From the Super Mario Wiki
The Toad Conductor is a Toad that appears in Paper Mario: Color Splash. He is the conductor of the Sunset Express. He wears overalls over a light blue shirt, and he has some spots of oil or dust on him.
When the Sunset Express arrives at Kiwano Temple, the Toad Conductor can be found standing with the leader of the Blue Rescue Squad in front of the area of the track Mario had destroyed when he first went to Kiwano Temple. The Toad Conductor will yell at Mario, and then he will tell him that he is mad that someone broke the tracks. When Mario finds all of the members of the Blue Rescue Squad and they use their bodies as a substitute for the track, the Toad Conductor happily gets into the Sunset Express. After moving along the track a little bit, he and the train are crushed by a Big Thwomp. He tells the passengers to push the train to the Toad Trainworks.
At Toad Trainworks, the Toad Conductor can be found near the orange Mini Paint Star. If Mario speaks to him, he says that he doubts the Sunset Express will ever run again.
When the Sunset Express reaches Tangerino Grill after being repaired, the Toad Conductor will thank Mario for helping him reach their destination.
When the Sunset Express is hijacked by Larry Koopa, the Toad Conductor rides with Mario on a handcar to reach the train. During the Larry Koopa battle, the Toad Conductor helps Mario by stopping the Shy Guy that heals Larry by placing Hearts into the fire chamber on the train. Mario must defeat three waves of enemies so that the Toad Conductor can safely reach the cabin. If Mario does not defeat every enemy in one turn, they will attack the Toad Conductor and knock him back. If Mario uses a POW Block, the Toad Conductor will become crumpled, causing him to be unable to move for a turn. When he reaches the cabin, he will chase the Shy Guy off the train and take control of it.
When the train arrives at Starlight Cape, the Toad Conductor can be seen talking to a blue Toad. They decide that the Sunset Express should not be decommissioned.