Call-Back: Most of the denizens and carnival games seen in "The Lucky Cat Car" serve as this for Book 1 and "The Train Documentaries".
• Central Theme:
  • Independence. MT is trying to rebel against the Mirror World's corrupt and totalitarian views, wishing to be her own person instead of being forced to become something she's not or being killed. Jesse also has to learn that not being able to please everyone is okay, since he was an Extreme Doormat who allowed his "friends" to take advantage of him and hurt his little brother.
  • Identity. Much of the season also surrounds MT trying to define herself as her own person separate from Tulip or anyone else, not only rejecting the myriad of labels everyone else tries to give her, but also trying to establish that she has actual worth as a living being when both the Mirror World and the train insist that she doesn't.
• Chekhov's Skill: Alan Dracula's Eye Beams and constant craving for grass end up helping MT and Jesse escape from the Flects one final time as they attempt to take the exit to Jesse's home. When Sieve grabs MT by the ankle right as she's halfway through the door, she grabs some grass from the ground and throws it back through the portal to get Alan Dracula's attention. He then uses his eye beams to finish off Sieve.
• Contrasting Sequel Antagonist: The Mirror Police's tenure as main villains is much different from the Conductor's. The Conductor was shrouded in mystery, only interacting directly with the protagonists towards the end; their goals and intentions were obtuse for the longest time and Tulip only represented a minor setback towards them; their actions effected the entire train and they answer to no one but themselves. In stark contrast, Mace and Sieve are recurring threats from the first episode of the season, their intentions are immediately clear with capturing MT being their explicit goal, they do their best to minimize interactions with other inhabitants and passengers whenever possible, and they're working on behalf of a greater organization.
• Continuity Nod: The various cars that appear in photos that Jesse has taken during his stay are ones that appeared in the "The Train Documentaries" shorts that aired between Books 1 and 2, such as the Cross-Eyed Ducks Car and the Green Car.
• Cult of Personality: The Apex have sort of formed one for the previous Conductor, seeing One-One as a usurper. Instead of trying to fix their problems, they make their numbers go up by causing mischief on the various train cars. They also have a sound wave marked across the middle of their face, denoting the analogue hijacking noise she used to control the Steward.
• Double-Meaning Title: The name 'Cracked Reflection' applies to both MT and Jesse. MT is essentially "cracked" because she took a third option, breaking the rules of the Mirror World to enter the real world. Meanwhile, Jesse is figuratively a "cracked mirror" as he's a people pleaser who copies even the awful behaviors of his peers in order to better fit in and be more likeable.
• Earn Your Happy Ending: It takes a lot of work, and they go through a lot to do it, but MT manages to escape from the train and is now free to be with Jesse in the real world without the threat of the Mirror Police showing up whenever she reflects in something.
• Evolving Credits: In the vanity plate during the end credits, MT stares at her hand, with her downtrodden frown reflected back at her. The final end card has her give a relieved smile, her surroundings no longer that of the train but of the meadow by Jesse's home.
• Family-Unfriendly Death: Both Mace and Sieve suffer from this, the former grinded into the wheel of the train and the latter hit by laser beams and exploding.
• Foreshadowing: MT often looks at herself in her hand when thinking. In "The Number Car", her reflective hand lets her use Jesse's number as her own to escape the train.
• Internal Deconstruction: Much of Book 2 examines exactly how the mechanisms of the trains work from the perspective of the denizens. The train's occupants each live rich and elaborate lives, but as far as the train itself is concerned, they exist entirely to help passengers. They either bond deeply with new friends only to lose them or experience extreme brutality at human hands.
• Logic Bomb: Being forced to leave M.T. when she couldn't follow him through his door was so emotionally traumatizing to Jesse that he actually ended up back on the train. Because his problem is leaving M.T. behind, who can't have the number that she needs to leave because she's a denizen of the train, his new number can't even settle on a rational number instead of things like a square root or pi. Trying to figure out the issue drives One-One into such a loop that it even physically affects the train. Jesse even restarts the recursive loop when the One-One starts to agree with a suggestion that killing M.T. would resolve the issue.
• Loophole Abuse: M.T. manages to get a number by holding Jesse's hand in such a way that his number reflects into her hand. Since it solves the aforementioned Logic Bomb, One-One allows it.
• Magical Security Cam: The Mirror Agents can locate MT when she passes by any reflective surface, so she carries a can of black spray paint in order to coat all such surfaces to prevent this from happening. Her own surface is the only exception to this.
• Meaningful Rename: MT chooses to rename herself "Lake" after getting off the train, referencing the fact that she can now enjoy the sight of a lake and any other reflective surface without worry. Doubles as a Line-of-Sight Name, as she chooses the name after staring into a nearby one.
