Trains.com

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Super magnets for uncoupling

7014 views
42 replies
1 rating 2 rating 3 rating 4 rating 5 rating
  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Thursday, May 12, 2022 10:37 AM

Bought mine on ebay. Since I use cork over foam, I drill 1/8" holes just thru the cork and insert the magnets which are 1/2" long, don't even have to glue them in.  Yeah it has worked out better than I imagined, surprised Kadee dosn't sell them with a markup of course. The only problem I have had is with a bobber logging caboose as they are so super short the magnet tends to grab the pin too hard but that only seems to happen with the stronger magnets also could be fixed by bending the pin up a bit more than normal. Like I have said before, I tried to test everything to find flaws, including every coupler brand I own which includes knockoffs from most brands including such cars as stock Ertls, like I said I tried everthing I could find. Another note, these magnets will identify drooping couplers, have a Backmann 70 ton engine like that, had to tighten the screws LOL.

  • Member since
    February 2008
  • 2,360 posts
Posted by kasskaboose on Wednesday, May 11, 2022 9:07 PM

 

rrebell

Finally got my N52 magnets and they do work even better. Ended up useing two per side with polarity different on each side with magnets as close as possible to the rails. I also placed each side with the first magnet further from the trip pin by one tie so say each side has three possible spots, facing the magnets looking down the rails the left side would be 1 and 2 and the right would be 2 and 3. The reason for this was to use less magnets and when using an engine it was much more reliable. Also of note is that with the N52  you could uncouple cars wth the magnet under the ballast but not the engine.

 
 
RREBELL,
 
Where did you get the magnets?  Did you need anything special to put them under the track?
 
It seems too easy.  You have given me (and possibly others) such confidence.  Thanks!
  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Wednesday, May 11, 2022 11:35 AM

Magnets are now installed and work great. Didn't need any on the main except one place so working on a design that uses weaker magnets as an asist to the dental brush pick to make it impossible to have an accidental uncoupling on the main instead of the 99% under current design. Also got to come up with a way of seeing the sweet spot for uncoupling on the others, seems I got too good at hiding them, well I did want them hidden!!!

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Saturday, April 16, 2022 12:00 PM

Finally got my N52 magnets and they do work even better. Ended up useing two per side with polarity different on each side with magnets as close as possible to the rails. I also placed each side with the first magnet further from the trip pin by one tie so say each side has three possible spots, facing the magnets looking down the rails the left side would be 1 and 2 and the right would be 2 and 3. The reason for this was to use less magnets and when using an engine it was much more reliable. Also of note is that with the N52  you could uncouple cars wth the magnet under the ballast but not the engine.

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
  • 18,255 posts
Posted by SeeYou190 on Monday, April 11, 2022 11:17 AM

cowman
How slow can you go and they not come uncoupled?

As long as there is no slack in the train, as slow as you want to. You can even stop, as long as you do not go backward the Kadee couplers will stay coupled.

All of my cabooses have wipers on the axles that provide a little resistance so the train stays coupled.

When just switching with no caboose, very free-rolling cars can still experience accidental uncouplings over 308 permanent magnets when going very slow.

-Kevin

Living the dream.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Monday, April 11, 2022 10:47 AM

Still waiting on n52's out of Canada, I swear I get stuff faster from China than Canada these days.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Saturday, April 2, 2022 11:34 AM

Further experiments have shown that this method of uncoupling is not as reliable on engines that are not Kadee equiped. Still experimenting with new combinations and placements. On a side note, I have learned to paint the magnets so the disappear almost in my WS grey blend ballast.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Thursday, March 31, 2022 12:20 AM

Anyway I am still experimenting, strange thing I found out that using two magnets with oposite poles on each side on straight track enhance the uncoupling action but doing the same on a curve makes it not work at all, why? Also found the some non Kadee couplers are less reliable but other are just fine with those used on Proto 2000 being the worst (but then a lot of you would say duh, but I always double check things for myself).

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Thursday, March 31, 2022 12:11 AM

ClydeSDale

 

 
rrebell

For the magnets I use drill 1/8" hole, done.

 

 

I thought this was an information sharing forum, not a contest .....

Well, here you go rrebell, a nice pat on the head.  You win .....

 

 

???????????

  • Member since
    February 2016
  • 18 posts
Posted by ClydeSDale on Saturday, March 26, 2022 8:59 PM

rrebell

For the magnets I use drill 1/8" hole, done.

I thought this was an information sharing forum, not a contest .....

Well, here you go rrebell, a nice pat on the head.  You win .....

 

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Saturday, March 26, 2022 3:07 PM

For the magnets I use drill 1/8" hole, done.

  • Member since
    February 2016
  • 18 posts
Posted by ClydeSDale on Saturday, March 26, 2022 2:40 PM

I have a 40" x 12' switching layout (switchers and 40' or shorter cars) and I'm a big fan of touchless and delayed uncoupling with KD's.  I started out using the #321's between the rails (unsightly and inflexible), tried the #308 under track magnets (hassle to install or modify placement), experimented using Harbor Freight rare earth 5/16 x 1/8" disc magnets held apart by a styrene strip with concave ends (adjustable for use on curves).

For the bulk of my uncoupling spots I have settled in on using 3mm cube magnets that fit five wide between the ties and rails quite nicely. When installed there is just the right amount of top clearance to activate the KD's but not conflict with anything passing over.  To install I lay out a long string in a magnetically comfortable order and mark every fifth one with a black marker.  When I install them between the ties, one strip at a time, and glue them down the black cubes are all on one side orienting the magnetic pull.  I usually use them in 3 strips of 5 but I've also played with a 5-4-5 configuration.  After install they can be camouflaged with paint or ballast without affecting performance.

I mark the uncoupling spots with power poles, light poles in the yard and white posts.  I really like doctorwayne's idea of a yellow post with a black band or bands in easily visible spots.  Another project.  Since I usually operate the whole layout from one area the poles act as taller than rolling stock uncoupler locator.

It became a trial and error project with an outcome that I've been quite happy with.  Now my largest conflict has become projects vs operating time. Smile

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Wednesday, March 16, 2022 12:29 AM

maxman

 

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

 

A sketch?

 

No way to post.

  • Member since
    February 2008
  • 8,877 posts
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?

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
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.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
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.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
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.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Monday, March 14, 2022 10:26 AM

Now to perfect the curves if posible.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
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.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
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.

  • Member since
    January 2009
  • From: Bakersfield, CA 93308
  • 6,526 posts
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.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
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.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
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.

  • Member since
    July 2006
  • From: 4610 Metre's North of the Fortyninth on the left coast of Canada
  • 9,352 posts
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."

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
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.

  • Member since
    May 2020
  • 1,057 posts
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.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
Posted by rrebell on Monday, March 7, 2022 2:48 PM

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

  • Member since
    May 2020
  • 1,057 posts
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.

  • Member since
    July 2006
  • From: west coast
  • 7,667 posts
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?

Subscriber & Member Login

Login, or register today to interact in our online community, comment on articles, receive our newsletter, manage your account online and more!

Users Online

There are no community member online

Search the Community

ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT
Model Railroader Newsletter See all
Sign up for our FREE e-newsletter and get model railroad news in your inbox!