History WesternAnimation / InfinityTrain

* AdultFear: Since passengers are gone for real time, every passenger is a case of this, being individuals who have inexplicably disappeared from the face of the Earth with no possible way to trace or make contact with them. Especially distressing since while some stays are relatively short ([[spoiler:Jesse]] is gone for "only" a few weeks), others are stuck there for much longer before leaving ([[spoiler:Tulip]] was gone for at least five months). And then there's the ones who remain on the train for several years, with their families and loved ones likely giving up hope of ever seeing them again.

* BittersweetEnding: [[spoiler: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 significantly down (from 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 (if they're even alive at this point) 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 have pretty much forgotten about them too.]] No wonder the final shot is [[spoiler:Grace giving them all a melancholic and uncertain smile.]]

* BittersweetEnding: [[spoiler: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 significantly down (from 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 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.]] No wonder the final shot is [[spoiler:Grace giving them all a melancholic and uncertain smile.]]

** The damage that lies can do. [[spoiler:The lie that Grace told a young Simon in "The Origami Car" is what would kickstart the entire Apex project. 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.]]

* FamilyUnfriendlyDeath: [[spoiler:If you thought Mace's death was bad, this season is even worse! Simon's death is ''not'' pretty, as his skin graphically melts and his bones are turned to ash right in front of Grace and several of the kids.]]

** The DownerBeginning has a Tragedy Mask [[spoiler: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.]]

** Moreover, [[spoiler: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 left the train sooner]].

* WhatMeasureIsANonHuman: A theme returning from the previous book. [[spoiler: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).]]

* MomentOfWeakness: 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 "[[Recap/InfinityTrainS3E8TheHeyHoWhoaCar 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 angry 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.

* YearInsideHourOutside: Discussed and then notably {{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 [[spoiler: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.

* GoryDiscretionShot:
** Unlike the death of [[spoiler:Mace]] in the previous season, [[spoiler:the death of Tuba]] is not seen, instead having lightning crash to depict it.
** [[spoiler:Averted with Simon's gruesome death at the hands of a Ghom.]]

* DespairEventHorizon: 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.

* MetaTwist: 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, [[spoiler:as mentioned in the previous trope, this Book differs from the others by not having a single death or a WhamEpisode by its final half, unless you count Amelia supposedly taking over the train in "The Castle Car"]].

* ''Book One'' follows the exploits of a teenage girl named Tulip (Creator/AshleyJohnson), 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 LiteralSplitPersonality RobotBuddy named One-One (Jeremy Crutchley and Owen Dennis) and a talking corgi named Atticus (Creator/ErnieHudson). It ran from August 5 to August 9, 2019. ([[https://www.youtube.com/watch?v=atutlhoyc_Q Trailer 1]], [[https://www.youtube.com/watch?v=OYR9pV4f0b8 Trailer 2]], [[https://www.youtube.com/watch?v=bXPZzXeGD6s Trailer 3]])

** In the third season, the aesop is that [[spoiler:"While most people can be redeemed, there are some who, whilst deserving to be redeemed, when given the opportunity won't redeem themselves, simply because they don't want to, and will die before they get to reconsider."]]

** In the third season, the aesop is that "While most people can be redeemed, there are some who, whilst deserving to be redeemed, when given the opportunity won't redeem themselves, simply because they don't want to, and will die before they get to reconsider."]]

** In the end, the biggest lesson of the first season is that [[spoiler:if you let your trauma take over and let yourself want to recreate the past, you never get anywhere. This is the fate that The Conductor/Amelia has to go through]].
** In the third season, the aesop is that "While most people can be redeemed, there are some who whilst deserving to be redeemed, when given the opportunity, won't never redeem themselves, simply because they don't want to and die before they get to reconsider."]]

[[folder:General]]

* VideoGameCrueltyPotential: The flipside to the above, which is touched on in Atticus' 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.

