Cars not uncoupling at crest of the hump (N Scale)

[videobruce]

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.

 

[JeffH]

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.

 

[logandsawman]

There must be a little slack when over the magnet. The slightest pressure on the coupler will prevent it from opening.

 

[flyboy2610]

There must be a little slack when over the magnet. The slightest pressure on the coupler will prevent it from opening.

X2.One car is pulling one way, the other is pulling in the opposite direction. There is no slack in the couplers to allow uncoupling to take place.

 

[videobruce]

On the 'problem' cars I'm not sure if both knuckles are opening. The other cars it's a 'textbook' operation when they separate.

 

[dave1905]

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.

 

[videobruce]

I was aware that humps are not common which is why I wanted one.

 

[logandsawman]

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.

 

[PowrCab]

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.

 

[videobruce]

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.

 

[JeffH]

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!

 

[videobruce]

I received my 1st set (of 2 sizes) of Neo magnets I ordered from China (a week earlier than the earliest estimate no less).
I tried these Neo magnets and they pull the couplers together no matter which way I placed the magnets. Instead of uncoupling they do the opposite. I tried taking some pics but it doesn't show up as well as I would of liked.
Compare those w/ the 3rd attachment. MT's magnet works, these super magnets do not. I even stacked two and other then it was stronger (probably because of height) the 'trip pin' still gets pulled inward, not outward on both cars. (Those magnets were not secured down. When the trip pin came close enough the magnet lifted up to the pin.)

 

[JeffH]

I'm guessing here, but I believe the issue is with the alignment of the poles of the magnet.

I believe that the MT and other magnets that are designed for uncoupling have their poles aligned perpendicular to the tracks, meaning a north pole is near one side of the track and the south pole is near the other side.

Metal is attracted to each pole of the magnet. If your new magnets are oriented such that the poles are parallel to the tracks, or if they point up and down, then they will not uncouple.

To uncouple, the trailing coupler of the leading car is pulled left, while the leading coupler on the trailing car is pulled right. If the magnetic poles are both in the center of the track, then both couplers are pulled to the center of the track.

 

[videobruce]

I'll try those tests and report back.

In my situation, magnets can only be between the rails as they are now with a MT magnet, or outside the rails which I did try, but since they weren't glued down the test was meaningless. There is no under the table access since this (the crest) is up on a raised portion probably four inches above the table level which consists of 3/8" ply and 1/2" rigid foamboard.

 

[videobruce]

The poles of the magnets are the top and bottom of each one. Being the size is so small, it's hard to reposition them sideways, but it made no difference, they just won't work.
I got the link and suggestion elsewhere to try those.

I temp placed two stacked magnets against the rail to see what happens. Nothing!

 

[JeffH]

Can you place the magnet inside the rails when it is perpendicular like that? If not, you can shorten the magnet a bit by chopping off a small amount from one side. That won't damage the magnet, and it will rule out the magnet as being the problem.

It's possible that the magnet being on the outside of the rail isn't quite strong enough. it's also possible that the poles in those magnets are oriented "up and down" or "front-to-back" rather than "side-to-side."

 

[JeffH]

This is a really good video. It's all good, but you can jump to about the 9:00 minute mark to see what I'm talking about with getting the magnetic poles under each rail. Again, this is HO scale, but the concepts are the same with N scale.

 

[videobruce]

I would have to try it.

I received the MT magnet set (2) and discovered that the N & S poles are centered around the sides of the magnets which makes sense based on the direction the 'trip pin' is facing.
On these small silver bar magnets the poles are on the top & bottom making them semi useless unless one positions them standing up om their side which isn't practical in my situation. The cost difference in nil.

The solution was to cut one in half and extend the length which seems to solve most of the problems. It needed a longer reach past the crest which was the last problem. I still have a few exceptions which I'm dealing with the specific cars.