Barrel Train

The Barrel Train is Diddy Kong's unlockable kart in Mario Kart: Double Dash!!. It is a lightweight kart, but like Bowser Jr.'s kart, the Bullet Blaster, it has greater speed, but less acceleration than most other light karts. It is unlocked by completing the Star Cup in 150cc. Its nitrous comes from the horn, which makes the sound of a train whistle when speed boosting. Like any steam train, its exhaust pipe is a smokestack.

The Barrel Train is the heaviest lightweight kart in the game (weight is tied with the Red Fire and Heart Coach), and the fastest (tied speed-wise with the Bullet Blaster), but has the lowest acceleration among all lightweight karts.

His train can be seen in Mario & Luigi: Partners in Time buried in Gritzy Desert. However, it may just be a coincidence, that this train looks a lot like the Barrel Train. Another train named the "Barrel Train" appears in Mario Party 8. However, it is not the same train, as it is a full-size locomotive. Later in Super Smash Bros. Brawl, it appears as a sticker that raises a player's attack by nineteen.

Trivia

 * The Barrel Train is the only lightweight kart capable of pushing around certain karts from the medium weight class. They include the Green Fire and Bloom Coach.