• Mini-Mecha: The Steward returns near the end of the season, filling this function for One-One.
• New Content Countdown Clock: Like with the first season, the U.S. television premieres had the episodes of The Amazing World of Gumball which preceded them feature these.
• Reflective Teleportation: Agents Sieve and Mace, "mirror cops" from the Chrome Car, can emerge from any reflective surface, including water, while chasing and apprehending rogue reflections. As a precaution, M.T. carries around black spray-paint to use on shiny surfaces to ensure the two won't come for her.
• Ship Tease: Subverted, as the writers intended Jesse and MT to be platonic. This doesn't stop the audience from viewing the constant hand-holding and blushing, Agent Mace mockingly calling Jesse MT's boyfriend, and Jesse having to come back to the train because he was so torn up about leaving MT behind as signs of romantic interest.
• Shoo Out the Clowns: Once Jesse leaves the train, things get darker fast.
• Stern Chase: The overarching threat of the season is that MT is constantly being hunted by the Reflection Police.
• The Tape Knew You Would Say That: One-One's tape for new passengers has shades of this regarding the first questions they have after waking up, though he quickly gets sidetracked from their actual concerns.
• Time Skip: The season begins two months after Tulip has already left the train.
• Toxic Friend Influence: Part of the reason why Jesse is on the train: he desires so much to fit in that he'll willingly engage in behaviors that he knows are wrong.
• "Wanted!" Poster: One of these is found in the Black Market Car. MT takes it and puts it in her pocket, which Jesse later finds in "The Toad Car" when the Flects are chasing them and it falls out.
• The Watson: Jesse serves as an excuse for M.T. to explain a few things about the Mirror World.
• Wham Episode:
  • "The Mall Car" ends with Jesse leaving the train but MT rejected from the exit, with the final shot being MT crying on the ground while the Flects stand over her, ready to take her down.
  • The following episode, "The Wasteland", has the show's first instance of Killed Off for Real via MT grinding Mace into nothing on the train wheels.
• What Measure Is A Nonhuman: The running theme of the season. Denizens of the train are explicitly stated by One-One to exist solely to help passengers get their number down, regardless of the fact they are fully sentient beings that often develop motivations past that. Some don't try to fight it and are fully accepting of their role (the Reflection Police), others try to manipulate the system to find at least some personal gain and satisfaction (The Cat), and still others reject the system entirely and wish to escape (MT). Beyond that, members of The Apex refuse to acknowledge the sentience of these beings and view them as nothing more than fancy toys.
  • In a meta context, it's precisely the fact that they aren't human which allowed for the violent deaths of Mace and Sieve.
• Yank the Dog's Chain: At the end of "The Mall Car", Jesse zeroes out his number and unlocks his exit. Unfortunately, as they run through it, they learn MT is physically unable to pass through the door with him. Jesse is forced to leave without her, disappearing while they desperately try to hold each others' hands.

Book 3: Cult of the Conductor

• Alas, Poor Villain: Simon. He dies at age 18, as a confused underdeveloped child, to the trauma that caused his Start of Darkness and haunted him his whole life without ever getting the help he needed. It doesn't help Simon died crying thinking he'd permanently lost his Only Friend and that he was alone. Writer Lindsay Katai says Simon's death was written as a tragedy unlike the death of Mace and Sieve. Even In-Universe, Grace sobs over Simon's ashes.
• Androcles' Lion: At the beginning of Episode 10, after Grace admits her flaws and is free of her memory tape, she helps fix the denizens of the Origami Car that Simon stepped on and crumples. At the climax of episode 10, those same origami denizens are the reason Grace survives the season; Simon kicks Grace off the train to be wheeled the same way as Tuba, but Grace survives because the origami birds grab her and fly her back up to the train.
• Anyone Can Die: And how. By the end of the season, two of the book's four poster characters are dead. Tuba is murdered halfway through, while Simon perishes in the final episode. Grace and Hazel don't die, but the former is victim to two murder attempts, while the latter's innocence is buried six feet under.
• Bait-and-Switch: The goal of Grace and Simon is to follow the cluster of numbers that will lead them back to the Apex. It turns out what Simon was detecting wasn't the Apex, but Amelia because of her humongous number.
• Bait the Dog: The Book serves to flesh out and humanize the Apex more. Simon, in particular, has a number of sympathetic moments showing how he cares for Grace and the audience learns that he's been trapped on the train since he was 10. In "The Color Clock Car", he finally starts to warm up to Tuba, sharing a laugh with her and helping her through the car. The episode ends with Simon killing her by throwing her under the wheels of the train, obliviously talking about killing her adoptive mother to Hazel, and it's all downhill for the remainder of the season.
