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Super magnets for uncoupling

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Super magnets for uncoupling
Posted by rrebell on Friday, March 4, 2022 12:47 PM

Woulda, shoulda, coulda, magnetic uncoupling. Wish I would have gone with under track magnets but layout is mostly finished except for super detail parts. So this leaves the super magnet option. So what have you used, type, spacing, any proublems?

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Posted by BATMAN on Friday, March 4, 2022 12:56 PM

Sonicare toothbrushes have really strong magnets in the brush heads that you replace when they wear out. They are quite small like an eraser on a pencil and when inserted on either side of the track they work perfectly to uncouple cars. I just poke a hole in the foam, insert the magnet and then throw some ground cover over it.

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by wrench567 on Friday, March 4, 2022 1:59 PM

   I had some quarter inch square ones left over from another hobby. When I built the track scale module I put one under each rail across from each other on the approach rails to the scale.

  I suppose you could get some quarter inch round and put one on each side. Or some 3/16 round and try inside the rails and cover with ballast. K and J magnets is my go to magnet shop.

    Pete.

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Posted by RR_Mel on Friday, March 4, 2022 2:33 PM

I use ⅛” diameter by ⅜” long Neodymium magnets for all kinds of goodies from uncoupling to keeping structures attached to my layout.

https://appliedmagnets.com/neodymium-magnets-1-8-in-x-3-8-in-rare-earth-cylinder-n42/

Simple ⅛" hole and your in business.

Mel


 
My Model Railroad   
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Turned 84 in July, aging is definitely not for wimps.

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Posted by MisterBeasley on Friday, March 4, 2022 4:41 PM

Wooden bamboo skewers.  I have always sort-of liked magnetic or other remote uncoupling, but the ability to uncouple anywhere eventually won out.

I still have a few magnets in awkward spots.  Yeah, they are electro-magnets installed as the track got laid.

It takes an iron man to play with a toy iron horse. 

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Posted by BroadwayLion on Friday, March 4, 2022 5:04 PM

Magnets do nothing for units coupled with drawbars, which is all I run now.

You know all about Kadee magnets. N and S are along the edges so that the trip pins are pulled away from each other.

Now you can buy super magnets from All Electronics cheaply enough, but you can get the same for free for each old hard drive that you take apart. Same magnet and very strong.

TEST THIS MAGNET to determine how the trip pins react to it. In my experience they must be placed perpebdicular to the running rails instead on pzrallel as with a Kadee magnet. On the bench just put the magnet under a test track and see what orientation opens the trip pins.

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Posted by doctorwayne on Friday, March 4, 2022 5:26 PM

I get my super magnets at Princess Auto (only in Canada, I think).  A month-or-so ago I decided to try adding an uncoupling site to one of my industry tracks.  While the area there isn't yet finished, scenery-wise, the track had been ballasted (it's directly on the plywood - no cork).
I sprayed a little "wet" water on the area, then used a screw driver to remove most of the ballast from between four ties, then used a #11 blade in my X-Acto to cut-away the connecting material between the ties, then pushed-apart  the two ties in the centre.

Next, I used a "O" size drill bit (.3160" in diameter - the same diameter as the 8mm diameter of the magnets) to drill a shallow hole in the plywood on the inside of each rail, roughly 3mm deep, which is the thickness of the magnets.

I then place a small dab of WeldBond cement in each hole, then pressed the magnets in place, both with the same polarity facing up.  The two ties were then pushed back to roughly their original position, just barely over the edges of the magnets.
Next, I added some ballast, groomed it, then sprayed the area with "wet" water and applied some diluted white glue.

The next day, with the glue set, I used a locomotive to push one car over the magnet, which opened both couplers and deflected the trip pins, allowing the car to be spotted where I wanted it.

I have 48 of those magnets left, and another 50 of the same diameter, but thinner....I'd double the thinner ones for uncoupling purposes.

That will be more than enough to do every industrial siding on my layout. 

The benefit of using these small magnets is that there's not a lot of mess created to install them in sites where the track has ballast or ground cover of some sort, and no need at all to take-up track, as would be required for Kadee under-the-ties uncoupling magnets.

I do have some of the larger rare earth magnets, which might work where uncoupling could be more difficult, but the small ones work just fine where I plan to place them.

I mark all of my uncoupling magnets with a yellow post (Evergreen styrene rod) with a black band...

...and if there are two or more tracks parallel, with magnets in a similar position, another band is added for each such track...gotta keep on-budget with my post supplies, eh?

