The monorail is an immense mass transit network spanning the entire city of Ba Sing Se that serves as the primary mode of transportation for the city's aristocracy and general population. Originally, the cars were pushed from one end of the rail network to the other by a group of earthbenders. By 171 AG, the cars became powered by mechanical engines. Zaofu also has its own mechanical engine monorail system, connecting the different metal lotus portions of the city.
The monorail was the brainchild of Earth King Yi Ming, an ingenious but impatient ruler who was tired of having to spend two full days traveling from one end of his city to the other. He tasked his engineers with finding a solution to his traveling woes; the result was the best mass-transit system in the entire world, with no equal in speed, safety, or comfort.
Years later, this mode of transport remained in heavy use by commoners to traverse the city. To use the monorail, people needed to acquire a ticket. When Iroh and Zuko had traveled to the capital as refugees, the ticket woman was skeptical of the passports they had presented for Mushi and Lee respectively. In order to get the needed tickets, Iroh flattered the lady with sweet talk, and she subsequently stamped the passports without a second thought. On the monorail, they encountered Than, Ying, their newly-born daughter, Hope, and Than's sister. Other known travelers on that same train ride were Jet, Smellerbee, and Longshot, the former members of Freedom Fighters.
When Team Avatar made it to the city after losing Appa to the sandbenders in the Si Wong Desert, they used the monorail as well. On this train, they encountered a strange man sucking on a corn cob.
In 171 AG, Mako and Bolin pursued a runaway Kai, who ran into a monorail car. Despite having grabbed him on the collar, the young boy escaped Mako by using airbending, leaving the car just before the doors closed. The two brothers were transported to the Lower Ring, where they tried to board a monorail back to the Upper Ring, though were denied access after they could not pay for their tickets or show their passports, having been robbed by Kai.
Each train is powered by two earthbenders standing at the end of the vehicle, pushing it along the tracks. Inside, there are benches provided for easy travel comfort, as well as overhanging bars that travelers can hold on to when there is no room to sit down. The schematics of the monorail show that the windows of the train are covered with paper to hold the wind out, but can also be opened to allow people to look outside.
Major technological advancements over the next seventy years changed the monorail cars in design, particularly in that the paper windows were replaced by glass topped with intricate metal finishing. In addition, the exterior of the car was painted to be entirely green and an announcement system was added both in stations as well as inside of individual cars to announce destination points and upcoming stops. Mechanical engines have replaced the earthbenders who previously powered the cars and doors have become automated and lock securely during operation.
- ↑ 1.0 1.1 1.2 Hedrick, Tim (writer) & MacMullan, Lauren (director). (September 22, 2006). "City of Walls and Secrets". Avatar: The Last Airbender. Season 2. Episode 14. Nickelodeon.
- ↑ 2.0 2.1 2.2 Hedrick, Tim (writer) & Graham, Ian. (June 27, 2014). "The Earth Queen". The Legend of Korra. Season 2. Episode 3. Nickelodeon.
- ↑ 3.0 3.1 DiMartino, Michael Dante (writer) & Heck, Colin (director). (July 11, 2014). "The Metal Clan". The Legend of Korra. Season 2. Episode 5. Nickelodeon.
- ↑ From older Avatar: The Last Airbender official site, originally on Nick.com (link). No longer updated.
- ↑ DiMartino, Michael Dante, Konietzko, Bryan (writers) & Volpe, Giancarlo (director). (September 15, 2006). "The Drill". Avatar: The Last Airbender. Season 2. Episode 13. Nickelodeon.