• Big Sister Instinct: Grace develops this for Hazel as the season continues. When Hazel decides to leave her and Simon in the penultimate episode to go with Amelia, Grace is completely devastated from losing her.
• Bittersweet Ending: On the positive side of things, the Apex has been more-or-less disbanded. Grace and the children are now working to figure out how to move forward and help each other get off the train, Grace's number has gone way down (from in the millions in the beginning of the season to only a few hundred by the end) and Grace herself now has a denizen partner in an origami bird. However, getting to that point forced Grace to deal with the death of a sapient denizen she was slowly growing attached to, being mercilessly rejected by a child she had grown to earnestly care for as an adoptive sister and will now never see again, almost getting killed by her best friend, and then watching said best friend die himself by literally crumbling into dust. And even if Grace fulfills her mission, she will forever live with the fact that everything she did was all her fault, and she will return home to a family who may have all but forgotten her and a world she must adapt to with little to no resources and education at the ready. To say nothing of how the children she's indoctrinated will adapt back into society themselves or the fear that their families may have forgotten about them too. No wonder the final shot is Grace giving them all a melancholic and uncertain smile.
• Black-and-Gray Morality: Oscillates between this and Gray-and-Gray Morality. While Simon is an incredibly broken Tragic Villain, he is still a vile pathological narcissist who commits horrific crimes while refusing to see the wrongness in his ideology. However, Grace's hands are far from clean as she guided him into the ideology to begin with along with having killed hundreds of Denizens at this point.
• Breaking Old Trends: Book 3 has several changes to the formula established by the first two:
  • It's the first season to not have a Power Trio of main characters consisting of one human who needs to escape the train and two denizens who help them do so, instead being a Four-Temperament Ensemble. In addition, while said trios were very close True Companions by the end of their adventures, this is decidedly not the case for this season's main characters.
  • It's also the first season not to have a character zero out their number and escape the train at the end.
• Brick Joke: In "The Mall Car", Grace tells Jesse to be careful where he aims the harpoon or he'll "end up like Lucy". Sure enough in "The Musical Car", one of the Apex girls, named Lucy, has an eye patch.
• Call-Back:
  • Jesse's name can be seen in "The Musical Car", as the composer of an opera entitled "Empathy Goes", with the song they perform ("When I Look at You, I See Me") being one he referenced in Book 2's "The Family Tree Car".
  • The Apex have the Unfinished Car from Book 1 as the second one that they raid in the first episode. There are also corgis there, additionally calling back to how Atticus befriended King Aloysius and promised to send aid to rebuild following the events of that episode.
  • The Jungle Car where Grace and Simon meet Hazel and Tuba is the same one depicted in the Book 1 poster.
  • In "Le Chat Chalet Car", The Cat is still angry at Grace's actions over what happened in "The Lucky Cat Car".
  • The Canyon of the Golden Winged Snakes Car in the seventh episode is the same one that MT visits during her travel montage at the beginning of Book 2.
  • The Cat gives Simon a tube filled with the memory extraction robots first seen in "The Tape Car".
  • Amelia's reign as the Conductor is why cars are being ejected, as One-One is having any car she made quarantined.
  • Grace gets trapped in her own memory tape, just as Tulip did in Book 1. Grace has very similar experiences in said tape, such as distorted memories and the static almost consuming her.
• Central Theme:
  • Empathy. The book starts off with a musical number detailing the joys of understanding other people, and the rest of the season tackles Grace's and Simon's struggles to learn empathy for denizens of the train. By the end, Grace has learned this lesson, while Simon's Lack of Empathy for denizens only gets worse and quickly expands to Hazel and Grace, unable to understand why they're beginning to fear and distrust him following his murder of Tuba. Ironic, considering that "Le Chat Chalet Car" has him begging Grace to be emphatic towards his fears and trauma. More over, when you use dehumanizing words like "Null", then it means that you remove people's empathy for someone else; notably, Grace stops using that term and respectfully starts using "denizen" to prove that she's changing.
  • Poor parental figures and caretakers. Grace alludes to her parents being inattentive, while Simon's parental figure on the train (the Cat) abandoned him to fend for himself. Hazel doesn't remember her parents, but we later learn that she is a failed clone of Alrick, with Amelia refusing to acknowledge her as a child, much less being anything akin to a daughter (but that doesn't stop her from taking Hazel with her). More broadly, Grace and Simon are the only source of guidance for the children of the Apex, and act more as manipulative cult leaders than caretakers until Grace's Heel–Face Turn changes all that. The only healthy parent-child relationship shown during the season is Tuba as a surrogate mother towards Hazel.
