Train (form)

In Super Mario World 2: Yoshi's Island and Yoshi's Island: Super Mario Advance 3, Yoshi can assume a temporary Train form by touching a morph bubble containing its icon. While in this form, Yoshi's snout gains a distinct red color. Trains with Yoshi's visage, similar to his Train form in Yoshi's Island, also appear in other games.

Super Mario World 2: Yoshi's Island / Yoshi's Island: Super Mario Advance 3
This form allows the Yoshis to move along railtracks that are drawn with chalk on walls in the background. While on the ground, the Train can only move from side to side. By standing in front of a railtrack and pressing "up" on the direction pad, the Train will shrink down and attach to the railtrack, whereafter it can start moving along it. The Train can be controlled with the direction pad and sped up by holding the button or the  button on the controller. While moving on rails, Train Bandits, Shy Guy-like enemies apparently painted on the walls, come to life to attack the train, making the player briefly lose control of the train when they touch them.

Mario Kart: Double Dash!!
In Mario Kart: Double Dash!!, the Train appears in the background in Baby Park, at some point going right over the track, damaging any kart that makes contact (except in Time Trials mode).

Mario Super Sluggers
The Train also makes an appearance in Mario Super Sluggers on the Yoshi Park field during the day. It moves along the northern side of the field, stunning any player that it collides with. At night, the Yoshi train is replaced by a Wiggler train.