Minecraft wiki entry for Minecart_booster, associated text: Possibly the simplest booster (recommended for long, level tracks) only requires a single track and three minecarts. Line the carts up on the track and push the rear one into the other two repeatedly, and at least two of the carts will lock together and boost each other continuously until they reach their destination. This is a bug that seems to have to do with the carts hitting each other, so this may take a few attempts. As such, it's recommended to make the rear cart a Powered Minecart and start it with a few coal, then jump in the front cart so you don't get left behind. The powered cart will knock into the other two until the bug kicks in.