* ''Book Three'' follows Grace (Creator/KirbyHowellBaptiste) and Simon (Creator/KyleMcCarley), 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. ([[https://www.youtube.com/watch?v=5lCscBFY2Lg Trailer]])

* ''Book Three'' follows Grace (Creator/KirbyHowellBaptiste) and Simon (Creator/KyleMcCarley), 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 Delana). It ran from August 13 to August 27, 2020. ([[https://www.youtube.com/watch?v=5lCscBFY2Lg Trailer]])

** [[Recap/InfinityTrainS1E2TheBeachCar "The Beach Car"]] teaches the moral that you should know who your friends are. Tulip selfishly gives One-One away to the Cat after she offered to help Tulip get back home, even though Tulip has no way of knowing if she can trust her. In the end, Tulip realizes that she prefers getting off the train with One-One by her side instead of gambling the chance with his life.
** [[Recap/InfinityTrainS1E5TheCatsCar "The Cat's Car"]] effectively tells the message that one should accept reality as it is and trying to sugarcoat one's memories and/or victimizing themselves leads to a skewed worldview.
** [[Recap/InfinityTrainS1E6TheUnfinishedCar "The Unfinished Car"]] tells a simple moral: "If it ain't broken, don't fix it." One-One feels like it's his responsibility to "fix" the Turtle Car, not realizing that his attempts to change things only irritate them, [[StatusQuoIsGod since they are used to the way things are]]. [[spoiler:Trying to make major changes only causes the near-apocalypse.]]
** In the end, the biggest lesson of the first season is that [[spoiler:if you let your trauma take over and let yourself want to recreate the past, you never get anywhere. This is the fate that The Conductor/Amelia has to go through]]

* AnimatedTattoo: Each passenger is given a glowing tattoo with a number on it that changes based on their behaviour.
* AnotherDimension: 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 [[spoiler:occasionally absorbs passengers who recently hit their number to zero, so they can come off the train and return home.]]

* DeathWorld: 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 a beams of energy that absorb passengers. [[spoiler: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''.]]

* VideoGameCrueltyPotential: The flipside to the above, which is touched on in Atticus' 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.

** Tulip sees someone being sucked up into a vortex in the first episode [[spoiler: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...[[spoiler: from the ''train'', because it's not counting down how long she has to live but how much trauma she's currently going through.]]

** [[spoiler: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 [[spoiler:the vortex is a ''good'' thing, as it means you zeroed out your number and can finally return home.]]

* EverythingsBetterWithDinosaurs: One of the train cars is full of baseball-playing dinosaurs, as seen in [[Recap/InfinityTrainS1E5TheCatsCar "The Cat's Car"]].

*** During the first encounter with the Steward in [[Recap/InfinityTrainS1E3TheCorgiCar "The Corgi Car"]], it flees upon seeing One-One. [[spoiler: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 [[Recap/InfinityTrainS1E5TheCatsCar "The Cat's Car"]]. [[spoiler:She's absolutely correct.]]
** When Tulip [[spoiler:comes dangerously close to crossing the DespairEventHorizon]] at the start of [[Recap/InfinityTrainS1E9ThePastCar "The Past Car"]], her number starts to go back up because [[spoiler: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 [[Recap/InfinityTrainS1E10TheEngine "The Engine"]], where [[spoiler: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''.]]

** When Tulip wakes up in [[Recap/InfinityTrainS1E1TheGridCar "The Grid Car"]], [[spoiler: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 [[Recap/InfinityTrainS1E8TheBallPitCar "The Ball Pit Car"]], [[spoiler: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]].

* FunnyAnimal: The turtle people in [[Recap/InfinityTrainS1E6TheUnfinishedCar "The Unfinished Car"]], though curiously they're led by a quadrupedal tortoise.

* HardTruthAesop: Tulip and [[spoiler: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, [[spoiler: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]].

* LightmareFuel: 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 coloured blocks as they are thrown across the Grid Car.

* LivingMacGuffin: The reason why the [[spoiler: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.]]

* LotusEaterMachine: 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. [[spoiler:[[Recap/InfinityTrainS1E10TheEngine "The Engine"]] reveals dozens of passengers exist on the train simultaneously, but the infinite nature of the train means Tulip never met them.]]

* MoodWhiplash: [[Recap/InfinityTrainS1E8TheBallPitCar "The Ball Pit Car"]] starts off mostly lighthearted as Tulip, One-One, and Atticus play around through a ball pit funhouse, [[spoiler:and then the Conductor shows up...]]

* SamusIsAGirl: In [[Recap/InfinityTrainS1E9ThePastCar "The Past Car"]], [[spoiler:the Conductor is unmasked as Amelia, who deposed the original conductor One-One]].

* ThereIsAnother: It's nonchalantly revealed that Tulip isn't the only passenger in [[Recap/InfinityTrainS1E5TheCatsCar "The Cat's Car"]]. [[spoiler:It turns out the Conductor is one of them.]]

