There are four small screws underneath the locomotive that will allow you to remove the fuel tank and battery boxes.
Once the fuel tank is off, you will see the screws that release the cab. The cab will slide straight up and off of the hoods, with the interior remaining behind on the frame. (You can remove the smaller screws to release the interior from the frame if you wish.)
Once the cab is removed, the large screws at the ends of the hoods will allow you to remove them.... after that you can remove the circuit boards and trucks ... depending on how far you're stripping it down.