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Tower Operator
Long story short; the 'trip pin' of the lead car doesn't appear to be opening up when coupled to the 2nd car at the crest of the hump. Separately that trip pin does open when not coupled, but together it doesn't appear to be moving. thou it's hard to tell. One does, the other doesn't.

I've move the uncoupling magnet 'up' closer to the crest, but that hasn't changed anything.

Now if I push the string of cars with my hand the cars usually uncouple by the 'jerkiness' of my hand (for lack of a better term).

The uncoupling magnet is 1/2" from the crest. Lastly, I believe I made the crest to 'broad' making matters worse. But that is reaching for a reason this isn't working. See the attachments.

Hope all of that made sense.


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Well-Known Member
Wish I could help. I've not yet contemplated a decoupling magnet anywhere, but mostly because I'm completely ignorant of how to use them effectively, especially in N gauge.


Well-Known Member
Try adding another ramp (two of them) right next to the other one to the left, giving a longer area of magnetic action so they will uncouple on the approach side, buff forces and be held open to the crest.

Now you know why model hump yards aren't that common, they are very difficult to make work well.


Well-Known Member
I was aware that humps are not common which id why I wanted one.
I built a hump yard for the same reason. Found out that the smooth rolling expensive rolling stock acted markedly different from the squeaky wheeled older rolling stock that I started out with.

Turned out my hump yard videos were my most popular. Over the couple years that I ran that layout, the hump yard got pretty good. The things I learned were to have a fairly level area with the uncoupler, with a slight decline where the leading trucks of the car to detach was. I buried some grass stems in the middle of the tracks to slow down the cars. This was HO scale so speed was at times a factor.

If I were to give any advice about the yard, it would be to use the wired uncoupler with the big magnet that turns off and on. This is HO scale so I am not sure about N scale.


Active Member
Another Pos. 'approach':
Try putting ramp, instead, at bottom, before hump; knucks opening there, then pushing cars up and over the crest, the delayed-action keeping couplers open up hill, allowing car/s to coast down other side of hump.
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Tower Operator
I moved the magnet up again another 1/2 to 3/4 inch just past the crest and it improved uncoupling. Up from around 25% uncoupling to around 75% of the cars.
With the MT magnet 50x7x3mm (measured) cars now separate at the very end of the magnet meaning to move it up further will require a longer or just more short magnets.


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Well-Known Member
I started playing around with magnets under a piece of test track, and I see how each coupler gets pulled to the "short side" of the track.

Seems the leading coupler's air hose points a little to starboard, while the trailing air hose points a little to port. And when the joined cars go over the magnet, the leading coupler is pulled to starboard while the trailing coupler is pulled to port. I see how there must be slack, or the magnet won't actually pull either air hose in either direction.

I know what I just said is probably common knowledge, but it's something I learned today!

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