Magnetic uncoupling options for Atlas Code 55

[shark_jj]

Has anyone found any magnetic uncoupling options for Atlas Code 55.  I have been manually uncoupling cars, but was interested in going back to magnetic uncoupling is some areas that were set back from the front of the fascia.  I know there are electro magnets, but that didn't really interest me.

[nkalanaga]

MT used to make separate between-the-rails magnets that required cutting the ties out, and, on code 55, would probably need part of the roadbed removed.  They also used to make an under-the-track magnet that should work fine.  Cut a hole in the roadbed, put the magnet in it, then lay and ballast the track.

A HO scale magnet under code 55 might be strong enough to work, but I haven't tried it. 

[nscaleSPF2]

These work for me.  They are a little fussy to adjust, but you don't have to remove any ties.  Worked better than the M/T magnets for me.  YMMV.

http://www.modeltrainstuff.com/S-L-Enterprises-N-1-Totally-Hidden-Uncoupler-p/sle-1.htm

[bbussey]

I use a pair of these per each uncoupling spot from K&J Magnetics:

https://www.kjmagnetics.com/proddetail.asp?prod=BX081

I cut out a square inch from the cork roadbed and place a pair side-by-side, then cover with a square of styrene.  Works great, better than the MTL uncoupler and it's hidden.

[shark_jj]

Bryan, excuse my lack of knowledge of magnetics, but why do you require two, side by side.  I understood magnets have a N pole and an S Pole, and the gladhand is drawn to the side by the magnetic field, so why wouldn't just one work?

[nkalanaga]

Because the gladhand is NOT magnetized, so one magnet off-center would pull both couplers to the same side.  One magnetic pole directly under the track would pull the couplers straight down.  You need a North on one side, a South on the other, and a dead spot in between, so that one coupler goes to each side.

Two of the same polarity, one on each side, would work, but only if the magnets are above the track, with the couplers between them.  At least one company makes a manual uncoupler that works just that way, with a small magnet on each side of a two-pronged fork, which is inserted between the cars.

If one could see the magnetic field, a standard uncoupling magnet would have the "field lines" horizontal above the center of the track, bending around and down to enter the ends at each pole.  The gladhands are pulled along the field lines, one to each end, whichever is closest to that gladhand.  Basically the magnet is a standard bar magnet, like the little "stick" magnets kids used to play with, but stretched sideways, so the ends of the stick become the long edges of the magnet.  Picture this as a cross section of the uncoupling magnet, cut across the tracks.

[GaryHinshaw]

I think the magnetic field arrangement in Bryan's magnets is different than depicted above.  The diagram on the K&J site looks like this:



where the orientation is such that the track rails would run in and out of the page, roughly above the high-field (red) regions.  A ferromagnetic metal (like a trip pin) is attracted to regions of higher field strength (more closely spaced field lines), so a trip pin that was initially left of center would move further left and vice versa.  A magnet arranged like you showed would also work, since the field lines converge towards each pole, but the trip pin is not following the field line themselves, like an electric charge would in an electric field.

These rare-earth magnets from K&J are great.  I bet some of them are strong enough to derail a car with truck-mounted couplers. 

[bbussey]

That's definitely the magnetic field diagram for one if the K&J magnets. But David's diagram is accurate for my solution. K&J doesn't have a 1/16th inch thick one-square-inch magnet with the poles in the proper orientation for N scale magnetic uncoupling, but the desired orientation is achieved by using two 1" x 1/2" x1/16" magnets with the poles on the long thin edge, side-by-side.

And yes, they make magnets strong enough to pull cars off the rails. I started with 1/8" thick and they were too powerful. As it is, the 1/16" thick magnets have to be buried 1/16" below the bottom of the ties to prevent cars with steel weights from being held in place.

[shark_jj]

thanks everyone, that is great information.  I will get some of these magnetics and give them a try.

[peteski]

Here is how I understand the magnetic poles need to be aligned for the magnetic uncoupling to work.



Since the magnetic field is weak between the poles (in the center of the magnet), the trip pins are attracted to the  poles.  I can't visualize how Bryan uses 2 magnets.

[C855B]

End-to-end with the poles oriented in the same direction, essentially making a 1/2" x 2" magnet. 1" is too small a target for reliable uncoupling.

[bbussey]

Here is how I understand the magnetic poles need to be aligned for the magnetic uncoupling to work.



Since the magnetic field is weak between the poles (in the center of the magnet), the trip pins are attracted to the  poles.  I can't visualize how Bryan uses 2 magnets.

Exactly the way you have it on the right, if you envision your red and blue to each be a 1" x ½" magnet.  The two magnets attract each other, and the N/S poles at the joint are negated.

End-to-end with the poles oriented in the same direction, essentially making a 1/2" x 2" magnet. 1" is too small a target for reliable uncoupling.

I tried 1/2" wide, it wasn't reliable.  The 1" x 1" magnet works perfectly, especially given that the K&J magnets are far more powerful than the magnets MTL uses for their above-ties uncoupler.

I'm using them mostly for motive-power changes on New Haven passenger consists.  But I also prefer the shorter magnets for delayed uncoupling.  Two-inch-long magnets make it more difficult to manipulate shorter cars (such as 33' twin hoppers) without additional uncouplings between adjacent cars.

[C855B]

OK, gotcha.

...  Two-inch-long magnets make it more difficult to manipulate shorter cars (such as 33' twin hoppers) without additional uncouplings between adjacent cars.

Interesting. I always have issues "hitting" the magnets. It could be that I'm not all that disciplined (yet) about making sure the couplers are working smoothly, and they need a little bit of bumping around to move.

[peteski]

Thanks for the explanation Bryan - now I get it.

[SP-Wolf]

So..... how do the Micro Trains between the rails magnets work? Since it appears to be a single magnet. are they actually two magnets in one-?

Thanks,
Wolf