Hardy Menagh   6/28/25

Lionel's operating Automatic Refrigerated Milk Cars, 3462, 3472 and 3482, originally used magnetized milk cans to help keep them upright when pushed onto the platform. Later, the milk car was redesigned and designated 3662. It had a mechanism which operated slightly slower and came with plain aluminum cans. This simplified things and cut production costs. The cans would sometimes still fall over.

There are variations in the size and shape of the magnets in cans manufactured at various times. Most retain their magnetism well but some do not. You should be able to put an 8 D nail under a can and suspend it by the head vertically. It will likely fall off if you turn the can sideways, which is expected.

If you have a can with a magnet that's no longer magnetic, you can pitch it and buy a new one for a couple of bucks or you can restore the magnetism in the old one for free.

The can on the left, in the picture, is an original from the late 1940s. The magnet is small and squarish with rounded edges. These usually hold their magnetism well. On the right is a can whos date and place of manufacture are unknown to me. Notice that the magnet is larger and square. This can had absolutely no magnetism when I got it used. As of now, it will easily suspend a nail.

To remagnetize a can, you only need a strong magnet. The magnet from a loudspeaker is one source. Pictured, is one of the strongest I have. It came from an old hard drive.

Stick the can to the magnet. Slide and nudge the can around to feel for a spot on the magnet where it seems to want to be without resisting. The difference is subtle so don't worry if you can't find a magic spot, just stick it to the magnet. A strong magnet will make the can magnetize quickly but leave it for a day or so. That will assure that the poles in the can's magnet are realigned as well as possible.

I don't recommend sticking a functioning can to a strong magnet. There's no reason to do it and it's possible that you might actually weaken it by misaligning already aligned poles.

If it lost its magnetism once, will it do it again? If so, when? Sorry, I have no data.

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