I will show you how to make a rocket sled on train wheels.

Step 1: Step 1. Train Tracks

Step 1: Rails. In order to make the rails, you need a cube and make it into a thin rectangle. You want to make about 20 more of these and have them in a straight line as seen in the picture. Then, you want to make two long rectangles and put each rectangle on top of the rectangles. One on the left and on the right. Next, you want to make two long and thin rectangles that are vertical and put that on top of the rectangle. Now, the train tracks are done.

Step 2: Step 2. Wheels

s For the train wheels, you want to make four big wheels and four smaller wheels that will be attached to the bigger wheels. Then, you want to make two tubes that will be for the two wheel sets. The tubes will go in the middle of the wheels. After that, make sure the small wheel is on the thin, vertical rectangle as seen in the picture. The wheels are now done.

Step 3: Step 3. Body (Front)

For the front, you want to make a circle that will be diagonal to the right and then have a cylinder for the circle that will be in the cylinder. Now, you want to make one more circle that will go in the back of the cylinder.Then, attach that to the wheels and your done for the front part.

Step 4: Step 4. Back Part

To begin, you want to make two long rectangles and put them on the bottom and right next to to the the cylinder with the circle diagonal to the right. Then, you want to make two more rectangles shorter and diagonal to the back. Next, make two straight rectangles and put that on top of the rectangle that is diagonal. Now, you want to make one square with four holes in it for the rockets to in it. The square will go in the right behind the rectangle that is diagonal to the right. Now, to make the rockets, you want a cylinder and one half sphere. Make the half sphere the size of the cylinder and now you need another half sphere. For this half sphere, make it a little bigger and make a hole on the bottom in the middle. Then, you can attach all the parts and make three more. Finally, put the rocket where one of the holes are and do this with the other three. Then, you want to make four cylinders, a size that will fit in the rocket and four spheres that will be attached to the small cylinders. Then, put the cylinders with the spheres into the rockets with some of the cylinder sticking out of the rocket. The sphere should also be on the outside of the rocket. Now attach all the parts to move it onto the tracks.