Permanent uncoupling magnets

[Dayliner]

So I spent most of the afternoon installing a Kadee permanent uncoupling magnet under one of my spurs: removing track and roadbed, chiselling out a hole in the subroadbed, and putting everything back together. Only problem is, it doesn't work, or it works sporadically at best. Sometimes the cars will uncouple, sometimes (most of the time) they won't. The couplers do move when they pass over the magnet, but they do not disengage, so I am assuming it is a coupler problem and not a magnet problem. Will a shot of Grease-em do the trick?

[mgruber]

Which magnet are you using?

[rrinker]

Are you using the under the track magnet? That thing is so strong it will stick any cars that have magnetic axles. The ones meant for above the track mounting will not work under the track.
Also, are all your 'air hoses' adjusted properly? If you don;t have one, you NEED a couple height gauge. One of the functions it does besides the height of the knuckle itself is the height of the air hose. Too high and it won't be properly or reliably triggered by the magnet. Too low and it will snage on turnouts.
I've been experimenting with some alternatives, as the huge Kadee magnets leave alarge area where accidently uncouplings can occur. I found the little round magnets from Radio Shack work quite well - the ones that come in packs of 5. One under each rail, slightly in from being centered under the rail, but NOT touching, seems to work quite well. Coupler brand matters - Kadees and ones with pivoting knuckles seem to work fine, the split type like Accu-mates are JUNK. Don't waste your time. I have the same problem mechanically uncoupling with a pick (actually a bamboo skewer with a flat filed on one point). Kadee couplers work GREAT, I can ALWAYS uncouple them. The other brands - unreliable at best. Any stock I have that came with another brand of knuckle coupler I am gradually replacing with Kadee. Those that came with horn-hooks got Kadees back when i assembled them.

--Randy

[cwclark]

I think thaty's your problem as randy stated..the coupler hoses need adjusting...the magnet won't work unless the coupler hoses are close enough for the magnetic field to grab hold of them and separate the couplers...a kadee coupler height gauge and a pair of kadee coupler hose pliers should do the trick...Chuck

[Dayliner]

Thanks for the suggestions--it's good to know that I don't have to rip up the spur and start again. I'll be checking all my couplers now.

I'm using the #308, definitely under-track, but forgot to mention that I'm working in N--this shouldn't make a difference, though.

I agree with you Randy--everything gets Micro-Trains (in my case) trucks and couplers before it goes into service.

[rrinker]

Just make sure you have the 308 magnet centered under the track! It's probably more critical for N than for HO due to the track width. Those magnets are all polarized down the middle, meaning the center line is the dividing point between the north and south pole. If the magnet is off center, both air hoses will 'see' the same magnet polarity and move the same way, and thus NOT uncouple or move to the delay position.

--Randy

[Dayliner]

QUOTE: If the magnet is off center, both air hoses will 'see' the same magnet polarity and move the same way, and thus NOT uncouple or move to the delay position.

Thanks, rrinker, it looks like you diagnosed the problem correctly. I took another look at the installation and found that the magnet was slightly off-centre; not much, but enough to make a difference. I was able to re-lay the track and performance has improved considerably. I also found an article in last June's MR which suggested using Radio Shack ceramic magnets as an alternative to commercial under-the-track magnets in N scale, so I will probably be giving them a try.

[rrinker]

I am trying the RS magnets on my HO layout, and they work great. Should not be a problem for N. Of course, you have to be a bit more precise in where you stop the train, theres only a very small area where the magnetic field is just right to operate the couplers, but if it's big enough in HO then it certainly should work in N. Sure beats those huge 308 magnets - that's a big area for accidently uncoupling in HO, so it must be like a football field length in N. Considering the very same magnet works all the way up to O scale, no wonder.

--Randy

[Dayliner]

QUOTE: so it must be like a football field length in N

"One size fits all!" It's almost a whole car-length in N. Thanks to your encouragement, I will definitely be trying the RS magnets.

[CharlieBedard]

Randy,

A quick question on using the Radio Shack magnets since I would like to try them.

I've seen the MR article on using them in N scale. I'm in HO and I'm not sure if they are strong enough to work when placed under the rails (as you say) AND under the ties. Is that how you've placed them? Under the rails and ties and into the roadbed?

Charlie

[rrinker]

Just under the rails. I cut away a pair of ties so they fit up under the rail.

Although - having a solid piece of iron to back them and they seem to work throught he ties, just a lot hard to install. Also in testing I found if you double them up, they work through the ties.

--Randy