The Bullet Bill Express

The Bullet Bill Express, or, is the third castle level of Super Mario 3D World and the eighth course in World 3. It is unlocked via completing Switchboard Falls, and its own completion frees the Blue Sprixie Princess who builds a Clear Pipe to A Banquet with Hisstocrat. This level autoscrolls.

Layout
The level starts on a platform with some Question Blocks nearby. The player must hop on the nearby train and avoid some nearby Flopters, Cat Bullet Bills, and a Goomba Tower in order to reach a secret block containing a Mega Mushroom. Cat Banzai Bills now start to spawn from the parallel train, and can be used to destroy some nearby Crates. Two Fire Bros. appear soon after followed by a nearby pipe which leads to the boss of the level, Pom Pom. After the player defeats Pom Pom, a nearby Warp Box transports them to an area with a + Clock, the Goal Pole, and the Sprixie Princess.

Green Stars

 * Green Star 1: Seen at the very beginning, the first green star is on the edge of the caboose.
 * Green Star 2: The second green star is held captive by a Goomba Tower.
 * Green Star 3: There's a Warp Pipe on a flatbed railcar that takes the player to the other train where Captain Toad is trapped inside a crate. When freed, Captain Toad will reward the player the green star.

Stamp

 * It is guarded by a Fire Bro. inside the train.

Enemies

 * Bullet Bills
 * Flopters
 * Cat Bullet Bills
 * Cat Banzai Bills
 * Goomba Towers
 * Fire Bros.