Hiding the Uncoupling Magnet in Your Yard Tracks

Thanks for posting this GRJ...   I had saved a bunch of the old 027 tracks, but I never liked the other way of incorporating these with the red plastic core showing in the Gargraves, plus it just seemed like alot more work on the center rail .... Inverting it and installing a new core is a great idea.....

That looks great!!

Very Slick !

Nice!! Bookmarked this thread!!!!

John, cool post.  Years ago before TMCC and DCS I did something similar with my tinplate track.   I beat the bushes at every train show for old uncoupling tracks for the magnet and coil.  At one time I was able to buy new ones without the core.  Not a problem as the core was just 1/4 inch round steel.  I control them by good quality push buttons on my panels.  No Radio Shack buttons.  I have 92 of them on my layout and they all still function.  Great for breaking a train.  I hit the button to fire the car and then open the locomotive coil.

Very inventive solution.

Great work.

Alan

Looks like I'm going to be tearing the crap out of my layout!  I have been trying to come up with a hidden uncoupling magnet for years.  This is so simple and exactly what I've been looking for.  Thanks John and Harry!

Tom

My dad followed Harry's "how to" just last week and used his old UCS sections from years ago to put these uncouplers in all 5 new tracks going into the ice dock and brewery.

John,  Does the length of the core affect the strength of the magnet?  If not, I'm thinking of mounting the coils underneath the table top and extending the core up through the table top and roadbed.  This would only require cutting a small section of rail and drilling a 1/4" through hole.  This would make retrofitting them much easier as I wouldn't have to tear up a bunch of ballasted track.

Tom

I used the 027 uncoupling magnet years ago, like Marty; but, on Gargraves track.

I have two left that I didn't use--no track pieces attached.  If interested, let me know via email in my profile.

Cool ice dock.  

Very nicely done !!

Alex 

John, thanks for posting  and to Harry Henning for this novel solution.

That's really cool John. So low key, they are almost invisible.

Since all of my track is already in place, I've gone with an approach closer to Marty's. I keep the "eye" of the 027 uncoupler, but do paint it black to tone it down. I find the effect to be rather pleasant, and makes it easier to spot when switching. Here's a finished one.

This is how I start, by cutting away the center rail and two ties.

These still need paint and ballast.

Elliot, nice job.

Is there any type of electro magnet for this application that we could buy from Digi-Key or someplace?  Could take a long time to get old UCS tracks at train shows for a big layout.

Bill

That's a great idea John, thanks for sharing it!

Paul

Now that is cool John !    thank you  now I need them for Kadee's.      Clem

Clem, I was going to ask about a hour ago, but didn't want to feel like a fool. Do those work on Kadee's?

John thanks for sharing Harry's very inventive way of disguising the uncoupler.  I've seen approaches like Marty's and Elliot's and thought those were very good but Harry's approach makes them nearly invisible.

Thank you, Harry Henning, for a great idea and GRJohn for sharing it with clear explanations and photos.

mike g. posted:

Clem, I was going to ask about a hour ago, but didn't want to feel like a fool. Do those work on Kadee's?I've been

Mike, I don't think they will.. I've been 'playing around' with the regular uncouplers and they won't work with Kadees.. Kadees need to be moved to the side to uncouple.. If two of these can be fitted side by side, in between the rails, that 'should' work.. I'm going to experiment with that idea at some point.. Maybe someone else already has.. In theory it would work..

You could modify it to work with Kadees but you would need at least 1 of them on each side of the center rail. Having just one in the center won't pull the Kadees to the side to open them. For yard tracks your better off using super magnets and burying them in the ballast like was shown in another thread some time back.

Thanks for the information guy's. I was just wondering.

I have also used the magnets from the old 6019 uncouple tracks.    Cut out the magnet and splice it into my O-31 tubular track.  This magnet is on the mainline track.  The switch is the spur that goes to my 97 coal elevator.

I have also spliced in the control rails.  Here is the set up I have at my 97 Coal Elevator.   The uncouple magnet is placed before the control rails.  This way I can uncouple the dump car and leave it in position for unloading.