Wayne

 

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Posted by cowman on Friday, March 4, 2022 5:28 PM

Not to steal the thread,  but how slow can you go and they not come uncoupled?

Thamks,

Richard

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Posted by doctorwayne on Friday, March 4, 2022 5:56 PM

For mine, both the ones mentioned and the larger Kadee under-the-track or between-the-rails ones, they'll uncouple while the train is not moving, with the couplers over the magnets.  I don't generally do flying drops.

Wayne

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Posted by John-NYBW on Friday, March 4, 2022 6:26 PM

Early on, I removed all my under-the-track magnets from the mainline due to unwanted uncoupling. I now use them exclusively in yards and spurs.

I'm intrigued by these super magnets. I use uncoupling tools for mainline uncoupling but I do some switching of passenger cars and the diaphragms make that impossible. I've tried coming in from the side to seperate the pins but just can't get the hang of it. I'm wondering if a few well placed super magnets at my main passenger station could be the answer. 

How big are these magnets? Are they placed between the rails or outside the rails? Is unwanted uncoupling a problem? I'm not interested in the electro-magnets. 

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Posted by rrebell on Friday, March 4, 2022 7:25 PM

I got a bunch of the skewer type with lights but I just don't like them as much. My whole layout is cork on foam except for an area around the turntable so drilling 1/8" holes is appealing as ballasting is done. What I am looking for are exact placement and how many in a row. How many in a row I have seen everything from 1 to 4. Is polarity important or just that they are both the same?

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Posted by doctorwayne on Friday, March 4, 2022 8:56 PM

John-NYBW
Early on, I removed all my under-the-track magnets from the mainline due to unwanted uncoupling. I now use them exclusively in yards and spurs.

Most of my under-track or in-track Kadee magnets are in staging yards, and they work fine.

The magnets that I use (in my earlier post) are 8mm in diameter and 3mm thick. They're located between the rails, with their outer edge roughly even with the inside edge of each rail.  Both magnets need to have the same polarity facing up, and as long as you do so, it doesn't matter which polarity (positive or negative) is the one that's facing up. 

Right now, I have only one in use, but when I get around to adding more, I'll likely install the magnets with the same polarity as the originals, facing up.  It's easy enough to figure which side should be up, if I simply drop one near to the installed ones, as it will flip to match the ones already installed.  These magnets are much more powerful than the ones most of us, as kids, used to play with.

I also have some bigger ones, but they're considerably more powerful - any rolling stock running on wheelsets with steel axles might be stuck there forever....just kidding, but for uncoupling, they'd be overkill.
The small round magnets are easy to install, as long as you have a drill bit of the same size.

Wayne

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Posted by BroadwayLion on Friday, March 4, 2022 9:02 PM

Yes, uncupling can be an issue with these very slow locomotives. I followed the practice of the New York City Subway (on my last layout before I switched to model subways)... An use a cutting key. All this is is a momentary contact reversing switch, which ever so briefly reverses the direction of the locomotive. So briefly that an observer would not know what I did, but that is enough to uncupple the cars.

 

The Route of the Broadway Lion The Largest Subway Layout in North Dakota.

Here there be cats.                                LIONS with CAMERAS

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Posted by BigDaddy on Saturday, March 5, 2022 5:58 PM

doctorwayne
The magnets that I use (in my earlier post) are 8mm in diameter and 3mm thick. Both magnets need to have the same polarity facing up,

 I used rods, 3mm dia, maybe 8 or 10 mm long, just outside the rails and between the ties.  I did a row of 3 on each side, all the same polarity orientation on both sides.  It did not work reliably.  I have not  revisited the issue, but closer together should work. 

Henry

COB Potomac & Northern

Shenandoah Valley

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Posted by rrebell on Monday, March 7, 2022 8:23 AM

RR_Mel

I use ⅛” diameter by ⅜” long Neodymium magnets for all kinds of goodies from uncoupling to keeping structures attached to my layout.

https://appliedmagnets.com/neodymium-magnets-1-8-in-x-3-8-in-rare-earth-cylinder-n42/

Simple ⅛" hole and your in business.

Mel


 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
Turned 84 in July, aging is definitely not for wimps.

 

Dose the length mater and dose using a higher strength work better or more magnets at a lower strength?

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Posted by wrench567 on Monday, March 7, 2022 9:15 AM

  It depends on what you want them to do. Just uncoupling you only have to overcome the weak knuckle spring. If you want to uncouple and push the car then you need more power to open the knuckle and overcome the centering spring. One magnet on each side should suffice. Any more power and you run the risk of unwanted uncoupling. When ordering magnets look at the pull strength. An N42 1/8x1/4 has a .86 pound pull.

