Captain Toad: Treasure Tracker -- Episode 3-17. Fright Train Flight

Toadette finds herself on the caboose of a train. When you start moving around, a large group of Mud Troopers will appear. Go through the doorway in the car to the other side. Climb up the ladder and you'll find a Chargin' Chuck and the first gem. Lure the Chargin' Chuck off the roof and have him destroy the Mud Troopers. Keep moving and frequently change directions, as it can outrun you on long straightaways. Once all of the Mud Troopers are gone, move forward to the next car with the Chargin' Chuck. The handle on the next car will uncouple the cars. Do so if you like. On this car, there are some bricks between this and the car ahead. There are also some crates. On the other side of them, you'll find a Flaptor, the second gem, and a Mud Trooper. Use the Flaptor to defeat the Mud Trooper. There are other Mud Troopers on this car, some on the other side of the bricks. Use the Chargin' Chuck to break through them and reach the next car, which you can uncouple. This car is flooded with Mud Troopers. Lead the Chargin' Chuck around to defeat them. You can also pick turnips on this car to clear a path for yourself. At the front of the car are two ladders. One is blocked off by bricks. Use the Chargin' Chuck to destroy them. Climb up this ladder for the third gem. The other ladder leads to the handle that will uncouple this car from the engine. Drop down and you'll find more Flaptors and Mud Troopers. Use the Flaptors to defeat the Mud Troopers. Inside the engine room, you'll find Blue Toad with a Mushroom for you. Pull the handle for a 1-up Mushroom. Climb up the ladder to the front of the engine and you'll find another Flaptor and Mud Trooper. Walk around and climb the ladder to the top of the engine, where there are two Flaptors and several Mud Troopers. It will be a little challenging to defeat them, especially as they will crowd the ladder. Lure them to the other side so you can climb the ladder. Once all of them are defeated, drop down the ladder on the other side to the Star.

Special Challenge: Defeat all of the Mud Troopers.