Still need to ballast the track.   Have been working on this area of my layout for the past few months.

Steve

Great idea!  This is an issue that has been holding up progress here for a while.

Marty Fitzhenry posted:

Elliot, nice job.

Thanks Marty. We've recently gone into mass production on these. The layout will have 74 magnets under the current plan. As operations commence, needs for additional magnets may be discovered.

That's a really neat idea. Makes then nearly invisible. Thanks for posting and thanks to Harry for coming up with the idea. Lots of very innovative folks around here with some great ideas. 

I know one won't work, and not sure if there is enough room for two side by side. or does it have to be longer not just a post. I want to use them on mainline so on/off switch is better. Oh well at least the Kadee magnets look like a small grade crossing.

Steve24944 posted:

I have also used the magnets from the old 6019 uncouple tracks.    Cut out the magnet and splice it into my O-31 tubular track.  This magnet is on the mainline track.  The switch is the spur that goes to my 97 coal elevator.

 

I have also spliced in the control rails.  Here is the set up I have at my 97 Coal Elevator.   The uncouple magnet is placed before the control rails.  This way I can uncouple the dump car and leave it in position for unloading.

 

 

Still need to ballast the track.   Have been working on this area of my layout for the past few months.

Steve

I like what you did with the coal loader.  Any info on this project?

Don

Don   -  Here is a link to a Forum Thread about 97 coal elevators.   My pictures are towards the bottom of the post.

Steve

https://ogrforum.ogaugerr.com/t...86#24378330517873886

Glad you folks liked it, I was quite impressed when Harry came up with it, and I thought it was worthy of sharing.  You can tell that Harry spends a lot of time thinking about trains.   I know many people have commented on how ugly they are undisguised.

As for lengthening the magnetic core affecting the operation, I can't honestly say, though I'd say that a bit more length probably wouldn't have a significant effect.  The best way to find out is to do a trial run and see what your results are.

EXCELLENT idea!  In the file for the new layout.

Thanks!

ogaugenut posted:

Is there any type of electro magnet for this application that we could buy from Digi-Key or someplace?  Could take a long time to get old UCS tracks at train shows for a big layout.

Bill

All really nice ideas!

I'll ask a REALLY basic question though....along the lines of Bill's question above...

Has anyone determined how many windings of magnet wire are on one of the Lionel cores?  

If not, I may sacrifice one to get the answer.

The reason I ask is that, seeing how simple and obscure John/Harry's idea is, it shouldn't be that hard to make electromagnet cores ourselves.  How hard could it be to come up with a supply of inexpensive spools? (a 3D molding '101' project??)  Magnet wire can be purchased in bulk.  1/4" dia. steel pegs?.....easy to come by.  A homemade winder/counter?.....why you could probably crank out a basic coil in a few minutes......without all the scrounging and salvaging.

OTOH, not taking away anything from the recycling aspects of their idea.  Lord knows there are a bazillion rusty, useless UCS relics around........something else to keep a sharp eye out for at the shows, eh what?  (Oh, good grief!  Now I've done it!......the price of junk is sure to skyrocket!)

KD

You're right, I'm sure it would be child's play to totally roll your own, there can't be that many windings on that coil.

If you want a coil form, consider plastic sewing machine bobbins, they're cheap and readily available.

 25 Pcs/Set Clear Bobbin Home Sewing Machine Plastic Spools Thread Brother Singer, $.99 or 4 cents each.

eBay: 401234325488

Last year, I had a button stick with a car directly over it and here is what I was greeted with when I came back from supper.  These things have a lot wire in the coil.

+ John, back in December 1991 in OGR run 120 I first showed my uncoupling magnet system and many of my friends followed what I did.  Run 120 was my first OGR cover story.  I was shocked when Fred Dole informed me he was going to put the story in word for word without having to edit a word.  I love what you did and all the guys.  I am still very happy these work great today as they did many years ago.   York was good to me for finding the parts needed.

Well I guess I have yet one more item to look for at York in April.

Thanks for sharing!

-Greg

Marty, an electric drill and a big spool of magnet wire.

