Has anyone tried neodymium (rare earth) magnets as an uncoupling device for O scale Kadee's?

I have played around with these magnets in S gauge without much success. There was conversation about this on a "scale" venue but I could not get much help being an American Flyer user. I would like to find out more about this also.

Ray

Ed,

Can you provide a link to the YouTube videos?

I know that dipole magnetic fields decay at the cube of the distance.  But you have two parallel rows of dipoles so they will behave differently and to your advantage. Is this what you are thinking?

I've looked at but not touched the 3-rail Kadee system, and they use bar magnets that I suspect are really a row matrix of discrete magnets.  There is a YouTube that Hot Water did on the O gauge version.

The steel plate conducts the magnetic flux under the rails making the magnet act like a horseshoe magnet.  The row of magnets takes the dipole (point magnet) and turns it into a 2D magnet which does not behave by the inverse cube of distance but my the square. 

The distance becomes key.  You may want to consider grooving the underside of the ties to move the magnets and their field closer to the coupler pins. 

Considering that HO distances are about 1/2 those of O you will need magnets at least 4 times as strong.  I hope a real physicist will chime in.

Jan

I have tried with no success. I even tried magnets 20+ pound pull. I think it is more of an affected surface area than anything. How does the rows of multiple magnets work? Do they touch, I would assume the poles would have to be lined up?

My most recent install I replaced the Gargraves ties with 1/16" thick ones, removed the bottom web of the rails and replaced the center rail with a piece of code 100 nickel silver weenie scale rail. All in the name of improving performance. My next install I'm think of replacing all 3 rails with Atlas O rails spiked to the Gargraves ties. My big issue is performance, Kadee's work most of the time but the as built Atlas do not work at all. Atlas couplers with the original spring replaced with Kadee knuckle spring work 1/2 the time.

Steve

I did an article in the July/August issue of The O Scale Resource showing step by step how I did it and a video also.

http://oscale.uberflip.com/i/532266-july-august-2015

Thanks Dan,

Have you noticed that you have to be exact in your car movements to make the cars uncouple?  Would adding a third or even fourth set of magnets make things easier?  Is the ability to push two uncoupled cars effected?  Did you try putting a strip of steel under the magnets?  Do you know what strength of magnets you used?

Jan

Jan,

Not really exact, just almost stop over the magnet and it will uncouple. The video shows better then I can explain. The magnets are just Super Magnet brand as shown. I used the size that would fit as close as possible between the ties.

Helpful replies guys.  I'm going to give Dan's approach a try but with two rows of 3 or 4 magnets for easier spotting. The use of drywall screws to position the magnets was very clever.  Jan's approach with a steel retainer plate would strengthen the magnetic field but I'm not sure I'd need the added strength - particularly since I don't use Kadee's delayed uncoupling feature (where the heads offset).  My objection to delayed uncoupling is that it requires an additional back and forth move to pick up a car spotted over an un-coupler.  To defeat the delayed uncoupling feature recently I've replaced the soft Kadee draft gear springs with stiffer ones of the same size.  The goal is to have the uncoupler's magnetic field strong enough to  open the knuckle - but not strong enough to pull the coupler shank off its center line. So far the test results over Kadee uncoupling magnets have been positive.    I'll need to do more testing after installing several neodymium magnet uncouplers (using Dan's approach) in my branch line yard and on several mine tipple tracks.

Dan,

Do you think your method would work with steel rail?

Thanks,

Ed

I experimented with this idea and made it work in various configurations.. You may want to put a figure or a yard sign as a spotting reference next to the track to hit the sweet spot for uncoupling. Subsequently I decided to go manual for the involvement, as well as, not having to install a bunch of these magnets. The ones I used were about 5/16s in diameter.

Ed Kelly posted:

Dan,

Do you think your method would work with steel rail?

Thanks,

Ed

I don't see why not. Once you position the magnets on the screw heads and glue, you should be fine.

I don't use magnets as I have on board uncoupling, but I operate on an HO layout which has them and they work perfectly.  He's simply removed one tie and replaced it with a row of cube magnets.

Home Depot offers these magnets, I purchased some to try after reading dans article.