  • Coping with shifting worldviews. The Apex hold the idea that numbers are a symbol of power and that the train exists as a playground for their personal amusement. By the latter half of Book 3, Grace has started to realize that this perspective is childish and has terrible consequences, ultimately apologizing her actions and working to reform the Apex. Whereas Simon refuses to face the truth that they've been wrong and doubles down on his behavior, which leads to his death.
  • The damage that lies can do. The lie that Grace told a young Simon in "The Origami Car" is what would kickstart the entire Apex project because she never wanted to admit that she could ever be wrong. Her lying about not knowing about Hazel being a denizen results in her relationship with both Hazel and Simon being ruined. Simon rejecting the truth and becoming consumed by the lie that he's always right ends up in his death.
• Children Raise You: ZigZagged. Grace and Simon are much more inclined to manipulate children than actually become better for them, but they start to soften and open up after spending extended time with Hazel. Only for Simon to continue indulging in his old behavior and become even worse, while Grace continually chooses to save face in front of Simon over outright protecting Hazel. The poor girl ultimately abandons the duo, realizing neither are capable of providing the care and protection she needs. Only after overcoming her problems on her own does Grace truly thrive as a caretaker.
• Cult of Personality: As noted back in Book 2, the Apex is one formed around the previous Conductor, seeing One-One as a usurper. Instead of trying to reduce their numbers, they believe they must increase them by causing mischief on the various train cars. They also have a sound wave marked across the middle of their face, denoting the analogue hijacking noise she used to control the Steward. When Amelia finds about it, she laughs at how ridiculous it all is.
• Darker and Edgier: Featuring two outright villains as our protagonists, this is the darkest book so far. By the end of the season, all of the main quartet has suffered to some degree: Tuba and Simon are killed (one murdered by the other, the other graphically killed by a Ghom), Hazel has become thoroughly jaded and distrustful of the world, and Grace is a victim of attempted murder at the hands of her closest friend. While the other seasons still have their moments of levity towards the end, Book 3 abandons comedy entirely for its final two episodes.
• Does This Remind You of Anything?:
  • After Simon kills Tuba, he becomes much more aggressive, gets into Grace's personal bubble and is mad that she's "not the way she's supposed to be". Combined with Hazel wanting to be strong to protect her and Grace, he comes off as an abusive boyfriend/husband, not helping that Grace is keeping secrets from Simon out of fear.
  • In "The Origami Car", Simon uses the nanobots that The Cat gave him to send Grace into her own tape against her will. He inserts himself into her memories, intentionally uses some particularly painful ones to break her will, ignores all her objections, and then just leaves her to rot when he gets what he wanted. The whole scene carries some horrifying parallels to assault, especially when Grace later wakes up, visibly disgusted and shaken by the whole affair.
• Dramatic Irony: The Apex raid the Unfinished Car in the first episode... the car made by the Conductor they just so happen to worship. In fact, everything Grace and Simon tells about the Conductor to Hazel in "The Debutante Ball Car" is just filled with this and the "drama" being in that it's hurting rather than helping.
• Evolving Credits: The vanity plate during the end credits now continually changes throughout the book, showing off the current states of the protagonists. The background changes each episode as well, reflecting the car in which the characters find themselves in that moment.
  • "The Musical Car" has Grace and Simon's hands shown, with their huge numbers on display.
  • Starting from "The Jungle Car", Hazel and Tuba show their hands as well, with Grace and Simon's lit numbers contrasting with Hazel's unlit number and Tuba's lack of one.
  • Starting from "Le Chat Chalet Car", Grace's hand now hidden underneath her gloves, as she decides to keep it hidden after realizing it's going down.
  • Starting from "The Color Clock Car", Tuba's hand no longer appears and Hazel's now reflects her turtle transformation. And whereas Hazel's hand was happily waving in previous episodes, it now quivers uncontrollably.
  • Starting from "The Campfire Car", Amelia's hand is shown, as she is now interacting with the group.
  • "The Origami Car" has only Simon and Grace's hands present, due to Hazel and Amelia leaving at the beginning of the episode. Simon's number is rapidly climbing, while Grace's hand is being consumed by static.
  • "The New Apex" has only Grace's hand depicted following Simon's death, now uncovered and showing her number rapidly falling.
• Family-Unfriendly Death: If you thought Mace's death was bad, this season is even worse! Simon's death is not pretty, as his skin and eyes graphically melt and his bones are turned to ash right in front of Grace and several of the kids.
• Foreshadowing:
  • The Downer Beginning has a Tragedy Mask be the only survivor of the massacre by the Apex. Grace is the only protagonist left at the end of the season as the other main characters either died or left the group. Not to mention that the entire Book is nothing but a tragedy.