John

Your Bobbin idea - a bobbin winder on a sewing machine.

Bill

Yep, not sure how your wife will take it.  I could probably get away with it, I'm the one that has to fix the sewing machine if it malfunctions.

Rather than a sewing machine, just use a drill motor, drill press or lathe to hold the bobbin. No need to count turns if you know the wire gauge and coil resistence. Get a spool or bobbin close to the UCS in dimension (OD, ID, Thickness) use a nut and bolt to secure the bobbin to your motor and fill it with wire. Number of turns or resistence is not critical. Close counts. More wire with added drive voltage will make a stronger magnet. All of the variables being equal the magnet's strength is approximately the current times the number of turns.

Anyone needing quantity this would be easier than cannibalizing UCS tracks.

Pete

Yes, had we thought of the bobbin idea, we'd have probably bought some.

Steve, your 97 looks fantastic.  I went to the old thread and there were a couple of really good looking camo jobs for the coal loader.

I made some measurements on a Realtrax UCS which might give some ballpark numbers.

Please check my math but here's my swag at # of turns:

The magnet wire is ~0.013".  At the core, the radius is 0.12".  At the outermost coil, the radius is 0.4".  So one "layer" of coil has (0.4 - 0.12) / 0.013 = 21 turns. The coil is 0.4" high so there 0.4 / 0.013 = 31 layers.  Hence about 600 turns.

I measured the coil at 5.3 ohms.  Let's assume 0.013" is AWG 28 or 65 ohms/1000 ft.  So that's about 80 feet of wire.

Try it the other way.  The average turn is at a radius of (0.4 + 0.12) / 2 = 0.26".  So the average turn has a circumference of 1.6" or requires 1.6" of wire.  80 feet = 960 inches.  960 inches at an average of 1.6" per turn = 960/1.6 = 600 turns. 

My estimate is 600 turns, requiring 80 feet of #28 magnet wire.

That eBay bobbin says: "Size: 12x10x2.4cm / 4.7x3.9x0.9inches".  4.7" seems like an enormous dimension for a UCS coil?

Keep the good ideas coming!

BTW, if the spools (e.g., sewing machine bobbins) were not the same size (diameter + depth) as the UCS spool, wouldn't a couple of the 'bobbin' coils stacked on a longer core give you more strength for the same voltage?  (Being sure, of course, you spliced the coils in series?) 

It would be interesting to have some experimentation with all of this to give some direction for the DIY-coil crowd.

Just saw an ad for a yarn bobbin.....3.5" in diameter!!  Fill that sucker with #28 magnet wire and your couplers will open for sure, for sure!

KD

That will work John.

I don't understand those bobbin dimensions.  These are from our Bernina sewing machine which I'm told would be similar to (though not the same) in dimension to other sewing machines.  Definitely not inches in diameter!  Would want a plastic or non-ferrous bobbin too.  I'd think two plastic disc could be drilled with the diameter of the steel pin core and glued into place eliminating the need for a bobbin.

John, I was blown away with all the wire in this coil.  

If you want to be precise with the length of the wire....I used to have my fishing reels wound at my local tackle shop. They had a counter with a spool on the end to measure the line as it went on the spool. Just wrap the wire around the spool before running it on to the bobbin. Would work perfectly for this project.

That looks like a handy tool but again there is no need for this level of precision. Consider that most of these USC tracks are powered by track voltage. They would work between 10 (maybe lower) and 20 volts. The magnetic strength will vary with voltage though usually not in a linear fashion due to saturation. The material you use for the core will have a much greater effect. The ideal material is soft iron (see ebay and science project suppliers). Other exotic materials are better but not worth the money and effort. Using a steel screw will reduce the field strength. Also extending the core much beyond the windings also reduces the magnetic force. How much to be determined.

I have a gaussmeter at work. If I get a chance I will try and make some measurements.

Pete

Like others have stated, the dimensions are bogus for the bobbin.   I took a Brother bobbin and measured it.

20mm in diameter, 12mm thick, and the inner core is 8mm in diameter.  This is very similar to the uncoupling magnet coil.