Try these guys for rare earth magnets.  They offer them from 1/16 diameter up to huge.

https://www.kjmagnetics.com/products.asp?cat=1

MaxSouthOz posted:

I don't use magnets as I have on board uncoupling, but I operate on an HO layout which has them and they work perfectly.  He's simply removed one tie and replaced it with a row of cube magnets.

Hi Max

What is onboard uncoupling?

Thank you

Clem k

Hi Clem

Each vehicle has a decoder inside.  The decoder drives two muscle wires (wires used for electric prostheitcs - which shrink from the small amount of heat generated as a current passes through).  Each muscle wire pulls a piece of black cotton which is connected to the outer jaw of the coupler.

Here's a car I'm building, with the gubbins already inside.

It's going to be a hopper car.

Here's a movie of the prototype . . .

Cheers

Thank You Max 

Clem k

Success!!  I completed a series of tests using parallel rows of 8mm x 3mm "super" magnets installed per Dan's approach and found that they were easy to install and work very reliably with Kadee couplers.  I drove the drywell screws down flush with my Homosote roadbed and cut out the plastic ties in the area. I found with exact spotting one could uncouple cars with as little as 2 magnets.  For easier spotting I've settled on using two rows of 3 magnets.  I didn't try using a steel retaining plate as the little magnets are plenty strong as is.  On the drywall screw heads the super magnets sit just below the height of the ties - perfect for hiding them under a layer of cinder ballast.  Something I could not do with the Kadee 811 between the rails uncoupling magnets as they had to be positioned at rail height for reliable uncoupling.

I ran the tests with 6 cars using standard Kadee draft gear springs and 6 other cars retrofitted with stiffer Athearn truck springs.  The cars were a mix of plastic Kadee 804's and metal 805's.  Uncoupling and coupling performance worked equally well with both spring types over the neodymium magnets .  For those that want the delayed action feature stay with the standard Kadee springs.  For those that don't want the extra back and forth motion required to couple to a car over a ramp (delayed action) the stiff draft gear springs worked great.  They also reduce some of the extreme slack action one gets with soft sprung Kadee's.  

Now for the economics.  Kadee 811 between the rail magnets list for $5.15.  My test pack of of ten 8mm x 3mm "super" magnets cost $9.95 at my local hardware store.  On the internet I ordered 150 N35 magnets for $17.04 - which works out to $.68 for each un-coupler.  A great price for a easy to install fully functioning hidden un-coupler.

Excellent, Ed. 

Keystoned Ed posted:

Success!!  I completed a series of tests using parallel rows of 8mm x 3mm "super" magnets installed per Dan's approach and found that they were easy to install and work very reliably with Kadee couplers.

Ed, Glad it worked for you. The Kadee 811 is fine IF you remember to install it when putting down your track. But a retrofit was going to be a mess. A few hours, a box of magnets and screws and a beer or two... what could go wrong :-)

Good afternoon

Will these work with the newer #740 coupler ?

Thank you

Clem k

Ed, video time!!!

Ed I would really like to see pictures if thats possible

Thank you 

Clem k

I'll take some pictures and a video and post them tomorrow. 

I know this is S gauge but you should find it helpful.  I posted this 1/4/15:

THE SECOND TRY FOR THE PHOTOS...

I am posting a few pictures of my ongoing experiments with magnets and Kadee #5 couplers.  I have been able to overcome the trouble I was having with Flyer link couplers with metal weights.  Each of the following solutions works well, that is, has no problem with Flyer links sticking to the magnets.

First up is what I hope will be what I end up using because of cost (always a big thing with me).  It has two magnets (J&K number BX841) that are 1½” x ¼” x 1/16” separated by ½”.  The BX841s are $1.10 each making for a $2.20 uncoupler... I like that.  The ties are .03” cardboard, the magnets are colored to show polarity (black – north & red – south) and the rail is .138” SHS flex.  That places the magnets .168” below the rail head.  I tried .06” ties and found the .03” difference really made a big difference with the performance of the couplers… it short it didn’t work.

I am finding this solution marginal in that my Kadees don’t all perform the same.  Some work beautifully while others don’t.  I expect my lack of experience with the Kadees accounts for this -- I hope --- because I do like how this all goes together. .  I have included a second picture showing how the couplers respond to the delayed action.  Please note that one of the cars has scale wheels while the other has Hi-rail wheels.

