Janet's Magic Omnibus

   The Bus   "The Bus" (a.k.a. The Magic School Bus, "Bus" by Valerie and Fiona, and "Bussy" by William) is the common name of the anthropomorphic school bus that Ms. Frizzle's class and Liz ride on and goes on field trips and is the main character in the series. It is most often piloted by Ms. Frizzle, her sister Ms. Frizzle or Liz, but occasionally, one of the kids will take the wheel (like Ralphie in "Kicks Up a Storm" "Going Batty" and "Gets Lost in Space", Wanda in "Gets Lost in Space", Carlos in "Gets Ready, Set, Dough", and Tim and Phoebe in "Taking Flight") or it will take on a shape (such as an animal) that allows it to "drive" itself.
 * Model Type: 1970s Ward International R-183
 * Manufacturer: Ward International Trucks, Inc.
 * Owner: Ms. Frizzle

Basis
The Autobus is somewhat based on a Bluebird TC/2000 bus with fender skirts on the rear wheel, the front windshield being 2 different windows, and a grille spine down the center of the hood.

Internal mechanics
It isn't really clear how The Magic Omnibus works, but there are some hints in the TV series. We can see the how the fuel gets to the engine in The Dud13 Movie: The Prequel. First of all, its magic seems to flow from several unusually named devices, like the Shrinker Scope or the Mesmerglober. The Shrinker Scope serves mostly as an easy way to shrink and resize its target at the will of Ms. McDanny. It seems to have at least two varieties of the Shrinkerscope, namely, the main one (as an internal part) and the PortaShrinker. At least the latter can't work when damp or wet, and if someone attempts to activate it in such conditions, the Dew Dinger sounds (the dew dinger is the EAS warning beep but its a square wave instead of a sine wave that plays from a Tweeter Speaker hidden in the dashboard).

The Mesmerglober, on the other hand, is primarily concerned with changing the shape of a person. It changes a random object into whatever Janet needs, be it a submarine, a spaceship, or a alligator.

In the prequel for the Dud13 Movie, it pretty much reveals where the Autobus's "Magic" comes from: a Magic Battery (Mag-Batt for short) and it stores it's energy in a special glittery soup (that is not edible) the magic also comes from the time core under the hood.

Trivia

 * The bus was able to float around in lava this may lead to that the bus may be physically indestructible, but it isn't, it uses an invisible shield to prevent it from getting damaged in mild conditions.


 * The Magic Omnibus is revealed to have a district name written on the sides This is further shown in the scene where Janet started to paint it after she had done work on the frame and body.
 * The bus also has a Detroit Diesel Series 71 engine replica. This is further shown when it felt exhausted upon Janet overloading it with engine power when trying to get it up to 255 mph (the speed where this bus usually starts to time travel). It is shown The Bus is incapable of going over it's max speed, but it is capable of "sneezing" loud enough to scare anybody every time the parking brake is engaged.