  • Much of Hazel's seemingly random bits of trivia are direct references to Freeze Frame Bonuses from Book 1's "The Past Car" and thus hint towards her relation to those characters.
  • Simon's experiences in "Le Chat Chalet Car" further fire his desire to kill Tuba in a misguided attempt to prevent Hazel from going through his trauma of being abandoned. Also in that car, he encounters a statue of a Ghom and briefly panics, thinking it's real. At the end of the season, a Ghom kills him.
• For Want Of A Nail: All over the place. For example a younger Grace in "The Origami Car" lied about how the numbers worked instead of admitting that she herself had no idea, leading to the gullible and emotionally vulnerable believing her fullheartedly eventually leading to the ideology of the Apex years later.
  • Moreover, had the Cat either returned to Simon or at least imparted the knowledge on what the numbers meant, he wouldn't have become so attached to Grace and probably would've either left the train sooner or corrected Grace's "I'm a total expert on the train" bluff.
  • The entire arc stems on the fact that of all cars Grace decided to enter (The Unfinished Car), it was just when Amelia used her pulse to send it to quarantine.
• Given Name Reveal: "The Canyon of the Golden Winged Snakes Car" has Simon call The Cat Samantha.
• Gory Discretion Shot: Unlike the death of Mace in the previous season, the death of Tuba is not seen, instead having lightning crash to depict it.
• Hard Truth Aesop: Sometimes people you love who need help due to childhood trauma will continually reject help even though they deserve a chance at redemption, dying without ever turning their life around.
• Honesty Aesop: Grace realizes that her lies and bluff that she totally knows the rules of the Train all those years ago led to numerous children being brainwashed to hurt people and being separated from their families just for her amusement and ultimately ended with Tuba dead, Hazel's innocence destroyed and Simon dead. All because she couldn't suck up her pride. Lesson learned: if you don't know anything, never give people false hope by being a Know-Nothing Know-It-All or else they may be completely convinced that that truth is the only truth and you'll have to see everything you created be turned to ash in a heartbeat.
• Internal Reveal: While the audience is already well aware of how the train functions and what the numbers actually mean by this point, Grace and Simon don't learn the truth until Amelia explains everything in "The Hey Ho Whoa Car."
• Know-Nothing Know-It-All: The Apex are convinced that higher numbers are better and mean power, despite it not being possible for that to be further from the truth. "The Origami Car" reveals that this started when Grace met Simon and acted like she got her number that high intentionally rather than admit to being clueless about how the system worked.
• Late-Arrival Spoiler: Mentioning anything about Amelia's role in this season spoils the end of Book 1.
• The Little Detecto:
  • Simon has a device that can track passengers by their numbers. Amelia's is so large that he mistook her for the entire Apex.
  • Amelia has a scanner that can detect anomalies, things that she created during her time as the Conductor.
• Meta Twist:
  • The Wham Episode of the last two books, each featuring some sort of death scene (Atticus and Mace, respectively) in their eighth episode. This time, the death scene happens in Episode 5, though Episode 8 is still a "Wham Episode" in its own right.
    • Instead of one major death, we get two: Tuba and Simon.
  • While Grace makes significant progress on this front, none of the passengers seen this season manage to get their numbers down to the point of leaving the train.
• Moment of Weakness: Throughout Season 3, Grace becomes a sister figure to Hazel. While at first Grace was manipulating Hazel with kindness, she starts genuinely caring about her. After Simon wheeled Tuba (Hazel's companion and adoptive mother figure), Grace learns that Hazel is a denizen who she and Simon view as inferior to passengers, but she keeps it a secret from Simon to protect Hazel. In a pivotal moment in the episode "The Hey Ho Whoa Car", when Hazel starts stressing out and transforms into her turtle self in front of everyone, Grace acts surprised so Simon would not know that she know Hazel's secret. When Simon suggests that they leave Hazel with Amelia, when Hazel asks Grace if she'll really leave her, to save face in front of Simon, Grace angrily says she will and calls Hazel a Null, breaking Hazel's heart. Grace is immediately horrified by her backslide, but does not apologize to Hazel with Simon there. In the next episode, Grace thinks on it and decides that she wants to protect Hazel even knowing what she is and what her mere presence does to the cars. But the damage was done and the bond of trust Hazel had with Grace is gone. Hazel rejects coming with Grace, choosing to leave with Amelia despite Grace begging to come with her. Hazel just sadly says goodbye to Grace, leaving her heartbroken.
