# When Kato Couplers Don't Couple



## pmcgurin (Sep 7, 2010)

I have found that when Kato couplers don't couple with Kato couplers the reason is usually that one of the two couplers concerned has worn or a part of the coupler has broken off. one or both couplers need to be replaced. Kato makes packs of spares in black, part 11-702. Also in gray, unknown oart no. I threw the tag away, but they are on ebay. I bought some gray couplers recently.

Part of the coupler face seems to wear away.


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## vette-kid (May 2, 2020)

That's why I just switch them to MTLs and never worry about them again. Couplers are Katos Achilles heel. I'm pretty much a kato fan boy, but the couplers... ugh. 

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## pmcgurin (Sep 7, 2010)

You never have MTL couplers that won't couple with other MTL couplers? I have about 30% of the freight car couplers I have converted to MTL trucks that won't couple with other cars with MTL trucks and couplers. I replaced two of these trucks with two new ones I had on hand, and that fixed those. I don't know what the cause of this is, but I am hoping that portions of the couplers don't wear away or break away. It has been about fifteen years since I converted the freight cars to MTL, but the cars were stored for the last twelve years. The cars were gently treated, because all these small parts look delicate. I have a number of MTL cars and they sometimes won't couple with each other. I think I am going to have to do the same kind of maintenance on MTL trucks as I am doing now on the Kato cars, and the repairs to MTL trucks and couplers will cost more than the Kato couplers.


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## traction fan (Oct 5, 2014)

pmcgurin said:


> You never have MTL couplers that won't couple with other MTL couplers? I have about 30% of the freight car couplers I have converted to MTL trucks that won't couple with other cars with MTL trucks and couplers. I replaced two of these trucks with two new ones I had on hand, and that fixed those. I don't know what the cause of this is, but I am hoping that portions of the couplers don't wear away or break away. It has been about fifteen years since I converted the freight cars to MTL, but the cars were stored for the last twelve years. The cars were gently treated, because all these small parts look delicate. I have a number of MTL cars and they sometimes won't couple with each other. I think I am going to have to do the same kind of maintenance on MTL trucks as I am doing now on the Kato cars, and the repairs to MTL trucks and couplers will cost more than the Kato couplers.



pmcgurin;

Micro-Trains, and virtually all other brands of knuckle couplers, have to be adjusted to exactly the same height in order to stay coupled reliably. They also need to be inline with the centerline of the car, if body-mounted. Truck-mounted couplers are more-or-less self centering horizontally, but quite able to shift vertically, when traversing less-than-smooth-track.
A common example is the effect I call "frog bounce" found on practically all commercial turnouts. Wheels first drop down into the overly-deep frog, and are then dragged back up when they hit the frog point. This often causes the couplers to travel up & down, and sometimes uncouple. Truck-mounted couplers are extra susceptible since the arm they are mounted to bounces with the wheels of that truck as they go through the frog. By the way, it is far more reliable to pick, and use only one mounting system for all your couplers. Either all body-mounted, or all truck-mounted. A mixture of both will ;likely cause derailments or uncouplings.

Shimming the frog floor up to meet the bottom of an NMRA gauge's "flangeways" tab eliminates "frog bounce."
NOTE: While your shimming stuff, check the width of both flangeways. The guard rail flangeways are too wide on all commercial turnouts except Micro Engineering's. This causes derailments. Shimming them to touch the side of the "flangeways" tabs drops the odds of a turnout derailment. (See the attached files for details.)

Height discrepancies are the number one cause of unwanted uncouplings.
Micro -Trains sells a coupler height gauge which measures the height of the trip pin ("air hose") above the rails using a .005" plate, and the height of the coupler knuckle. The knuckle height is measured by eyeball against the coupler mounted on one end of the gauge. However, that gauge-mounted coupler itself can move vertically, and an eyeball guess is often less than accurate.

I came up with a more accurate way to measure coupler height, using an NMRA standards gauge with a pair of slots cut into it. (see photos)
The top slot accepts a coupler knuckle that is at the correct height. The bottom slot passes a trip pin that is properly adjusted. No eyeball guessing needed. The knuckle, and trip pin, either pass through their respective slots or, (if they're slightly off height) they don't.