   Pete.

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Posted by rrebell on Monday, March 7, 2022 2:48 PM

How about N48 1/8x3/8 Can get those for a good price.

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Posted by wrench567 on Monday, March 7, 2022 9:00 PM

  Very easy to set up a test track. Will they work for uncoupling? Sure. About 1 pound pull should be powerful enough to uncenter the coupler but weak enough to avoid accidental uncoupling.

  I put very powerful ones under my scale tracks. They cause accidental uncoupling if I pull a string of cars through. But used as intended (pushing cars) onto the scale rails they keep the car from rolling. It's also what I had in stock without ordering. They were bought for holding the canopy on the frame of my RC helicopters and do a fantastic job at that. I've driven my 450 helicopter into the ground a few times and the canopy stayed with the wreck.

    Pete.

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Posted by rrebell on Sunday, March 13, 2022 2:34 PM

Ok, set up test track and installed first sets of two, tried same polarity and oppisite, both worked. Got a curved test track too but will get to trying mags in that later. also need to figure out exact height and distance from rails, got the board, might as well do it all. They ussually work great and am working with #5's and a set of clones just to be fair. Instaltion is real easy as it is cork on foam, just drill though cork and push into the foam, will proubly ACC the final layout ones.

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Posted by BATMAN on Sunday, March 13, 2022 2:58 PM

As mentioned earlier I saved all the little magnets out of worn-out Sonicare toothbrush heads. To test placement distances I glued a couple on the end of two chopsticks to test things out. I suspended a length of track off the ground so I could move the chopsticks under as well as beside the couplers/cars to find where they worked best.

Brent

"All of the world's problems are the result of the difference between how we think and how the world works."

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Posted by rrebell on Sunday, March 13, 2022 6:44 PM

BATMAN

As mentioned earlier I saved all the little magnets out of worn-out Sonicare toothbrush heads. To test placement distances I glued a couple on the end of two chopsticks to test things out. I suspended a length of track off the ground so I could move the chopsticks under as well as beside the couplers/cars to find where they worked best.

 

But you didn't give any exact details as what worked best. Some people just use 1 pair and I have seen 4 pair used.

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Posted by rrebell on Sunday, March 13, 2022 7:25 PM

On curves it seems placement of a larger magnet works best, had some 3/16" ones.

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Posted by RR_Mel on Sunday, March 13, 2022 7:40 PM

I use four pair of ⅛”D x ⅜”L round Neodymium magnets for my uncoupling.  I drill ⅛” diameter holes between the ties against the inside rails.  I adjust the magnetic pull of the coupler rods by the depth of the magnets.

I haven’t had any problems with unwanted uncouplings, some have been in place for several years.  The price was right three or four years ago, 100 for under $4 delivered.

Mel


 
My Model Railroad   
http://melvineperry.blogspot.com/
 
Bakersfield, California
 
Turned 84 in July, aging is definitely not for wimps.

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Posted by rrebell on Sunday, March 13, 2022 10:23 PM

Mine were $20 for 100 but they were 48's also instead of 42's. I was just doing some more experimenting oposite poles and using 2 per side seems to be the sweet spot on the straight.

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Posted by rrebell on Monday, March 14, 2022 10:26 AM

Ok, tried a few brands of couplers and the above worked well on all tried.

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Posted by rrebell on Monday, March 14, 2022 10:26 AM

Now to perfect the curves if posible.

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Posted by rrebell on Monday, March 14, 2022 12:12 PM

OK, curves work perfect too with the inner curve magnet moved in 1/8" appro. Next up is trying doubling up on magnets on the curve or adding an extra row to extend the area of uncoupling.

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Posted by rrebell on Monday, March 14, 2022 9:22 PM

Well I perfected the curved uncoupling, stupid me, if I had to move the inner magnet in, why didn't I relize I had to move the outer one out more, did just on the other side of the rail with the same setup magnet wize as the straight, works and so dose the delay an d so far no accidental uncouplings.

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Posted by rrebell on Tuesday, March 15, 2022 4:09 PM

A little more experimenting, did an offset of the four magnets on a curve (18" radius by the way), so it is as if you used 6 magnet spots but only placed 4 magnets with the side with the pin being 1 and 2 spot and the opposite 2 and 3 spot. hop this makes sense, don't know how else to discribe it. Get almost as much pull as on the straight this way.

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Posted by maxman on Tuesday, March 15, 2022 4:50 PM

rrebell
hop this makes sense, don't know how else to discribe it

A sketch?

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