The 'Liftamatic' knuckle couplers are fascinating.
Here's how they work:
1. Preparation: Before coupling, one or both knuckles of the couplers are opened. This prepares them to receive the other coupler. The knuckle rotates on a knuckle pin.
2. Engagement: As the two railroad cars are pushed together, the knuckles of the opposing couplers interlock.
3. Latching: When the knuckles interlock, the movable knuckle rotates, moving past a slot or notch.
4. Locking Pin: A locking pin (or pawl) is in place, and it automatically drops into this slot/notch once the knuckle has rotated past it. This locks the knuckle in the closed position, securing the coupling.
The coupler locking is powered by gravity, no spring trying to push the pin up against gravity like all my Lionel cars and Lionel knockoffs. No spring to fail to hold the pin up like most of my Menards cars.
Speaking of Menards couplers, some have a knuckle shaped like this:
All my Lionel and Lionel knockoff couplers work with the AMT Liftamatic coupler except this particular Menards coupler. The Menards knuckle will not lock with the Liftamatic. You can lock the couplers and put them together by lifting one car and forcing them together, but the train separates for a different reason than a weak spring. The short Menards knuckle works its way past the Liftamatic knuckle, and the train separates.
Here, a Lionel coupler is coupled to the Liftamatic coupler. No problem with couplers locking or with train separation.