Tom Densel posted:

...Does the length of the core affect the strength of the magnet?  If not, I'm thinking of mounting the coils underneath the table top and extending the core up through the table top and roadbed.  This would only require cutting a small section of rail and drilling a 1/4" through hole.  This would make retrofitting them much easier as I wouldn't have to tear up a bunch of ballasted track.

How long would the "core" need to be to reach under your table?  As Norton points out, there are forces of nature involved.  The core is funneling or concentrating the field because the steel shank offers a magnetic path of lesser resistance than air.  But there are limits.

Anyway, some other thoughts about a DIY coil.  It appears on eBay it's about $1 for 100 feet of 28 magnet wire in small quantity (to wind a few coils).   But you might have or be able to find a different gauge cheaper.  As Norton also pointed out way back it starts with the so-called Amp-Turn product.  So if you hit a 5.3 ohm coil of 600 turns with 14V, that's about 2.6 Amps (=14/5.3) and you have an Amp-Turn product of 2.6A x 600 turns = 1500 Amp-Turns.  Within reason I could increase voltage 10% while decreasing the number of turns by 10% and achieve the same pulling force on the uncoupler.

Separately, there's the issue of over-heating or the dreaded melted uncoupler magnet.  This one also requires some DIY consideration.  You go directly to jail and don't collect $200 if you run 2 or 3 Amps of current through #28 wire.  I wonder why.  So heating power into a 5.3 ohm coil would be V x V / R = 14V x 14V / 5.3 ohms = 37 Watts.  OMG!   Is it any wonder you should only briefly hold down the Uncoupler button!

So back to original question on extending the core.  This would require some experimentation but safe to say you will need more Amp-Turns to achieve the same pulling power.  Practically speaking I think one would go to Home Depot and buy a 25 cent bolt of suitable dimension as opposed to finding some pin with a special alloy or whatever.  And you might only find, say, #26 wire at your store.  Then you can do the math with how to set the Amp-Turn product with different wire size which of course has different resistance.  The larger wire size means fewer Turns on a same-sized bobbin....offset by increased Amps because of the smaller per-foot wire resistance.

I don't know what all variations of bolts are out there but perhaps one could use the threaded portion in some clever way to assist mounting or to, say, screw on some plastic discs with threaded hole to serve as coil holders...

The cores are easy.  Home Depot.  Go to the metal section and buy a length of 1/4 rod.  You will get many cores out of the 6 foot length.

Gunrunner John, and everyone, these are great ideas, Thank You for this Thread...

I was just going to skip uncoupler magnets, but now this has got me thinking.  Perhaps it's time to research about making them and some experimentation.

You have seen a few variations in this post.  Pick what you like.  Not a lot of money involved.   I run a passenger only layout and back the trains into my 23 track terminal and hit the un coupler first to fire the car coupler then the engine electro coupler.  I then pull the engine out of the yard and back it down onto the turntable.  Whenever I want to bring another engine in the terminal and hook onto that train, the coupler on the car and engine are both open and everything (most of the time) comes together.  I have many couplers on my main line also.  I can leave a train on the main  and bring the engine  to the turntable.  I then bring out any engine I want to join that train.  

Having traveled to Pennsylvania and New York many times, my favorite operation was when we pulled into New Haven and the diesel left the train on the main.  The train went silent inside.  Next I would see a GG-1 sliding by us on the next track and it would hit the switches and back down and hook to our train.  After hookups were made we were off at instant speed.  I duplicate this often on the layout by using any one of my New Haven diesels or I-5 Hudson.   Steam/diesel to GG-1 or GG-1 to diesel/steam.  

If you have no need to uncouple cars, no big deal.  If you want to do any operation, give the un couplers a go.

Is there a better way we can do this?  With all the great minds we have on this site, I think we can.  Food for thought & discussion, could this be done inside the car by using track power to run the magnet and a sensor that could be turned on & off?  Just having some fun.

smilesrs posted:

...could this be done inside the car by using track power to run the magnet and a sensor that could be turned on & off? 