• Mutually Unequal Relation: Exploited. In the first episode of Season 3 "The Musical Car", after raiding a musical cart, many of the young Apex kids offer items they took from the cart to their leaders Grace and Simon. Grace, who knows the children by name, acts like she has a special relationship with all of them, promising to cherish each item they bought her and store them in her special collection, while telling the child to keep it a secret from the other children that she's doing that. This is an act to make the children loyal to her, as once they leave, she discards them without a care.
• Poor Communication Kills: Much of the drama with Simon happens from either others telling him information or him misunderstanding what other people want. Most notably if Grace had told him not to kill Tuba period, or Simon had understood Tuba wasn't going to abandon Hazel like Samantha did him, much suffering could've been avoided.
  • The Cat does this literally to Simon; had she not abandoned him or at least told him what the numbers meant, it wouldn't have caused him to become who he is today and lead to his death to the hands of a Ghom years later.
• Psychopathic Manchild: Both Grace and Simon, who barely qualify as adults at age 18, are emotionally stunted childish adults with a infantile view of the world, a distrust of grownups and a habit of raiding cars and attacking the residents. Justified as they grew up without parents for 10 years and never finished 4th grade. Simon in particular has both a hatred of parental figures, yet also a hidden desire for one due to childhood trauma he never recovered from.
• Protagonist Journey to Villain: Downplayed with Simon, who was already a Villain Protagonist from the start, but like Grace, has some redeeming qualities and sympathetic traits shown during the first half of the season. But a combination of being reminded of his traumas and his paranoia getting the better of him leads him to double down on his pre-existing hangups and hurt Grace under the delusion that she was going to abandon him. The second half sees him undergoing more Sanity Slippage and becoming worse and worse, until he eventually takes up the mantle as the Big Bad of the season and tries to kill Grace, his Childhood Friend and then have a mentally breakdown shortly before being consumed by his lifetime trauma.
• "Ray of Hope" Ending: While Simon and Tuba are dead and Hazel is broken but in good hands with Amelia, Grace decides to reform the Apex after realize how her lies and haughtiness has hurt more than helped. Instead of staying on the train, they decide to help each other get home. After the credits, we see Grace's number rapidly decreasing.
• "The Reason You Suck" Speech:
  • The beginning of Episode 10 contains one for Grace, as she's confronted by a nightmare-version of Hazel yelling at Grace for her manipulative and cowardly behavior. The nightmare Hazel even accuses Grace of killing Tuba, to which Grace responds by pointing out that it was Simon who killed Tuba. Hazel retorts that while that's true, "He didn't come up with the idea to wheel denizens on his own!"
  • The climax of Episode 10 contains one for Simon, as Grace tells him that while he's in a lot of pain and Grace can see that, she is not responsible for all his problems and she does not owe him anything.
• Redemption Quest: For Grace, as they progressively undergo Character Development and become a better person over the course of the season, making a Heel–Face Turn by the end.
• Reformed, but Not Tamed: Amelia is trying to be a better person, but 30+ years of limited social interaction has not helped things, and she has a card by One-One to remind her that the passengers matter. She also doesn't do anything to fix up the messes she made with the Apex either
• Rewatch Bonus: Upon first watch, viewers might notice that Hazel talks with distinctly British phrasing despite not having an accent. This is likely due to her status as an imperfect clone of Alrick.
  "Don't be daft!"
  "He's a good sort, but barking mad."
• Rule of Symbolism: The Apex usually stick to one car and only travel to others before going back either to gather supplies or for kicks, showing that they rather stay in their comfort zones than actually grow. Once Grace admits what's going on and that they need to change, they decide to leave the comforts of the Mall Car to head out into the unknown, signaling that they want to change.
• Ship Tease: Grace and Simon mix with this with Childhood Friend Romance. They grew up together on the train and in the present frequently trade flirtatious remarks whilst giving each other coy looks or getting touchy feely with each other, with Simon even blushing around Grace sometimes. They even have a Dance of Romance. The writers have also said they "had a history" when asked if they were a couple and a deleted scene shows the two having an awkward First Kiss with each other. Simon's sanity slippage and death means this goes nowhere.
• Shoo Out the Clowns: Hazel leaving with Amelia at the start of Episode 9 is when things start getting darker fast, not that they weren't dark enough already by that point.
• Villain Protagonist: The two main characters of the season, Grace and Simon, are members of the hedonistic Apex, which is sadistic and cruel to the train's denizens. Over the course of the Book, Grace gets better and performs a Heel–Face Turn by the end, while Simon gets even worse and becomes the Big Bad.
• We Used to Be Friends:
  • Simon and The Cat were close when the former first came to the train, as she was his denizen companion. But after she accidentally abandoned him when they were running from a Ghom and never came back to save him, he became extremely bitter and grew to resent not just her, but all the train's denizens.
