If the screw is stripped, I assume you managed to put batteries in before it happened (but made a wrong move, applied too much force or used an incorrect screwdriver when tightening). Have you tried using one of the other two controllers to see if he responds? If not, try cleaning the transmitter LEDs on the side of the controller. Since it's a HiT Toys Thomas and there are no "security" (triangle) screws, you could try disassembling him to check the wiring. There's a receiver in front of the drive unit that's wired to the battery van, motor and a low battery light. If there are any snapped wires, I hope you have soldering equipment.
Side note: you might be confusing it with the Hero of the Rails Talking Thomas, which is also Flip Face (but not RC) and has the same cross face the one in your avatar has (albeit with simulated coal dust).
Side note: you might be confusing it with the Hero of the Rails Talking Thomas, which is also Flip Face (but not RC) and has the same cross face the one in your avatar has (albeit with simulated coal dust).