Not sure I understand your idea. 

Are you suggesting an active electro-mechanism in each car?  And the electro-mechanism is like an engine's operating coupler (spring-loaded solenoid)?  Do you see each car having powered-trucks to get track power or have some idea on how to daisy-chain track power from car-to-car such as disguised steam-brake lines or whatever?  What is the "sensor" sensing?

Might as well just equip every car with a TMCC dummy locomotive module and electrocouplers, problem solved.  It's probably just as cheap, and I'm 100% sure that it'll work.

I read all this and ran out and bought me an uncoupling track and a operating/uncoupling track.     Wait.   I don't have any operating cars?  I thought I had an ACME gondola with the coyote and roadrunner ..   I got it out of the box and it works off of gears driven by the axle.  ..   HA   

Jim

The "operating" (4th/5th rail) part of operating/uncoupling track sections reminds me of a recent thread where a guy proposed activating his operating cars using the uncoupler magnet.  IIRC there were clearance issues with the slider pickups to the 4th/5th rails.  The idea was to place a magnetic sensor in the car, position car over the uncoupler coil, then activate car by pressing "uncouple" instead of "unload". 

Perhaps the less obtrusive appearance of these coils whether modified or DIY would make it more palatable to put more of them around a layout.  For example, the inconveniently located on/off switch (under the chassis) for passenger car lights could be replaced with a magnetic sensor.  Position car over an uncoupler coil to toggle lights on/off. 

Steve-short answer not worth it.  Do what John and others outlined and be done.   Why fix something that is not broken.  Anything can be done limited by your wallet.  I have had my uncoupling magnets in the layout from around 1984.  They all work perfect.

I "rolled my own" many years ago to use with Gargraves track.  Just make sure you use the same gauge electromagnet wire and number of turns that Lionel used originally or the flux generated will not do the job.

I was about to use Atlas "O" uncouplers this time, but this thread has inspired me to do it the "old" way again.

Thank you Gunrunner John!

Hal

We just used Gargraves uncoupler sections, having way too many other issues to resolve, and not intending to build a "scale perfect" layout, we opted for the functionality and ease of installing the "stock" uncouplers.  Have to say your method sure looks good hidden.

stan2004 posted:

Tom Densel posted:

...Does the length of the core affect the strength of the magnet?  If not, I'm thinking of mounting the coils underneath the table top and extending the core up through the table top and roadbed.  This would only require cutting a small section of rail and drilling a 1/4" through hole.  This would make retrofitting them much easier as I wouldn't have to tear up a bunch of ballasted track.

How long would the "core" need to be to reach under your table?  As Norton points out, there are forces of nature involved.  The core is funneling or concentrating the field because the steel shank offers a magnetic path of lesser resistance than air.  But there are limits.

Anyway, some other thoughts about a DIY coil.  It appears on eBay it's about $1 for 100 feet of 28 magnet wire in small quantity (to wind a few coils).   But you might have or be able to find a different gauge cheaper.  As Norton also pointed out way back it starts with the so-called Amp-Turn product.  So if you hit a 5.3 ohm coil of 600 turns with 14V, that's about 2.6 Amps (=14/5.3) and you have an Amp-Turn product of 2.6A x 600 turns = 1500 Amp-Turns.  Within reason I could increase voltage 10% while decreasing the number of turns by 10% and achieve the same pulling force on the uncoupler.

Separately, there's the issue of over-heating or the dreaded melted uncoupler magnet.  This one also requires some DIY consideration.  You go directly to jail and don't collect $200 if you run 2 or 3 Amps of current through #28 wire.  I wonder why.  So heating power into a 5.3 ohm coil would be V x V / R = 14V x 14V / 5.3 ohms = 37 Watts.  OMG!   Is it any wonder you should only briefly hold down the Uncoupler button!

So back to original question on extending the core.  This would require some experimentation but safe to say you will need more Amp-Turns to achieve the same pulling power.  Practically speaking I think one would go to Home Depot and buy a 25 cent bolt of suitable dimension as opposed to finding some pin with a special alloy or whatever.  And you might only find, say, #26 wire at your store.  Then you can do the math with how to set the Amp-Turn product with different wire size which of course has different resistance.  The larger wire size means fewer Turns on a same-sized bobbin....offset by increased Amps because of the smaller per-foot wire resistance.

