Weekend Update 2/5/17

[chuck geiger]

Getting tanked for Superbowl:

[peteski]

My understanding is that they will work but they'll need to be mounted sideways. Kadee and Micro-Trains couplers need the poles of the magnet running across the track, to pull the couplers away from each other. There are some British designs of magnetic couplers that need a vertical pull, so putting the magnet face up works for those.

There used to be an ad in the N-Scale magazine for under-the-track uncouplers which used those small flat rare-earth disk magnets.  The ad actually had a drawing of what it looked like. It was a steel plate with a disk magnet on each corner. I assume that the disks on one side of the track had their south poles facing the metal plate and the other side had the north poles facing the plate.

[nkalanaga]

That's the way I remember it as well, south on one side, north on the other.

[narrowminded]

I have played with those magnets when trying to understand the way those couplers work.  And they do!  Basically you put at least one on each side as noted, approximately centered under each rail.  Fix one under one rail and then check which way the second one repels and that's the up side for that one under the opposite rail.  Try magnets that are 1/4" to 5/16" in diameter, 1/16" or so thick and set up a test rig on the table with some double back tape and roadbed.  With this you can play with the gap under the rail and the side to side placement before to fix permanently on your layout.  You can add additional magnets on each side spaced about 3/8" to 1/2" apart to increase the uncoupling position window but you may find that's not necessary.  If doing that, maintain the same polarity for the magnets under each rail.  They can also be stacked/ doubled for more power but be careful that you don't get too much so that it wants to uncouple when passing forward over the magnets.  One each side should do it and shimmed closer to the rail or all of the way down to the bed should be sufficient to find a workable range. 

Also, an extra precaution if you have closely spaced adjacent tracks with adjacent uncouplers, like in a yard, it is best to alternate the polarity of the magnets not just on your rail but then follow by alternating the polarity of the magnets under the adjacent track so the two tracks don't interfere with each other.  Any magnets in adjacent tracks that are near each other always staggered, one north, next south, next north, and so on.

[peteski]

I have played with those magnets when trying to understand the way those couplers work.  And they do!  Basically you put at least one on each side as noted, approximately centered under each rail.  Fix one under one rail and then check which way the second one repels and that's the up side for that one under the opposite rail.  Try magnets that are 1/4" to 5/16" in diameter, 1/16" or so thick and set up a test rig on the table with some double back tape and roadbed.  With this you can play with the gap under the rail and the side to side placement before to fix permanently on your layout.  You can add additional magnets on each side spaced about 3/8" to 1/2" apart to increase the uncoupling position window but you may find that's not necessary.  If doing that, maintain the same polarity for the magnets under each rail.  They can also be stacked/ doubled for more power but be careful that you don't get too much so that it wants to uncouple when passing forward over the magnets.  One each side should do it and shimmed closer to the rail or all of the way down to the bed should be sufficient to find a workable range. 

The way you described your setup seems that you don't use the steel plate but just the magnets themselves.  To me that steel plate seems important: it concentrates and directs the magnetic force for most trouble-fee uncoupling, and keeps the magnets aligned properly under the track.

[narrowminded]

The way you described your setup seems that you don't use the steel plate but just the magnets themselves.  To me that steel plate seems important: it concentrates and directs the magnetic force for most trouble-fee uncoupling, and keeps the magnets aligned properly under the track.

Nope.  I just used the two magnets, one each pretty much centered under each rail.  Extending the lengthwise working range plates might work well but even there, in my test rig I just added another set of magnets.  If I use this I think it will just be two opposite magnets with the 1/2" or so working window that those afford. 

You must have some of those magnets laying around as well as a piece of track.  Take a minute and rig it up.

[narrowminded]

Let me just add for additional clarity.  I recommended rigging this up and testing because there are different sizes but also different strengths available in those magnets.  And my concern from my testing was not a fear of having enough force, but having too much.  I also rigged this with N and Z track and the Z was almost too much force.  With the cars being so light even going forward, a sneeze would uncouple them.  And with N track it worked fine but there was a noticeable difference in sensitivity with just the difference in rail height between code 80 and code 55.  I didn't finish this nor have I actually installed any in a layout, just the bench rig and testing.  I satisfied my curiosity about how the magnetic couplers worked and realized it was viable if needed. 

I also concluded that if I had the under table room for the electromagnetic rig, positive on/ off, I would definitely go that route.  From what I saw playing with the magnets, I also think they would work on N with no modification but also would prove that out in a rig on the bench and wouldn't be afraid of any modification that might prove necessary.  Hope that helps.