Traction Fan 🙂


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## pmcgurin (Sep 7, 2010)

Thanks, Traction Fan for your detailed reply. What I see happening to some of my Kato passenger car truck-mounted couplers is that part of the "fist," if you will, is becoming worn away or broken off, so that the coupler reaches a point where it will not couple. These are original Kato couplers on Kato passenger cars that I have had in some cases since the 1990s. When the coupler's "fist" is worn away or broken it will not work and some kind of replacement is needed. I haven't actually had Kato couplers separate in operation.

Just now I checked a few MTL equiped Atlas cars, and the two that would not couple had part of the Fist worn or broken away. So, the couplers in question just do not have enough of the fist left to join up with another coupler's fist. I treat all this stuff gently, so I am left thinking that there is wear and tear, and some replacement must be in the cards. As long as the cost doesn't get ridiculous, I can do it. I suppose that it seems to be cheaper to use Kato with passenger cars that come with Kato couplers while going with MTL on freight cars that I don't do much with any more anyway. It does seem that I am seeing the same kind of wear on both kinds, and, when the coupler's fist is incomplete it has to be replaced to work. I don't know if this kind of wear is normal.


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## vette-kid (May 2, 2020)

pmcgurin said:


> You never have MTL couplers that won't couple with other MTL couplers? I have about 30% of the freight car couplers I have converted to MTL trucks that won't couple with other cars with MTL trucks and couplers. I replaced two of these trucks with two new ones I had on hand, and that fixed those. I don't know what the cause of this is, but I am hoping that portions of the couplers don't wear away or break away. It has been about fifteen years since I converted the freight cars to MTL, but the cars were stored for the last twelve years. The cars were gently treated, because all these small parts look delicate. I have a number of MTL cars and they sometimes won't couple with each other. I think I am going to have to do the same kind of maintenance on MTL trucks as I am doing now on the Kato cars, and the repairs to MTL trucks and couplers will cost more than the Kato couplers.


I do not have that issue. But I will admit that most of mine are pretty new. I know that any attempt at coupling a kato with an MTL results in frustration and any attempt at a truck mounted coupler mating to a body mount (other than the loco) is equally frustrating. 

I'm not sure how there could be much wear on these parts unless you have a LOT of run time with HEAVY trains. There just wouldn't seem to be enough force to cause wear against two relatively smooth surfaces. But you're experience would seem to indicate otherwise, so maybe it's something I'll have to deal with eventually. 

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## pmcgurin (Sep 7, 2010)

I have had my trains stored for long enough that most of them have been used for 3 to 5 years. Run times have been fairly short since putting MTL couplers on the freight cars. I set them up and run them for five minutes or so, and then put them away. Maybe I am doing something wrong with the rolling stock, but I thought I was handling them gently. It is interesting that the Kato couplers and the MTL couplers break the same way, with both ends of the "fist" wearing away. Well, these are tiny parts, and maybe it's just wear from coupling and uncoupling. Maybe it's the uncoupling that occasionally breaks a piece of a coupler off. I'll have to be more careful. Thanks for your ideas and experience.


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## traction fan (Oct 5, 2014)

pmcgurin said:


> Thanks, Traction Fan for your detailed reply. What I see happening to some of my Kato passenger car truck-mounted couplers is that part of the "fist," if you will, is becoming worn away or broken off, so that the coupler reaches a point where it will not couple. These are original Kato couplers on Kato passenger cars that I have had in some cases since the 1990s. When the coupler's "fist" is worn away or broken it will not work and some kind of replacement is needed. I haven't actually had Kato couplers separate in operation.
> 
> Just now I checked a few MTL equiped Atlas cars, and the two that would not couple had part of the Fist worn or broken away. So, the couplers in question just do not have enough of the fist left to join up with another coupler's fist. I treat all this stuff gently, so I am left thinking that there is wear and tear, and some replacement must be in the cards. As long as the cost doesn't get ridiculous, I can do it. I suppose that it seems to be cheaper to use Kato with passenger cars that come with Kato couplers while going with MTL on freight cars that I don't do much with any more anyway. It does seem that I am seeing the same kind of wear on both kinds, and, when the coupler's fist is incomplete it has to be replaced to work. I don't know if this kind of wear is normal.



pmcgurin;

As far as I know, model couplers wearing out is not normal. In fact, this is the first time I've heard of either MTL, or Kato, couplers wearing out. There have, however, been many references to cheaper imitations, (like EZ-Mate, and accumate) couplers not lasting very long.
The equivalent to MTL couplers in HO-scale, & O-scale, are Kadee brand, and they are made of metal, not plastic. Why Micro-Trains does not make metal couplers for N-scale is, I suppose, "their dirty little secret." Perhaps related to their lack of all-metal trucks, like those that Kadee has offered in HO-scale, for decades.