I don't know what all variations of bolts are out there but perhaps one could use the threaded portion in some clever way to assist mounting or to, say, screw on some plastic discs with threaded hole to serve as coil holders...

To add to this thought - Home Depot item - #10-(7/32") diameter center hole nylon washers -  for the threaded portion of the bolt for the core winding- twist it on

edited for #10  washer which should screw on to a 1/4" bolt

Look up Janome plastic bobbins,

Is anyone seriously trying to roll-their-own uncoupling coil?  If so, post where you are and we can compare notes.  My objective is to completely fit the electromagnet in the cavity of a Realtrax section so you don't have to drill into the base of the layout to extend the core length.  There are many electrical and mechanical considerations but I assumed I was the only one pondering this (the thread went cold) so haven't bothered to post any additional thoughts...

The Home Depot nylon washer is a great find...but is 1/8" thick which takes precious height away if trying to fit the entire "bobbin" in the ~1/4" available height under a section of Realtrax.  Same applies to sewing machine bobbins.

Stan,

I am building a layout now with a friend. We need about 8-10 uncouplers under or in Gargraves track. I wanted to experiment under table core mounting with the extended core. We have 1/2" OSB and 1/2" ceiling tiles + the 7/16" or railhead height.

I don't anticipate it to work. So, rolling our own and installing using NPOG's method may be the answer.

I was concerned about plastic melting easily.

I'll speak to him about his desired mounting method. I may be able to experiment with your objective in mind as it would provide a cleaner install on the Gargraves track.

Trust me, the extended core didn't affect the uncoupling strength, those uncouplers work great in the yards.   The only messy part is having the coil below the level of the table, but drill a hole and you're all set.

stan2004 posted:

Is anyone seriously trying to roll-their-own uncoupling coil?  If so, post where you are and we can compare notes.  My objective is to completely fit the electromagnet in the cavity of a Realtrax section so you don't have to drill into the base of the layout to extend the core length.  There are many electrical and mechanical considerations but I assumed I was the only one pondering this (the thread went cold) so haven't bothered to post any additional thoughts...

The Home Depot nylon washer is a great find...but is 1/8" thick which takes precious height away if trying to fit the entire "bobbin" in the ~1/4" available height under a section of Realtrax.  Same applies to sewing machine bobbins.

Stan,

the washer is .032 thick, so it's only a 1/16th for 2 of them. I changed the washer to a 7/32 hole version . 3/8" dia.

You have to order for store pickup.

I had a piece or two of RealTrax. I'll have to find it.

Right.  The Realtrax scenario is definitely a "size matters" situation.  After mess around with this a bit, my next step was going to be to wind the coil on a bobbin that had remove-able end-caps (or washers in this case) and figure out a way to apply glue or whatever.  Thus the coil would have no thickness from the bobbin end-caps.

Anyway, in your scenario what is the length/diameter of the steel rod core and how tall/thick is your coil (placed at the far end of the rod)?  I'm sure there are fancy electromagnetic simulation programs which can figure these things out but for us mere mortals I might be able to jury up a simple test to measure the loss of magnetic pulling force with an extended core.  I have a magnetic probe that can measure field strength so I can cobble together a simple fixture to confirm you're in the realm of reality.

stan2004 posted:

Right.  The Realtrax scenario is definitely a "size matters" situation.  After mess around with this a bit, my next step was going to be to wind the coil on a bobbin that had remove-able end-caps (or washers in this case) and figure out a way to apply glue or whatever.  Thus the coil would have no thickness from the bobbin end-caps.

Anyway, in your scenario what is the length/diameter of the steel rod core and how tall/thick is your coil (placed at the far end of the rod)?  I'm sure there are fancy electromagnetic simulation programs which can figure these things out but for us mere mortals I might be able to jury up a simple test to measure the loss of magnetic pulling force with an extended core.  I have a magnetic probe that can measure field strength so I can cobble together a simple fixture to confirm you're in the realm of reality.