  • By the end of the season, Grace and Simon — best Childhood Friends, with implications of a romance — have become this. He leaves her trapped in her own memories, takes over the Apex, and tries to murder her when she returns, even after she saves his life. Simon then has a Cry Laughing breakdown and dies much to the despair of Grace.
• Wham Episode:
  • "The Color Clock Car" ends with Simon killing Tuba, as well as the reveal that Hazel isn't human.
  • "The Hey Ho Whoa Car" reveals that Hazel is one of Amelia's failed attempts to recreate Alrick, and that any car with her in it will be ejected if/when the scanning pulse hits it. Simon also views a tape of Grace's memories and finds out that she purposefully didn't tell him about Hazel's inhuman status.
• What Measure Is a Non-Human?: A theme returning from the previous book. When Tuba is murdered by him, Simon shows no remorse for his actions, whereas Grace is furious when told and later saddened when forced to dwell on it. In addition, when Hazel is revealed to be a denizen herself, it spurs Grace to become more of a protective mother/older sister figure to her. Unfortunately, Grace degrading her to save her own skin a few episodes later makes Hazel feel that Grace doesn't care about her, and thus the turtle girl leaves with Amelia (who doesn't even recognize the girl as anything more than a failed experiment). The finale shows that Grace has fully grown as a person when she sees all the origami birds that Simon stomped on and does her best to heal them. In return, not only do they save her from death via train wheels, but one decides to be her denizen partner.

Book 4: Duet

• The '80s: Takes place in the mid-1980s, based on the bumper sticker on Ryan's van denoting him and Min-Gi as being the "Class of 1985" and the latter noting at one point that the former had been gone on his road trip for almost a year.
• Arc Number: 2. There are 2 new passengers brought in at the same time, they even have the same number: "202", and the title of the season refers to a song that is performed by two people. And although their numbers do go down a few times, they always return back to 202 not too long after.
• Book Ends: The book starts with Ryan and Min-Gi holding a live-show as children in front of their utterly disinterested families. It ends with them playing together at an open mic in Utica, New York as adults, this time to a much warmer reception, with one spectator even asking them for a cassette.
• Buffy Speak: A lot of Kez's dialogue comes across as this, with her attempt to do the usual train explanation leaving Ryan and Min-Gi even more confused about their situation.
  Min-Gi: We're still on a train!?
  Kez: Uh, yeah. Remember? I explained that.
  Ryan: No, you just said we're "in a pocket"!
• Call-Forward:
  • The magnetic boots that the Steward can activate to lock a passenger in place seem to have eventually been discovered by the Apex during Amelia's reign on the train and repurposed into wall-walking footwear.
  • The Denizens' personhood is touched upon again. Morgan, a sentient castle, was largely attached to Jeremy because she has resentment issues from feeling abandoned by passengers that only use her to get their numbers down before leaving forever. Jeremy was her longest passenger, and so far the only one that actually looked after her instead of just demanding assistance.
• Central Theme: Along with the series-wide themes, the season focuses on the effort and communication that's needed to maintain a relationship, as well as facing the fallout of your actions.
• Clingy Costume: When Ryan and Min-Gi wake up in the train, they have magnetic attachments on the soles of their shoes that Kez knows from experience will not come off, which the Steward can use to keep them in place. When Amelia takes control of the train, she has the Steward remove them.
• Dramatic Irony: When learning that a previous passenger once spent up to five years on the train, Ryan is horrified, as he hadn't realized that getting stuck on the train for that long was a possibility. As for the audience, we're well aware by this point that there are several passengers who have spent most of their lives on the train.
• Dramatically Missing the Point: In "The Pig Baby Car", when Ryan learns a lesson and the duo's numbers go down, Min-Gi concludes that Ryan is purely responsible for how their numbers work and that he has nothing to learn from the train. Min-Gi starts being smug and depreciative towards Ryan until the end of the following episode, much to the latter's annoyance, until he learns his own lesson that causes their numbers to drop.
• Easily Forgiven: Played With. In the final episode, Kez finally apologizes for all the trouble she's caused for the angry mob that's been chasing them through the train cars, leading the cow creamer to incredulously ask if she really thought that would solve things... only for everyone sans Judge Morpho to happily accept the apology, saying they'll work out the details of how Kez can make up for the damage she's caused later.
• Evolving Credits: Just like the previous season, the vanity plate changes every episode to fit the car in which Min-Gi and Ryan are in that moment. Their numbers also are visible and static, opposing to Books 1 and 2, and are low enough to be able to keep track of, opposing to Book 3. "The Train to Nowhere" also changes the credits' song to an instrumental version of the homonymous song.
