If you have young children like I do (4 kids, aged 5,4,3 and 1) you probably have some Thomas the Tank Engine wooden train tracks. A few of these pieces have this plastic plug that is the “male” piece, which obviously joins with the female piece. Try as you might, there is little that can be done if your bundle of joy pulls out the plug and loses it. You have what I’d call a “neutered” piece. It’s flat, but neither male nor female. Unfortunately, some of the best pieces are usually the ones with this plastic plug male piece in them (hills, splitters, animated sections, etc).
Since this toy is not cheap (for what you get) and I supposedly can fix anything, I had to attempt to figure this out. Searching the internet yielded no results but finally I found a random post on some forum that provided a solution (and the guy who posted it deserves all the credit!)
To help you out, you’ll want to get the right sized eye screws (pic is what I bought at Home Depot), also get the drywall #10 anchors. You’ll end up cutting the anchors (about 1 or 2 ridges should protrude from the hole). When you screw in the eye it doesn’t need to be dead center but try to get it somewhat straight. Electrician’s pliers work very well but honestly any pair of pliers will do fine.
Now I have happy 3 and 5 year old boys. Perhaps your 3 year old son isn’t obsessed with trains like mine, that’s fine, but if he is, I hope this helps.