The longest would be - 1 7/16" extended out of the core + the .4 of a 600 wrap core. That like an 1 7/8" total, yes?

it also look like the insulating varnish is mail order only.

What were you going to do to reduce the depth? Make a larger diameter?

Moonman posted:

...What were you going to do to reduce the depth? Make a larger diameter?

This is definitely a work-in-progress.  The mechanical/space fit is non-negotiable in my mind.  I'm of the mind there's a rapid drop in effectiveness of the outer windings as diameter increases.  I'm thinking it will involve some electronic intervention...possibly involving a DC supply voltage, possibly some type of capacitive charging, who knows.  I know there are a few guys that use DC but they are few and far between.  But the point is the existing AC coils created a half-wave rectified sine wave pulling field.  This is where I think there's opportunity for fiddling.

The existing Realtrax coil is about 0.4" high.  If I only have 0.25" in the cavity, that's quite the deficit but it's less than a doubling.  So between picking up, say 40% from capturing the peak voltage (using some kind of capacitor charging), and requiring the uncoupling supply to run up to 20V AC rather than, say, 14V AC accessory voltage, I think I can get it back.  If operating at higher voltages, the electronic solution would include power limiting to prevent over-heating.  So there are a variety of ideas that are not expensive - especially considering the price of an off-the-shelf Realtrax UCS with the unsightly 4th/5th rails for the Unload function which I'm not interested in.  After all, per the theme of this thread, what's the point of hiding the uncoupling magnet only to make the 4th/5th Unload rails that much more obvious!

I even stocked up on rare-earth Nd magnet cylinder/rods ~1/4" diameter in a probably mis-guided attempt to create a pre-biased core.  In practice this magnet cylinder would be placed "in series" with the extended core.  In other words there's a constant DC field of, say, 25% of the force required to uncouple at all times.  Then when activated, 25% fewer Amp-Turns (in my naive way of thinking) is required to generate the required uncoupling force.

Moonman posted:

...

The longest would be - 1 7/16" extended out of the core + the .4 of a 600 wrap core. That like an 1 7/8" total, yes?

I was thinking about your situation so here's a bolt that extends out about 1-7/16" as you specified.  I measured the field strength above the top of the bolt.  The probe was placed 1/8" above the bolt to simulate the distance from the top of the center rail to a car's uncoupler disc.  I slid the coil up and down the bolt to see how the pulling force varied. Relative to the coil being flush to the top of the bolt, the field strength dropped in a roughly straight line down to about 25% when the coil was at the bottom.  This could be a problem! 

Stan, your bolt looks a lot longer than our design.  In the one I presented, the length past the coil is less than 1/2".  I can readily see that 1.5" would be pushing things a lot.  As Marty previously posted, there's a lot of wire on those coils, is your 300 turns an accurate representation of the actual coil?  Perhaps with a long bolt, you need more turns and/or heavier wire to give you more ampere turns for more magnetic field strength.

The issue I was addressing was Moonman's previously stated idea of mounting the coil completely under the layout and just running the narrower diameter core up to the track.  In his words, "We have 1/2" OSB and 1/2" ceiling tiles + the 7/16" or railhead height."  I would think it much easier to drill just a 1/4" hole for a steel rod...vs. 1" holes or cavities to place the coil higher/closer to the rail top.

The other take-away, perhaps obvious, is you want to place the top of the core as high as possible.  The drop off in magnetic field strength through air is profound for this application.  As mentioned I measured the field strength about 1/8" above the bolt.  If you double the gap to 1/4", that extra 1/8" cuts the strength about in half! 

As to the coil configuration, I realize whatever Moonman does will be different from what I am messing with for a DIY Realtrax section where the coil height is constrained to completely fit in the cavity under a track section.  OK, perhaps there is nothing new here...I thought I was doing my good deed for the day. 

That's why we put the core level with the center rail.  I always hated the projecting coil on many decoupling tracks, having it level with the rails is almost as close and works well.

