Problem with Gargraves Uncoupling Sections

I had a similiar problem, but with Atlas uncoupling track.  Turns out it was not the uncoupling track.  The problem was the "thumb tack" on the coupler on some of my MTH cars was not being pulled down by the magnet.  Even sanding the finish off the "thumb tack" did not help.  The only cure was replacing what MTH calls the "armature assembly", which is the thumb tack, spring and plastic washer. The new "thumb tack" assembly, once replaced, worked like a charm.  Must have been a run of non magnetic metal, as I have replaced a few already.

Frequently this situation is the result of the thumb tack not being low enough to be "grabbed" by the magnetism of the uncoupler. On the other hand, I have a couple of cars whose thumb tacks are too low, and they are not pulled down far enough to allow the knuckle pin to release. My 3rd Rail Harriman coaches' thumb tacks are too high, thus aren't influenced by an uncoupling magnet, but this isn't a concern since the only time the cars are uncoupled is when they're removed from the track.

I spoke to Gargraves this AM; they told me that more recently manufactured uncouplers have a metal piece under the magnet to increase field strength.  According to the gentleman to whom I spoke, "it is amazing how well it works".  He is sending me 17 parts to place under the uncouplers (an odious task since they are ballasted in, however, if it works, it will be worth it.  Thanks for the hints; I will appreciate any other thoughts as I am not yet convinced that the metal insert will solve the problem - when I install one and test it, I will report the results here!

I wonder if you could reach the bottom by cutting a hole in the bench and not rip up the tracks to fix them?

The Gargraves rep suggested that if I could lift the track slightly, I could slip it in place (he said it is only ~ 0.025" thick).  While I will have to remove some ballast, I suspect this will be the easiest solution.  Thanks, Var

Var,

Are the cars  that the uncoupler does not work on all of the same make and do they have the same trucks and uncoupler tabs? Do they work on some uncouplers and not others? This would help narrow down the problem. For the ones that do not work, I would suggest trying to open the coupler by depressing the tab or thumbtack by hand. Does it release easily? If not, perhaps an application of graphite to the working parts might improve the couplers operation.  Some couplers are just stiff and need to be freed-up

Hey Gunrunnerjohn:  while waiting for the parts to arrive from Gargraves, I have been thinking about how to lift the track, etc.  The more that I think about it, the better your idea looks (particularly since many of the uncoupling sections are hard to reach).  The problem that I now consider is how to cut through the 3/4" plywood without hitting the uncoupling section?  There are a lot of wires surrounding these parts (turnouts, etc.) so there really isn't room for a router.  Any suggestions re how to cut through without mangling everything?  Thanks, Var

Interesting question. Is the track on a roadbed of some kind, or is there foam on top of the plywood?  If so, I think I'd probably use a Forstner bit on a drill to just cut through the plywood.  If you're careful, you can just cut the plywood and not go beyond.  The center tip extends slightly, so that's why you need some sort of spacing between the plywood and the track.  In case you don't know, the Forstner bit is used to drill flat bottom blind holes.

Thought this might help.

Thanks Charlie, I should have posted a picture.

An interesting suggestion; the parts are ~ 0.75" x 2" from inspection of the bottom of an as yet unistalled uncoupler.  I suppose I could drill a chain of wholes  with a 1" Forstner bit, but suspect that would be tricky.  Any thoughts about a dremel tool bit or some other alternative?  Your suggestion is the best idea I can conceive so I am by no means discounting it.  Thanks, Var

PS some of the uncouplers are on track that is on roadbed, but the yard track, where most of the uncouplers lie, is not.  This presents an additional challenge

Thanks, I will check the couplers and use graphite where appropriate.

You can get larger Forstner bits, you should be able to do it with a 2" bit and hit the mark.

OK, thanks!

Started checking into this uncoupling issue 2 years ago, I use the older round version on the Gargrave uncoupler. What was interesting is that some of the cars having the Delran plastic uncouplers would work and others would not, same manufacturer. I held a small piece of scrap carbon steel above the uncoupler a distance of approximately 1/8in, pressed the plunger switch to activate the coil and the steel was pulled toward the uncoupler, this indicates the uncoupler was operating normally. I started checking the plastic uncouplers and found the following combinations/issues, the plastic couplers being molded were not necessary straight and parallel with the track, the plastic centering tab on the coupler shank was attached and cracked(Verical crack line) or missing, the thumbtacks are not perpendicular to the rail and finally some thumbtack stems had to be shimmed. I used .120inch thick Plastruct shims and had to cutoff the pointed ends of the thumbtacks and hammer the head of the thumbtack flat. The Delran thumbtack seat must be lightly sanded to scuff the surface, the shims are glued to this seat using Gorilla Super Glue Impact-Tough Formula. Do not glue the thumbtack to the shim, after the shim to seat sets and hardens check the unglued side for flatness, if inclined/pitched sand flat and also make sure the head of the thumbtack is hammered flat, if the shim and thumbtack are flat glue them together. It the centering tab is not cracked, remove the uncoupling lever from the coupler shank, put the shank vertically in a machinists vise and check for straightness. If not straight, heat the shank judiciously and quickly using a heat gun to soften the plastic for straightening, is the uncoupling lever vertical pin that secures the knuckle closed does not fully engage heat the lever and bend for full engagement, the stem and thumbtack may also not be straight and perpendicular to the rail, heat and bend as required. The final issue is the most time comsuming, if the centering tab on the coupler shank is broken the knuckle will not open, this centering tab is replaced with a .015in steel spring. These springs are wedge shaped, on leg horizontal that bears in the beveled edge on the coupler, the inclined leg bears against the inside wall of the coupler on the pin side. Do not remove the swaged couple pin that holds the knuckle to the coupler body. You will have to custom make these springs, using a needle nose plier and harded wire cutter.  

Wow!!!

On a related note, we picked up the package from Gargraves today in the mailbox.  I did an experiment with one of the yet to be installed uncouplers:  I put a short section of track front and back, placed two cars on the track, and tried the uncoupler as-is; did not work (18 volts applied).  Next, I applied the metal strip sent to me by Gargraves - the result was amazing; a strong magnetic field that immediately uncoupled the two cars.  This was also done at 18 volts; I then tried backing off on the voltage to 16 volts and no soap.  So, the combination of the metal backing and a large (to me) accessory voltage appears to make it work.  I plan to discuss this with Gargraves tomorrow to get their reaction; stay tuned