replacement gears for 4-8153 B&O alco PA loco from around 1981

Yes buy yourself metal worm gears. They fit the late armatures.  Sometime ago one of my Gilbert pa's armature failed. I had some late armatures with the nylon gears. I removed the nylon gears and reused the metal gears from defective armature. The Pa chrome silver flash ran and runs very good. Try it. 

I have a friend who is a tool and die maker. Perhaps I can convince him to do the gear removal and installation. I can't imagine doing it myself without machine tools.

Will the postwar metal worm gear mesh happily with the LIT plastic worm wheel gear?

I think you can find the parts you want on Train Repair Parts or Brasseur electric trains. You can find the blow-up parts diagram on train repair parts.  I believe you can find the worm gear you need. Don't be afraid to take it apart and fix it.

Good luck!

Well? Did to get the parts you needed. Did you get the loco repaired and how. Youn know it's easy to remove the broken worm gear on the armature shaft all you have to do is to slide it off. Well let us know how it goes.

email Chuck and send it to him - it will be back home and running like new.

OK. I emailed Chuck and am awaiting his reply. Thanks for the incentive.