@trainbob posted:Thanks everyone for their help and for those that don’t know there is only one Lionel Aquarium
Hope your gear fits and works Bob. Just so others aren't thrown off by your last comment there are in fact multiple (over 2 dozen) aquarium cars by Lionel with at least 3 different screen operating configurations. Those include:
1 -Large motor and gear as shown in your pics above.
2 Mechanically driven off the truck/wheelset.
3. Miniature motor with brass worm gear and gearbox (pic below).
Steve's idea to flip the worm gear looks like it would certainly work based on the wear pattern if your replacement gear is incorrect.