* TrademarkFavoriteFood: Tulip is repeatedly seen eating raw onions, and one of her [[spoiler:altered]] memories in [[Recap/InfinityTrainS1E5TheCatsCar "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.

** In [[Recap/InfinityTrainS1E8TheBallPitCar "The Ball Pit Car"]], the Conductor reveals herself to be the BigBad, [[BreakThemByTalking demoralizing her]] for messing with her "plans", and turning poor Atticus into a Ghom.
** In [[Recap/InfinityTrainS1E9ThePastCar "The Past Car"]], [[spoiler:we learn the truth about the Conductor.]]

** [[Recap/InfinityTrainS1E9ThePastCar "The Past Car"]] has Tulip see the memories of the Conductor, with someone wearing a black hoodie entering the train. [[spoiler: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.]]

* WillReturnCaption: The original television airing of [[Recap/InfinityTrainS1E10TheEngine "The Engine"]] had a [[https://www.youtube.com/watch?v=lJg3RGhZxzw short promo clip]] air before the credits sequence, telling the audience this.

* BreakThemByTalking: In "The Wasteland", [[spoiler: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 [[NiceJobFixingItVillain another idea to try out]].]]

* ChekhovsSkill: Alan Dracula's EyeBeams and [[RunningGag constant craving for grass]] end up helping MT and Jesse [[spoiler: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.]]

* DoubleMeaningTitle: The name ‘Cracked Reflection’ applies to both MT and Jesse. MT is essentially "cracked" because she [[TakeAThirdOption 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.

* InternalDeconstruction: 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 [[WhatMeasureIsANonhuman experience extreme brutality at human hands.]]

* MeaningfulRename: MT chooses to rename herself [[spoiler:"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 LineOfSightName, as she chooses the name after staring into a nearby one.]]

* WantedPoster: 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.

** Simon's experiences in "Le Chat Chalet Car" further fire his desire to [[spoiler: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 [[OOCIsSeriousBusiness panics]], thinking its real. [[spoiler: At the end of the season, a Ghom kills him.]]
* ForWantOfANail: All over the place. For example [[spoiler: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, [[spoiler: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 left the train sooner.]]

* MomentOfWeakness: 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 episode [[Recap/InfinityTrainS3E8TheHeyHoWhoaCar 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 angry 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.
* MutuallyUnequalRelation: {{Exploited|Trope}}. In the first episode of Season 3 [[Recap/InfinityTrainS3E1TheMusicalCar 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.
* PoorCommunicationKills: Much of the drama with [[spoiler: Simon]] happens from either others telling him information or him misunderstanding what other people want. Most Notably if [[spoiler: Grace]] had told him not to kill [[spoiler:Tuba]] period, or [[spoiler:Simon]] had understood [[spoiler:Tuba]] wasn’t going to abandon Hazel like Samantha did him, much suffering could’ve been avoided.
** The Cat does this literally to Simon; [[spoiler: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.]]
* PsychopathicManChild: 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 [[RapePillageAndBurn 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.
* ProtagonistJourneyToVillain: Downplayed with Simon, who was already a VillainProtagonist from the start, but like Grace, has some redeeming qualities and sympathetic traits shown during the first half of the season. [[spoiler:But a combination of being reminded of his [[TraumaButton Traumas]] and his paranoia getting the better of him leads him to double down on his pre-existing hangups and [[NeverBeHurtAgain hurt Grace under the delusion that she was going to abandon him]]. , The second half sees him undergoing more SanitySlippage and becoming worse and worse, until he eventually takes up the mantle as the BigBad of the season and tries to kill Grace, his ChildhoodFriend and then have a mentally breakdown shortly before being consumed by his lifetime trauma.]]

** The climax of Episode 10 contains one for [[spoiler: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.]]

* RewatchBonus: Upon first watch, viewers might notice that Hazel talks with distinctly british phrasing despite not having an accent. [[spoiler: This is likely due to her status as an imperfect clone of Alrick.]]

* ShipTease: Grace and Simon mix with this with ChildhoodFriendRomance. 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 DanceOfRomance. 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 FirstKiss with each other. [[spoiler:Simon’s sanity slippage and death means this goes nowhere.]]

