Leonard Nimoy wasn't originally supposed to appear in this episode as the grand marshal for the monorail's maiden voyage. George Takei (Sulu from the original Star Trek series) was originally picked to appear on the show, but Takei didn't want to appear in something that mocked public transportation (as Takei was on California's Board of Public Transportation at the time and was an advocate of it). William Shatner (Captain Kirk from the original Star Trek series) was also considered, but the idea was scrapped as Shatner already turned down an appearance on a previous Simpsons episode.
The chalkboard gag for this episode is "I will not eat things for money". Bart later does do this in the episode Diggs when he is trying to pay Homer back.
The main premise of a con man getting a town excited about something he sells but hardly knows anything about is borrowed from the musical "The Music Man".
Lanley's appearance and the musical number at the end of the town hall meeting is a nod to some of the songs in "The Music Man" as well.
A "reverse reference" occurred in 2002 when Seattle residents opposed to a proposed monorail project held a protest event called "Coming Out With Marge Simpson". The event organizers planned to show the episode as part of the protest, but were ordered not to by Fox due to copyright laws.
The scene where Mr. Burns (as Mr. Snrub) and Smithers escape the town hall via a grappling hook is a reference to the 1989 movie "Batman". Homer would later mistake Sebastian Cobb, the North Haverbrook contractor, for Batman.
Whilst studying for the monorail conductor exam, the study book is entitled MCAT (Monorail Conductor Aptitude Test), which is a reference to the MCAT (Medical College Admission Test) taken by many medical students.
The sound-alike version of Axel F can be heard in this episode when Mr. Burns takes the toxic waste drums to dispose of.
Snake is shown burgling homes, but is also among the crowd singing the monorail song.
Doctor Hibbert was among the passengers on the monorail on the first ride, but he is seen with a pair of conjoined twins in his office soon after.
After the monorail car is accidentally dropped on the house, a man in the background has legs that aren't colored in.
When Maggie is reaching for the possum in the monorail, her pacifier changes color.
After the monorail song ends, when Homer says "Mono--", Maude's sleeves change from pink to the same color as her waistcoat.