Tank train



The tank train is a hybrid Fire Nation war vehicle, combining a land train and an armored tank. It is primarily used as a means of transportation, as it has been designed to travel at high speeds over most terrain, and is capable of hauling many people and large loads of cargo across great distances.

History
Azula, Ty Lee, and Mai used this fast-moving vehicle to track Aang and his friends all over the Earth Kingdom. Every time the team laid down to rest, Toph sensed the machine's approach, stating that it felt "like an avalanche, but also not like an avalanche". The team fled from the unknown approaching danger all night, physically and mentally draining themselves from lack of sleep.

With Appa utterly exhausted, they decided to face the machine and found out that it was Azula, Ty Lee, and Mai who were tracking them down. The three girls emerged from the tank on mongoose dragons and charged the foursome. After seeing that the three girls avoided their defensive attacks with ease, Team Avatar decided to flee.

After Toph discovered that it was Appa's shedding fur that left a track for the three girls to follow them, the team gave the sky bison a bath. Aang used some of Appa's fur to lead the Fire Nation girls off their trail while Katara and Sokka flew away on Appa. Unfortunately for the group, the still tired Appa knocked off some treetops on his ascent, which was noticed by Azula. The girls then ditched the tank train in favor of three mongoose dragons, which were also kept in the tank train. Azula followed Aang's trail while Mai and Ty Lee pursued Appa.

Design
By using the concept of their tanks and building upon it, the Fire Nation was able to make a vehicle powerful enough to go virtually anywhere and large enough to transport people as well as weapons. It can often be spotted from miles away because of the plumes of smoke and steam bellowing from its engines.

The tank train is the size of a regular train and consists of several cars. The first car is the work-horse, which houses the engine. The vehicle runs on firebending and coal. This first car also has a functional design; the sharp, armored plow on the front is used to batter a path through obstacles, and it prevents large objects from getting underneath the train and damaging the undercarriage. There are also two huge grappling hook cannons on either side of the car. The next two cars, which can be added and removed as needed, are for hauling things.