Coupler wear is also found on prototype couplers. The part you call a "fist" is more commonly called a "knuckle" in model railroading, hence "knuckle couplers." However, "fist" is perhaps a better description of the coupler's shape than "knuckle." I've described two mated knuckle couplers as "looking like a handshake." Perhaps looking like a "wrestler's grip" between two fists would be a more accurate description.

To clarify our terms, (and to tell me the exact location of the wear) I ask you to form an almost-closed fist with your hand. Leave it open enough that the tips of your fingers point straight back parallel to your forearm. Your hand should now have the hook shape of a coupler.
I'm going to call the set of knuckles closest to your fingernails K1, the middle set K2 and the biggest set, closest to your palm, K3. On prototype (and some O-scale) couplers the middle, K2, set of knuckles, is a hinged point. The coupler "lets go of" the coupler on the next car by letting the portion represented by the area beyond K2 (including K3) pivot outward.

Prototype couplers, when overstressed, can break this pivoting part off. This is called "a broken knuckle." Another possible failure is to pull much of the entire coupler right off the car. For either of these failures to occur, there needs to be a huge amount of pulling force from the locomotive, countered by a huge amount of drag from the heavy train it is attempting to pull.

To minimize the stress on the couplers, a prototype engineer will gradually "pull the slack out of the train." Couplers (prototype & many model) have built-in springs that let the coupler pull just a little bit out of the box that they're mounted in. (called "draft gear on the model)
As a train starts out, the locomotive pulls only the first few cars. As the slack inside, & between, couplers is gradually taken up, more & more cars start to roll. If the engineer applies too much power, too quickly, its possible to break a coupler knuckle. Some trains carry spare couplers to repair this sort of damage, much as we carry a spare tire in the trunk of our cars.
Its a little hard to imagine this same scenario happening to a model train. Our cars are so light. But I suppose anything is possible. 
Let me know the spot(s) that are wearing out.

Traction Fan 🙂


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## pmcgurin (Sep 7, 2010)

I have been looking for couplers still needing replacement.
The coupler on the left is a working Kato coupler. The center and right couplers do not join together nor will they join with other Kato couplers. If the center and right couplers look as if they should work, they do not, I tried them extensively.


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## traction fan (Oct 5, 2014)

pmcgurin said:


> I have been looking for couplers still needing replacement.
> The coupler on the left is a working Kato coupler. The center and right couplers do not join together nor will they join with other Kato couplers. If the center and right couplers look as if they should work, they do not, I tried them extensively.
> View attachment 578166


Your photo is not focused on the couplers very well, but it looks as if the center &right couplers are not as tight as the left one. While I can't see any obvious damage in this photo, its possible that there has been some wear. I don't know why though. A better-focused photo, with the couplers larger might help, but I may not be able to help you.

Traction Fan 😕


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## Old_Hobo (Feb 20, 2014)

Re-take the photo from the bottom of those cars, with a little better light…..hard to help if we can’t see the problem very well….


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## Viperjim1 (Mar 19, 2015)

Pm sent


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## pmcgurin (Sep 7, 2010)

I have found that most of these Kato couplers on passenger cars will wear at the ends towards the middle. The gray or black couplers from 20-packs that you have to assemble are easy to assemble and install. I replaced six couplers yesterday for example. These are delicate. I think if they were made of metal, they would last a lifetime, but cost is probably the reason why they are resin. I think it takes me about twenty minutes to lay the sprue with one side of the coupler on top of the sprue with the other side of the coupler, press them together, twist one off, press it sideways into the coupler box and push it over in place. Unless you do it backwards.


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## Old_Hobo (Feb 20, 2014)

I’m pretty sure they are plastic, not resin….resin snaps by just looking at it.…

All my Micro Trains couplers have lasted the life of the cars, so don’t know what’s happening with yours….


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## Matison (12 mo ago)

traction fan said:


> pmcgurin;
> 
> As far as I know, model couplers wearing out is not normal. In fact, this is the first time I've heard of either MTL, or Kato, couplers wearing out. There have, however, been many references to cheaper imitations, (like EZ-Mate, and accumate) couplers not lasting very long.
> The equivalent to MTL couplers in HO-scale, & O-scale, are Kadee brand, and they are made of metal, not plastic. Why Micro-Trains does not make metal couplers for N-scale is, I suppose, "their dirty little secret." Perhaps related to their lack of all-metal trucks, like those that Kadee has offered in HO-scale, for decades.
> ...