  • "The Twin Tapes", "The Iceberg Car" and "The Astro Queue Car" has Min-Gi and Ryan's numbers stuck at 202, their starting number.
  • "The Old West Car" has their numbers decreased to 180.
  • "The Pig Baby Car" has Ryan's number decreased to 172 and Min-Gi's number back to 202.
  • Starting from "The Party Car" their numbers are down to 127 and they're also using their casual clothes as opposed to the previous episodes where they were using the jumpsuit provided by the train.
  • "The Train to Nowhere" has their hands without any numbers on them, as they exited the train. Min-Gi also has his stylophone in his left hand and its stylus in his right hand. Ryan has his guitar pick in his right hand.
• Foregone Conclusion: As the season progresses, a small side story features Amelia as she gains more control over the functions of the train offscreen: "The Astro Queue Car" has her influencing the Conductor's decisions, as he returns passengers their personal belongings upon her request, and "The Castle Car" reveals that she's now fully usurped the train from One, announcing through the Steward that everyone is on their own now.
• Framing Device: The first episode turns out to be this, with the static and various sudden cuts throughout setting up the reveal at the end that One and Amelia have been watching and discussing Min-Gi and Ryan's processing tape.
• Getting Eaten Is Harmless: Judge Morpho gets eaten by Pig Toddler, but still crawls out of his mouth in the last episode.
• Guilt by Association Gag: Ryan and Min-Gi had nothing to do with the inciting incidents that had many characters throughout the season angry at Kez, and point out as much on several occasions. Each time, they aren't believed or are explicitly told that it doesn't matter, and that they'll share the punishment anyway since they insist on being friends with her.
• Heroic BSoD: Ryan has one in the final two episodes, frustrated that their numbers keep resetting back to 202 and becoming convinced that he and Min-Gi will be stuck on the train for years.
• Lighter and Softer: This season was intentionally written to have a more relaxed and lighthearted tone in comparison to all the prior books, as the writers wanted something that was easygoing after finishing Book 3. As such, there are fewer dramatic moments throughout and a good amount of comedy even in the final episodes. Specifically, there's no Wham Episode featuring a character death or transmogrification, the final confrontation of the season ends in a comedic Anti-Climax, and none of the characters are threatened by Ghoms or any other wasteland threats.
• Meta Twist:
  • The protagonists of Books 2 and 3 were introduced in previous seasons in supporting roles, prior to becoming main characters themselves. Book 4 averts this, as neither of its two leads were featured any of the previous books.
  • Also, this Book differs from the others by not having a single death or a Wham Episode by its final half, unless you count Amelia supposedly taking over the train in "The Castle Car".
• Moose and Maple Syrup: The protagonists of this book, Ryan and Min-Gi are Asian-Canadians (Japanese and Korean, respectively) who grew up in Lake Powell, British Columbia, based on the real-life town of Powell River. Min-Gi works at an expy of a "Humpty's restaurant, one of the songs they sung as kids was about animals wearing toque hats, higher education is referred to as "uni" rather than college, and they make jabs at the bizarre recipes in post-WWII American cookbooks.
• No Longer with Us: When Kez and Morgan first talk about what happened to Jeremy, a previous passenger who was a close friend of theirs, their wording makes Ryan and Min-Gi believe that Kez might have inadvertently gotten him killed. When they decide to get a proper explanation from Kez herself after reading the man's diary, it turns out the "horrible thing" she did that has Morgan incensed with her is... she helped Jeremy finally start working through his trauma, allowing him to get his exit.
• Not Quite Dead: Near the end, a lot of the B-antagonists seem to die, leaving only Pig Toddler... only for Ryan to see the majority of them out the window at nighttime.
• "The Reason You Suck" Speech: Kez gets this from both Ryan and Min-Gi towards the end of the season, pointing out that most of her problems result from her refusal to apologize after making a mistake, and instead running away and downplaying the incident.
• Ship Tease: Aside from the potentially different ways one could see their getting back home together, Min-Gi blushing prominently when Ryan hugs him right before their fall-out could be construed as such.
• Stealth Prequel: Not only does this season take place in the 1980s rather than the present-day, but it also takes place during Amelia's early months on the train. The first episode ends with her discussing the purpose and functions of the train with One-One, who has yet to undergo their personality split and is just simply "One".
• Take That!: "The Pig Baby Car" is filled with potshots against the bizarre and experimental food recipes present in post-WW2 American cookbooks.
• The Unintelligible: The spacesuit bouncer only communicates through the visor changing color. A fellow denizen has to translate for the audience to understand.

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