I have train my dad got me when i was born and it doesnt work correctly.  The motor runs but makes a very bad clicking noise when it runs.  I took the wheels off so it was just the three little drive gears attached and it made the noise.  When i take the gears out so its the motor by itself it sounds great.  I want to replace the drive gears but all i can find is a gearbox version.  Mine just have the three gears pinned right through the side of the train frame.  Anyone know where i can find these?  The train is a model # 90015 G scale big hauler from 1990