Next up is the same arrangement but with 3/8” between the magnets.  It is still .168” below the rail head.  I think the extra 1/8” of the first example is better to pull the Kadees over for delayed uncoupling.  I also didn’t add the ties.  This was my first experiment.  I can add 1/16 x 1/16 styrene to change the separation between the magnets.

Then the last one and perhaps the fallback position.  This are B822, ½” x 1/8” x 1/8” mounted on .02” sheet metal.  The B822s are $.43 each but  10 are needed so the cost per uncoupler is $4.30.  They are too strong as you will see by the photo.  Although I have not had a problem with the couplers being pulled this far apart, they just don’t fit into each other’s pocket.  I have ordered some B422, ¼” x 1/8” x 1/8” magnets with the hope they won’t be so over the top.  The cost of the B422s is $.27 each or $2.70 per uncoupler.  If they work it would be afforadable.

I have also ordered some wider magnet that the BX841 thinking they might provide a bit more pull to get the balky Kadees to pull apart.  The wider magnets are $2.00 each for a $4.00 uncoupler – more than I would like to spend, but if that is what works, then so be it.

I haven’t played with AM .148” rail yet and I hope that the .010” difference doesn’t cause a problem.  I have to say I was surprised that .030” did make a difference.  People who aren’t going to run Flyer link couplers across their magnets will find much easier solutions and for the ones using like code 100 or small rail ,I think you could just add a pair of 1½” x 1/8” x 1/16” magnets on top of you ties… be sure to glue them in place.  I have found that 1½” long uncoupler is an easy target to land on even without DCC.

Tom Stoltz

in Maine

I've had no trouble installing Kadee 811 magnets in previously laid flex track.   I just cut the plastic ties (4)  inside the spike heads using a sharp drywall knife or a Dremel cutoff wheel.  Over the years I've done dozens of ramps this way.  My main objection to the 811's is that their magnetic field isn't strong enough to mount them hidden under ballast or cinders.  To improve the appearance of yard and industrial trackage I'm going to replace all the Kadee 811's (30+) on the railroad with the neodymium magnets I just ordered.  Tomorrow I'll take some photos and videos of my test installation in the Oceola Mills branch line yard.   

I bought a KD electro magnet thing a few years back. It was supposed to work when energized. I actually forgot about it as it's packed away with scenery stuff. (that's a whole 'nother story.)

Someday I figured I would test it and other magnets. I used to have the regular track magnets in HO scale and got used to using them with the KD couplers. I think switching adds interest and fun to operations.

Clem  I like the appearance of the new 700 series Kadee couplers but  ran into trouble when I installed them on several brass Yoder hoppers, and in the pilot beam on a Key H10.   In most applications you can use the plastic pockets tthat come with the Kadees 700's - but not all.  The issue manifested itself when I was demonstrating the operation of the new couplers to a friend.  I had a string of four Yoder GLa hoppers coupled to a brass Nd 4 wheel caboose which previously had plastic 804 Kadees.  When the locomotive coupled up to the cut of cars a short passed through 10 couplers from the locomotive to the caboose (all intervening cars had insulated trucks.  A fast acting DCC breaker protected the decoder, but not before all the small hidden Kadee knuckle closure and the draft gear springs in the 10 couplers were destroyed! 

I've also observed that mixing 700 and 800 series couplers doesn't yield as reliable operation as standardizing on one type both for reason of gathering range on slight curves and uncoupling.  For those cars on my roster that will be involved in intensive switching operations (not the whole fleet), I'm going to standardize on the old 800 series couplers as I believe they yield the most reliable hands off operation.

 -

Good morning Ed

 Thanks for getting back to me, I find the old 800 series work much better with magnets then the new 700 series.

Clem  

That figures. I started putting all the new couplers on my engines exclusively as I liked their looks. I bought the older ones in bulk and use them on the cars. I haven't had shorts. I haven't tried any magnets though. I did notice that the uncoupling arm is bent more circular on the new ones and even at a slightly different height?

It looks like it may bite me.... later on.

Joe it might just be me and my trains, I found a magnet store in Toledo that I will go to on monday.  I'll try the magnets suggestions made on this thread, the S gauge post is interesting.

Thank you Dan, Ed, Tom, and everyone else. this is a good thread,thats this weeks project to get these Kadees to work reliably remotely.     Joe sure wish you would try that electrical magnet.

Clem k