A level set in a mountainous region with a heavy presence of trains and train tracks. The freightliner trains in the levels are similar to those found across the United States and Canada. This level has an appearance similar to a mine, with scenery such as mine carts around the level, and has electric wires above the train tracks that Sonic can rail grind on. It is distinguished from other levels featuring trains in games such as Sonic Adventure and Sonic Heroes in that it has a highly realistic appearance with trains modeled off of real-life railroad equipment. Radical Train also is homage to Quartz Quadrant on "Sonic CD"
This is also the only stage in the game that all three hedgehogs play through at the same time.
- Sonic's Story (6th Stage)
- After escaping from the future, Sonic and the others try to search for Princess Elise once again.
- Boss: Egg Genesis
- Shadow's Story (6th Stage)
- Shadow wants answers about Mephiles, so he decides to destroy Doctor Eggman's train in order to stop him and ask him why he is also trying to capture Mephiles.
- Boss: Silver
- Silver's Story (6th Stage)
- Along with Blaze, Silver continues his search for Sonic through this stage, but, upon finding Sonic, Shadow gets in the way, and Silver mistakes him for Mephiles.
- Boss: Shadow