LeapFrog LeapPad Educational Game: Thomas the Really Useful Engine. BOOK and CARTRIDGE that are only for the Original Leappad learning system, not compatible with the Leappad Explorer Tablet. BOOK and CARTRIDGE that are only for the Original Leappad learning system, not compatible with the Leappad Explorer Tablet. Thomas the Tank Engine is excited to see the children at the train station depot for a school trip Accompany Thomas and see if he can make it through his busy schedule in time to take the children home For 4-6 years