Yes, there are several Hidden Mickeys on the Seven Dwarfs Mine Train in Magic Kingdom. The most famous one is found toward the end of the ride within the mine cavern; as your train slows down and passes the animatronic Seven Dwarfs working, look to the right of Grumpy (who is near the end of the scene). On the wall behind him, there are three purple gems arranged in the distinct shape of a classic Mickey head. Another well-known Mickey is "carved" into the wooden beams of the loading station; if you are standing in the front rows of the boarding area, look up and across the tracks at the horizontal support logs to find a Mickey silhouette etched into the wood. There is also a Mickey made of three spilled jewels on the floor near the "shadow" projection of the Dwarfs walking home. These subtle tributes are part of a long-standing Disney tradition, rewarding eagle-eyed guests for their attention to the intricate details of the attraction's "Storybook Circus" and "Enchanted Forest" surroundings.