- Alternative Character Interpretation: The scene where Naphi tries to follow Mocker-Jack down a sinkhole. Many people see it as simply a sign of her insanity, believing she could kill a giant mole—that is currently on fire—with a knife. However, if you think about it, it isn't entirely unlikely that the captain was knowingly trying to off herself; after all, she was pretty obviously derailed by the mutiny earlier, & now she's just watched her philosophy get murdered by something that was not her.
- Did You Think I Can't Feel?: Impliedly, Sirocco near the end. Despite acting very "cool" throughout all of her screentime, after seeing how heartbroken Sham is over the fact that she had only come with him for the potential valuable salvage, she rigs a dead angel and goes after Sham and his group—though still continues to claim that it was not her idea.
"Iíve heard of this place, as have you. & it is true that when Mr. Mbenday said the switches were misbehaving, a possibility occurred to me. So if you arraign me before your court accused of having halfheld notions, fleeting recollections, then I plead guilty. If, however, you claim I deliberately allowed my crew to steer themselves into danger, then sir how dare you?"
- To a more obvious extent, the captain; depite doing a fairly great job of being The Stoic throughout most of the book, in the first (failed) mutiny after the fight with the siller, she makes it very clear how hurtful the constant accusations of not having any sort of human feelings are.
- Does This Remind You of Anything?: At one point, Caldera talks about the "trainsfolk down south" that get regularly labelled as pirates, while all they want is to protect their coasts from waste-dumping corporate trains.
- Vague Age: Most of the characters. It gets more confusing once you realize that average lifespan could be completely different thousands of years in the future, when Railsea takes place; some of the characters whose age isn't specified could very well be several centuries old.
- Shoot the Shaggy Dog: Naphi's character arc. Subverted in that she doesn't die, though arguably her ultimate fate is even worse.