** By the end of the season, [[spoiler:Grace and Simon -- best Childhoodfriends, 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 CryLaughing breakdown and dies much to the despair of Grace]].

* WhatMeasureIsANonHuman: A theme returning from the previous book. [[spoiler:When Tuba is murdered by Simon, 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).]]

* CentralTheme: Along with the series-wide themes, the season focuses on the effort and communication that's needed to maintain a relationship, as well as [[spoiler:facing the fallout of your actions.]]
* ClingyCostume: 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. [[spoiler:When Amelia takes control of the train, she has the Steward remove them]].

* DramaticallyMissingThePoint: 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 deprecative 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.

** "The Pig Baby Car" [[spoiler: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 [[spoiler:using their casual clothes as opposed to the previous episodes where they were using the jumpsuit provided by the train.]]
** "The Train to Nowhere" [[spoiler: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.]]
* ForegoneConclusion: As the season progresses, a small side story [[spoiler: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.]]

** Also, [[spoiler:as mentioned in the previous trope, this Book differs from the others by not having a single death or a WhamEpisode by its final half, unless you count Amelia supposedly taking over the train in "The Castle Car".]]

* AndroclesLion: At the beginning of Episode 10, [[spoiler: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, [[spoiler:those same origami denizens are the reason Grace survives the season; Simon kicks Grace off the train to be wheeled, but Grace survives because the origami birds grab her and fly her back up to the train.]]
* AnyoneCanDie: And how. By the end of the season, [[spoiler: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.]]

* BaitTheDog: 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 [[spoiler: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, [[ObliviouslyEvil Obliviously talking about killing her adoptive mother to]] Hazel, and it's all downhill for the remainder of the season.]]

* FalseCameraEffects: The show utilizes slight film grain and distortion effects to replicate the feeling of watching an older television show. A handful of episodes also make use of RackFocus.

* RewatchBonus: Upon first watch, viewers might notice that Hazel talks with distinctly british phrasing despite not having an accent. [[spoiler: This is likely due to her status as an imperfect clone of Alrick, who is British.]]

--> "He's a good sort, but [[CloudcuckooLander barking mad."

* BittersweetEnding: [[spoiler: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 significantly down (from 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 her fault, and she and these kids will return home to a family who may or not remember them and a world that they must adapt with little to no resources and education at the ready.]] No wonder the final shot is [[spoiler:Grace giving everyone a melancholic smile.]]

* BittersweetEnding: [[spoiler: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 significantly down (from 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.]] No wonder the final shot is [[spoiler:Grace giving everyone a melancholic smile.]]

* RayOfHopeEnding: [[spoiler:While Simon is dead, Grace decided to reform the Apex. 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 climax of Episode 10 contains one for [[spoiler:Simon, as Grace tells him that while he's in a lot of pain and Grace can see that, Grace is not responsible for all his problems.]]

%%* Reality Ensues: MT and Jesse form a strong friendship over the season, each learning to accept the other's flaws and help them deal with it. He even promises to help her leave the train when he does. [[spoiler:When Jesse zeroes out and is forced to leave the train in "The Mall Car", he's traumatized over being unable to keep his promise and leaving her at the mercy of the Mirror Police. So traumatized, in fact, that the train picks him up again.]]

%%* RealityEnsues: MT and Jesse form a strong friendship over the season, each learning to accept the other's flaws and help them deal with it. He even promises to help her leave the train when he does. [[spoiler:When Jesse zeroes out and is forced to leave the train in "The Mall Car", he's traumatized over being unable to keep his promise and leaving her at the mercy of the Mirror Police. So traumatized, in fact, that the train picks him up again.]]

* SomeAnvilsNeedToBeDropped:
** [[Recap/InfinityTrainS1E2TheBeachCar "The Beach Car"]] drops the anvil that you should know who your friends are. Tulip selfishly gives One-One away to the Cat after she offered to help Tulip get back home, even though Tulip has no way of knowing if she can trust her. In the end, Tulip realizes that she prefers getting off the train with One-One by her side instead of gambling the chance with his life.

* NotSoDifferent: After watching [[spoiler:Amelia]]'s tape, Tulip is at first angry because she didn't want to feel bad for [[spoiler:her]], preferring to think of [[spoiler:The Conductor]] as "some heartless robot thing", but now she realizes that [[spoiler: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 [[spoiler:brings Tulip's number all the way down to 0 and opens her exit car containing the portal that will take her back home]].