I was considering installing the newer couplers on my locomotive, but I keep hearing many negatives about them. The older style Rapido couplers may not look as good, but they are plentiful, inexpensive and hold up for years and years.
Is it really worth the time and expense to upgrade to Kadee? (I have not tried any yet) I understand that they look better, but do they work better?


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## pmcgurin (Sep 7, 2010)

A majority of new logos and cars come out with some kind of knuckle coupler, like Kato or Kadee. If you choose Rapido, you will have to retrofit with Rapido.

If you choose Kadee, you might have less refitting, and a chorus of most modelers will agree with your choice. It is probably best, and most realistic. 

If the Rapidos do not bother you, go with them, but you will have to replace a lot of knuckle couplers with Rapidos.

I used Kato couplers on passenger items. They are cheaper than Kadee, but I have replaced many, because they seem to be less durable. Kate's are easier for me to use with my eyesight, and eyesight can be an issue. I tried MTL couplers and could not install them.


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## vette-kid (May 2, 2020)

Matison said:


> I was considering installing the newer couplers on my locomotive, but I keep hearing many negatives about them. The older style Rapido couplers may not look as good, but they are plentiful, inexpensive and hold up for years and years.
> Is it really worth the time and expense to upgrade to Kadee? (I have not tried any yet) I understand that they look better, but do they work better?


I have nothing negative to say about MTLs. They work remarkably well. I'm running up to 30 cars (half are 89 footers) up 2.5% grade without issues. 

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## vette-kid (May 2, 2020)

pmcgurin said:


> A majority of new logos and cars come out with some kind of knuckle coupler, like Kato or Kadee. If you choose Rapido, you will have to retrofit with Rapido.
> 
> If you choose Kadee, you might have less refitting, and a chorus of most modelers will agree with your choice. It is probably best, and most realistic.
> 
> ...


Kadee does not make N scale. In fact, I believe MTL is the off-shoot of Kadee but specializes in only N scale. This split happened many years ago and you will not find kadee N scale any longer. 

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## pmcgurin (Sep 7, 2010)

You could always leave the Rapido couplers on the cars that have them and make an "interface" car with a Rapido coupler on one end and a knuckle coupler of your choice on the other end. I have a few cars like this, and they are handy.


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## traction fan (Oct 5, 2014)

vette-kid said:


> Kadee does not make N scale. In fact, I believe MTL is the off-shoot of Kadee but specializes in only N scale. This split happened many years ago and you will not find kadee N scale any longer.
> 
> Sent from my SM-G781U using Tapatalk


vette_kid;

You are correct. Years ago there was one company called Kadee. They made couplers, and other products, in several scales, including both HO and N scales. Kadee even made N-scale cars then. I still have some with the Kadee name on the price tag. (Would you believe $3 for a new car?) 
The Kadee firm was owned by two brothers. At some point in time they decided to go their separate ways, and split the company. One brother kept the Kadee name and continued to make products in HO-scale & larger. The other brother took the N-scale & Z-scale business, and named his new company Micro-Trains.

Traction Fan 🙂


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## Old_Hobo (Feb 20, 2014)

A concise history of Micro Trains can be found here:

Micro Trains History


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## GTW son (12 mo ago)

pmcgurin said:


> You could always leave the Rapido couplers on the cars that have them and make an "interface" car with a Rapido coupler on one end and a knuckle coupler of your choice on the other end. I have a few cars like this, and they are handy.


This is the route I have taken as most of my loco's have Rapido couplers.
One car has a Rapido coupler on one end and a Micro train coupler on the other.
I have one Kato loco with they're couplers and agree hooking Kato and Micro train couplers can be frustrating.


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## pmcgurin (Sep 7, 2010)

Yes, and I have a Kato Great Northern passenger set with kato couplers that will not all hook up to each other. Good couplers, probably, just don't all work together. I am going to look for MTL trucks for these. Or maybe sell them. Shame as I have put light kits in them.


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## GTW son (12 mo ago)

Years ago I took an old Life Like engine to the hobby shop and had Micro train couplers installed.
They worked great, sadly the loco croaked and those couplers can't be used on my Kato.
I was at the hobby shop the other day and apparently they are much easier to swap now but because of the plague the shop is not accepting customer repairs yet. Can't say I blame them.


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