Does anyone have a way to adhere the rear drive wheel to the drive gear or replacement drive wheels. The drive gear is on the last set of wheels.

Check with Shapeways. The make a lot of parts for Bachmann trains.

https://www.shapeways.com/marketplace?tag=bachmann 

Rich

Thanks Rich, I'll check them out.

I have a 2nd gen 4-8-4 which is in dire need of repair.  While I can fix most of its problems, the motor front insulating cover has disintegrated so I have no way of mounting it in the split chassis anymore.  It doesn't appear that Bachmann make this motor fitting for split frames as a spare part and I'm not sure that I can get a replacement motor with this insulating/mounting cover.
Anyone have any ideas.
Peter6172, Australia

The answer for engines like this is, as usual, the era of spare parts for Model Railroad engines is long past.  Most of the time you have to buy another model to be a sacrificial animal to get the part you want.  In some cases, you might get one that runs that has a shell you don't care for, so you swap shells to get the road number and name you want.  Then you keep the defective mechanism for parts, minus of course the one that has let go.