One day, the train on which he was working was visited by AvatarAang, who was undercover at the time, and his friend, Sokka. The two also brought along a little girl named Sho, who would be riding the train to get to her grandmother's house.
Unbeknownst to them, they were being followed by a firebending assassin nicknamed "Combustion Man". With his overdeveloped third eye, he shot a beam of light at the Avatar, causing part of the train to explode. Consequently, the engineer hit his head and passed out, leaving the train without a controller. The conductor attempted to contact him, but to no avail. Sokka then set out to the engine's cab, where the unconscious engineer was located, to slow the train down.
Sokka succeeded in opening the door to the cab after a bit of trouble, but had more difficulty in stopping the train. However, he managed to figure it out and stopped the train, while Aang managed to defeat Combustion Man. The engineer then awoke and discovered that Sokka had saved his train. As an act of gratitude, he gifted Sokka his hat. By the end of this journey, however, his train was rendered unusable.