I have several questions about hands free uncoupling, specifically in HO scale with equipment using Kadee knuckle couplers. If it would be more appropriate to post this in the general Model Railroading Forum, I beg forgiveness.
I have used the Kadee old style electromagnet (between ties) and 308 (beneath ties permanent magnet) and 321 (between ties) and am pretty familiar with their pros and cons. After a hiatus of over 25 years, I am building a small layout and have become interested in neodymium magnets. There are several videos on Youtube concerning these magnets, but there are a couple questions still unresolved in my mind.
Both cylindrical and cube magnets are used in the videos. Seems to me the cubes (mounted between and level with ties) would be the easiest to mount and disguise. Any comments from users of these devices?
None of the videos address false uncouplings. I know from my experence with the Kadee B308 (under tie) that permanent magnets are prone to false uncouplings (uncouplings when NOT desired). Since I am using all non-magnetic wheels and axles in my cars’ trucks (is that an oxymoron?), will the neodymium magnets also be prone to false uncouplings? I was thinking they might not be as prone to this if only one or two pairs of magnets are used.
Andy Sperandeo long ago (early 1990’s) told me about another manufacturer of electromagnetic uncouplers, but I can’t recall the name. Anyone know? Are they still in business?
Any comments on the newer Kadee 308 (beneath ties) electromagnetic uncoupler vs. the older between the ties electromagnetic uncoupler?
Thanx for reading this and I look forward to your comments.
I used to be a big fan of magnetic uncoupling, and to a lesser extent I still use them. As a teenager back in the Kennedy and Johnson administration, I built my layout with ramp-style horn-hook uncouplers, and I even had a magnetic version that would raise the ramp on command. I just hated the idea of the Hand of God reaching down to do things on the layout.
In theory, my layout could still work that way, but once I started using bamboo skewers and realising that I could uncouple cars where I wanted to, and not just where I’d installed magnets, I became happier.
I have a number of between-the-rails magnets and under-the-track ones as well. I have a few electromagnet units on the main lines where spurious uncouple is very undesireable, too. All of these work as expected.
But, well, nothing beats a bamboo skewer. And this is from a guy who never wants to touch the trains.
One thing to keep in mind about the small rare earth magnets is there has been discussion about banning them from consumer sale because of the issue of kids swallowing them. I know, nithing to do with model RRing, unless you’ve planned your layout around them and suddenly they’re unobtanium.
Of course, they’ve been discussing this for several years now, so who knows? But if you go this route, you might lay in a stock of enough to take care of your needs, as there may not be another chance in the more distant future.
Using small but powerful magnets will reduce false uncouplings, because the working area is much smaller than the larger kadee magnets. It won;t eliminate false uncouplings entirely - if the slack goes in as the couplers pass the magnet they will open up just as surely as if they ran over a Kadee magnet.
I use skewers - as such I don;t adjust the Kadee pins other than the make sure they are well above minimum height. Few of my cars would work over magnets since the pins are too high. I just can’t bring myself to cut them off - most of them I’ve gone through and painted oily black with a dab of silver on the very tip to make them look more like air hoses.
I wouldn’t think the cubes small enough to fit between the ties would have enough potentency to do the job. I could be wrong, because I never tested those.
I have been finding on more and more of the many layouts our OPs Group run on as the Layout Owners replace the wheels with metal free rolling wheels
Is THAT!
When using the magnets beteen the rails - the cars get pulled together by the super magnets due to the metal weights and the extreme free rolling ability of the metal wheels.
I had one trying to pull a string of empty 2 bay hoppers out of a yard and they had to pass over a perm magnet.
EVERY Car in the train uncoupled as we tried to pull out of the yard track - we could see the magnet pull whole string forward and then uncouple so smooth -
fustrating to say the least!
The Layout Owner was totally amaized that this was happening when we called him over to see it.
We kept wishing the magnets were any place but on that layout!
THAT will never happen on my layout as we ONLY uncouple with sticks!
Thanx for the links. The concept of having each car and/loco equipt with remote uncouplers is not the solution for me. If I was using DCC it might be, but I’m not a DCC guy.
Also, the use of skewers or other devices to manually uncouple cars is not a solution for me either. My last layout was a walk around/in design and would have been suitable for manual uncoupling, but this layout is an island design that will use a central control panel, and “on-site” uncoupling is not feasible.
As for cubes vs. cylinder rare earth magnets - both geometry are used in the Youtube videos, and both seemed to work. These little magnets are suprisingly strong. That said, I am curious as to the relative performance of cube vs cylider as a function of how many magnets used and ease of installation (also if false uncouplings are different for each).
Bob, thanx for the info. Do the layouts that have issues use multiple magnets at each uncoupler site? Do the cars have non-magnetic wheels & axles?
I know these little magnets are strong. One fella that posted to Youtube has adjacent tracks (maybe 2" between them) that have these magnets mounted in the same location in each track (the magnets are next to each other, physically separated by about 2"). When he installed the magnets he didn’t install them considering their relative polarities, and the magnets (on the adjacent track) interacted enough to render them inoperable. He reversed on set of magnets’ polarity and all was well.
In each video on Youtube there were 8 magnets used (4 under each rail, or between ties near each rail). There was one guy that only used one magnet on each side of track (and it worked). So I was curious about the relative false uncoupling between using multiple pairs of magnets vs just one pair.
Thought I had a picture but I don’t, on my old layout I tried small button magnets, not even the rare earth type, just ordinary buttons from Radio Shack. I put them near the turnout end of a siding, one approximately under each rail, and they worked fine - the actual area where the couplers would open was very small so you had to spot accurately - not difficult without ballast at the time. Those were the only magnets on that layout, as I discovered skewers and that was that.
I have some of the small 1/8" diameter x 1/2" long ‘super’ magnets and placed just one magnet on each side between two ties and next to the rail. I just drilled 1/8" diameter holes and pushed the magnets down until they were flush with the top of the ties; no glue used so far. Just make sure they are inserted with opposite poles on each side. They work really well and yes they have a narrow ‘window’ of operation but I haven’t had any problem with unintentional uncoupling. I have several of the Kadee perm/mag uncoupling ‘plates’ burried under the track (actually replaces the cork in that area) and find that they are too strong and hold cars trucks directly over them (ones with metal wheels).
I plan to use the small cylindrical ones from now on. I will just mark the ballast or put a marker where the magnets are located so I know where to stop to uncouple. Sorry I don’t have any photos to post but will try to take some and post tomorrow.
The orientation of magnets is an issue when uncoupling. Kadee magnets are made with the north and south poles along the long sides not on the ends. This way the magnet pulls the coulpers apart. Many rare earth magnets, while they will hold a locomotive off of the ground, will not uncouple scale trains since the north and south poles are not oriented to the work that needs to be done.
They cannot outlaw rare earth magnets, you want some you take apart some speakers or some hard drives and you can have all of the magnets you want.
LION had opposite problem with layout of him (once upon a time before him used nothign but drawbars). Him could stop train on magnet and the engines were so slow and smooth that they would not uncoupple. LION builded a “Cutting Key”. On NYCT the cutting key operated the electornic controls that released the transit type couplers. ON route of LION, it was just a momentary reversing switch, activated so briefly that you would not notice it in the movement of the train or locomotive, but it was enough to provide a sure uncoupling.
Obviously you do not install uncouplers on the mane lion.
