I have a older bachmann spectrum K4 that stopped moving forward or reverse. It is a non DCC engine. I have power to the light. It is a split frame engine. I removed the boiler . I am thinking a gear cracked. I removed the screws on the bottom plate hoping I could see something. The plate will not come off. Any suggestions on how to proceed? I have the diagram from HOseeker but do not know where to go next.Thank you in advance.