As for your Realtrax idea, seeing the ugly one that MTH makes, I can understand why you'd want to improve on it.

Thank you, Stan.

I have been lumberjacking and finishing yard work. There were two big wind storms in our area , one in the fall and one in the spring that created a tree mess. I finally decided to get it done. Not fun stuff, you know.

Anyway, I didn't get further than acquiring the materials.

Your testing tells me at least I can burying the coil in the ceiling tile which is easy carving and have the bolt only up through the track.

You have a nice looking track now.

Our coil is just below the ties on the Gargraves or Atlas track, and it works very well, so I suspect you should have no issues with the same configuration.

Does anybody have anything new to report?

Any new experiments that proved successful?

Anything that was tried and didn't work?

Get rid of the un coupling track sections all together.Since nobody can make couplers that don't blow open and we have to tie strap or super glue them shut, what good are they.

Reading through many topics and came upon this one. I'm curious if anyone has finished any "home grown" uncoupling  magnets and what their results yielded.

@spudder posted:

Reading through many topics and came upon this one. I'm curious if anyone has finished any "home grown" uncoupling  magnets and what their results yielded.

I can only surmise you didn't actually read my thread starting posts, we have a bunch of them in the yard tracks at Harry's place.

John, I read all the posts. Using the Lionel parts works really well and is the best solution using an item that is readily available. As this thread evolved, people were talking about making their own magnets. You offered the suggestion of using thread bobbits....a cool idea. I was wondering about these home brewed electro magnets. I should have made my self more clear.

Well, since we just salvaged the O27 track magnets, we just added the core.  However, winding the same number of windings on a bobbin, or any other similar sized spool, with the same number of turns and wire size would almost surely work just as well, it's simple electronics.  If I put the same number of ampere turns in the same size coil, I'm going to get the same magnetic force.  The only reason I never tried it is there was a pile of rusty O27 uncoupling tracks available.

@gunrunnerjohn posted:

Many folks struggle with hiding the uncoupling magnet in their yards, usually the uncoupling tracks are fairly ugly and really stand out.  Wouldn't it be nice if you could make all your uncoupling tracks look like this.

This is how the uncoupling tracks were done on the NPOG layout.  Credit Harry Henning for coming up with this nifty idea.

The obvious question comes up, where is it?  You may need a signal post to indicate where to uncouple cars!  Let's examine how this was done.  You start with all those ugly 027 uncoupling tracks you were about to throw out...

Cut the magnet free on each side.

Remove it from the track, being careful not to break the wires.

Cut the wire fee, you can discard that old track you were about to throw out anyway.

Here's the magnet coil with the core removed.

Separate the coil from the rest of the metal from the track.

Cut a proper diameter bolt shank to length to extend the magnetic core.

Insert your core into the coil and glue it.

Glue the assembly to the bottom of the track after cutting a slot in the track, see following shot.  Jumper around the cut track to maintain conductivity.  You will need a hole to insert the magnet into in the benchwork, conveniently, that's where you'll run the wires from the magnet.

Install the track with the magnet.

Apply some ballast and it's hidden.  Wire up the decoupling magnet circuit and you have a hidden decoupler.

I hope this is useful to someone out there.

Nice job John, I have always used a long screw and winding wire around the shaft. Painted black poof like yours its gone.

That  @gunrunnerjohn  is something else as he always has a few great tricks up his sleeve!

Honestly John you should write a book on the various tricks you have devised.  It would be a great seller.

Guys,

Thanks for reviving this thread! I was about to go searching for it when I found it a the top of my Forum page. Very timely!

Chris

LVHR

For those who don't want to change the core, the original coils can be somewhat hidden as well.

My bench top is 1/2" ply, I didn't want to drill through and then have to support the coil from below.

@Allegheny posted:

That  @gunrunnerjohn  is something else as he always has a few great tricks up his sleeve!

Honestly John you should write a book on the various tricks you have devised.  It would be a great seller.

Well, this one was actually the brainchild of Harry Henning III, I tagged along later.  I just figured it was worth posting here as it was a really clever solution to the issue.