[sirenwerks]

The November 2008 RMC had an article on dual magnet uncoupling (used for HO); there was an article on the steel plate and multiple magnet line-up idea in the September-October 1994 NSM; and the February 2000 MR had an article on a nifty manually-operated, hinged-design that put the plate uncoupling magnet in place only when desired, to eliminate unwanted uncoupling.  I have these articles scanned in if anyone wants them; PM me with your email address and I'll shoot you PDFs (may need to send them one at a time though). 


Bryan

[narrowminded]

The November 2008 RMC had an article on dual magnet uncoupling (used for HO); there was an article on the steel plate and multiple magnet line-up idea in the September-October 1994 NSM; and the February 2000 MR had an article on a nifty manually-operated, hinged-design that put the plate uncoupling magnet in place only when desired, to eliminate unwanted uncoupling.  I have these articles scanned in if anyone wants them; PM me with your email address and I'll shoot you PDFs (may need to send them one at a time though). 


Bryan

A variation on a hinged design also occurred to me.  Two of the round magnets in an appropriately sized pair of plastic tubes (could be brass, I guess), a cut piece of steel round of the same diameter to aid in guiding them without them rolling over in the tube, operated with a rotating steel lever wire form that raised and lowered them.  The magnet would hold the steel guide pieces and wire form together while allowing the necessary pivot and without more fabricated, intricate parts beyond a mounting base with the wire form hinge and tubes attached.  Something that should be able to be knocked out and glued up from standard available plastic, seems to me.   But then there's still the cable or linkage to the facia.   

[Chris333]

More HOn30. On my small mining layout I had built a coal tipple, but it just looked too big on this small layout. I found a photo of a smaller tipple
http://www.whitbywv.com/tip2.html
When I printed out the photo the people were perfectly HO scale. So I traced the photo and started on a new smaller tipple.

Old one:


New:

[basementcalling]

A variation on a hinged design also occurred to me.  Two of the round magnets in an appropriately sized pair of plastic tubes (could be brass, I guess), a cut piece of steel round of the same diameter to aid in guiding them without them rolling over in the tube, operated with a rotating steel lever wire form that raised and lowered them.  The magnet would hold the steel guide pieces and wire form together while allowing the necessary pivot and without more fabricated, intricate parts beyond a mounting base with the wire form hinge and tubes attached.  Something that should be able to be knocked out and glued up from standard available plastic, seems to me.   But then there's still the cable or linkage to the facia.   

I've wondered but never tested if those magnets would work if mounted to a U shaped piece of plastic you could lower from above like a coupler pick, but instead of manually forcing the couplers apart with a twist, just lowering the magnets onto either side of the space between cars might trigger the delayed uncoupling feature.

Thoughts?

[C855B]

I've wondered but never tested if those magnets would work if mounted to a U shaped piece of plastic you could lower from above like a coupler pick, but instead of manually forcing the couplers apart with a twist, just lowering the magnets onto either side of the space between cars might trigger the delayed uncoupling feature. ...

I've seen this technique documented. Just can't remember where.

[Sokramiketes]

I've seen this technique documented. Just can't remember where.

The Rix Sticker

[bbussey]

I've been wondering if rare earth magnets could be embedded between the rails for use with magne-matic couplers.

K&J Magnetics in Pennsylvania makes small flat neodymium magnets with the proper pole orientation in their BX series that can be buried in the roadbed outside of the rails and will properly operate Micro-Trains compatible magnetic couplers.  I don't remember the specific item numbers offhand currently but I will report back later.  The cost varies based on magnet dimensions and quantity purchased, but the unit price is well under $1 each.  You would need two per uncoupling location, one for each side of the tracks.

[peteski]

K&J Magnetics in Pennsylvania makes small flat neodymium magnets with the proper pole orientation in their BX series that can be buried in the roadbed outside of the rails and will properly operate Micro-Trains compatible magnetic couplers.  I don't remember the specific item numbers offhand currently but I will report back later.  The cost varies based on magnet dimensions and quantity purchased, but the unit price is well under $1 each.  You would need two per uncoupling location, one for each side of the tracks.

If the magnet is a long flat part with lengthwise poles then why are 2 needed?  The MTL between-tracks magnet or the larger Kadee under-track magnet are all single pieces with the magnet centered under the track.

EDIT: never mind - I recalled discussing this subject here in the past and I found the explanation in this thread: https://www.therailwire.net/forum/index.php?topic=34638