Lionel 3451 Log dump car

You are making a very good observation.

Actually, only one coupler opens when the car is unloaded. "Uncouple" fires both couplers.

This is a carry-over of the prewar versions that operated the same way and were identical electrically.  The big difference is that the prewar couplers "re-closed" when the unload button was released... as they were operated(closed) by gravity. The train stayed together.

Which leads up to the early postwar development and eventual 1948 beginning of the roll-out of the magnetic coupler system still used today. The new system had to be completely compatible / reverse-compatible electrically with those prewar operating cars and all knuckle-couplered cars that had been built since 1945.

Thanks guys for starting this discussion I too wondered how and why.....cheers...joe

Disconnecting the coupler will not be easy. The power to the coupler is through a brass spring that also applies the spring force to the sliding shoe. The magnet wire from the coupler coil is wrapped around a hole in a hard fiber board that the spring also snaps into.   The magnet wire from the coupler could be cut, but the might not leave enough wire to ever restore it. 

A reasonable modification to correct this issue would be to change the electromagnetic coupler trucks to magnetic tab coupler trucks.   The type TC trucks could be changed to the 482 trucks. Or just the bottom plate could be changed to the 482-3.  A lot of these 482-3 bottom plates are around as this was a common modification. 

This modification would essentially converted the 3451 log car to a 3461 log car. 

It isn't that big of a deal as with the 3 position E-unit, one would cycle in the opposite direction re-closing the knuckle before moving forward.

You can read more about the wiring in this post: https://ogrforum.com/...-lionel-3451-log-car

bmoran4 posted:

It isn't that big of a deal as with the 3 position E-unit, one would cycle in the opposite direction re-closing the knuckle before moving forward...

 

If you are able to access videos from the "1949" showroom layout, this is exactly what was done for demonstration.