- Creator's Favorite Episode: Conan O'Brien has said that of all the episodes, this is his favorite.
- Cross-Dressing Voices: The cackling old lady in North Haverbrook is voiced by Dan Castellaneta. As a result, her voice bears an uncanny resemblance to Itchy the Mouse.
- Deleted Scene: A scene that was cut for time had Lisa reading a children's book about monorails, written by Lyle Langley, to Maggie.
- Magnum Opus Dissonance: Despite it often being considered one of, if not the best episode of the series (second only to "Last Exit to Springfield"), Yeardley Smith has been vocal in her dislike of the episode. In a 1995 interview, she heavily criticized it for not fitting in well with the show's then-usual style.
- Orphaned Reference: Homer's sci-fi inspired conductor outfit was designed in response to a joke that was cut from the episode:Homer: Well, how do I look?
Selma: Like Darth Vader without the helmet. - The Other Darrin: This is the only time in the series Lurleen Lumpkin is voiced by someone other than Beverly D'Angelo. For her brief appearance here, Doris Grau provides the voice (though it's justified here, as Lurleen Lumpkin has had a hard life after Homer sold her to another manager to save his marriage).
- What Could Have Been: The writers actually wanted George Takei to voice himself in this episode, but Takei refused to be on anything that satirized public transportation, as he's an advocate of it.note The writers then turned to William Shatner, but he turned them down before to appear on the show, and feared he'd do the same this time around. Then they asked Leonard Nimoy, he said yes, and the rest is history...
General Trivia
- By incredible coincidence, Leonard Nimoy's name is an anagram of "Deny Monorail".
- It was the runner-up
in Splitsider's 2012 poll of best sitcom episodes ever, but lost by a surprisingly wide margin to the Community episode "Remedial Chaos Theory". - Matt Groening's favorite lines from this episode are "I call the big one 'Bitey'" and "Donuts. Is there anything they can't do?".
