The best Hobby Train Couplers & Trucks: Reddit reviews

From 3.5 billion Reddit comments

It definitely can be replaced. The term for it is coupler, which may help your search. There are 2 major kinds of ho scale couplers as far as I know. There are the modern kind that are called knuckle couplers that are made by a number of different manufacturers. The kind you have are older and called "horn hook couplers" and I believe you can buy them from a variety of manufacturers as well. From a quick Amazon search I found these. I can't guarantee they'll work but you can do more searching for ho scale Tyco horn hook couplers and see if you can find a pack that look just like the one on the front of your locomotive.

The kadee knuckle coupler on the left is preferred and supports prototype look and operations because the horn on the bottom is metal and by using a magnet you can auto uncouple without having to use “the hand of God” to uncouple.

The numbers of a kadee coupler (also sold by other makers) are cross referenced to height of coupler and length of shaft, and whether truck or body mounted. Some makers provide further info that cross references the number to a specific loco by maker or rolling stock by maker. Once you figure it out, it’s pretty straightforward.

Replacing them can be easy (high quality name brands) or a challenge (copies or clones).

If not sure, a NMRA standard coupler height helps. It’s a plastic block with a coupler mounted on it that you put the rolling stock next to and align the coupler to. Shims can adjust the coupler a little, but sometimes you have to replace w a higher or lower coupler. Alignment ensures no accidental decoupling on curves or inclines. Available on Amazon and well worth the cost.

https://www.amazon.com/HO-RTR-Locomotive-Wheel-Assembly/dp/B001RTG1IS

So, I found this and think it might work to fix the "Hustler"?

Also, when I searched the Athearn Hustler I found things referencing a rubber band drive, not the worm gear drive. You seem knowledgeable, I would love your insight.