Bachmann Spectrum Cars keep uncoupling

[New ChooChoo]

   I have a set of the Bachmann Spectrum heavyweight passenger cars. I replaced the horn hook couplers with Kadee #148 Magne-Matic couplers. It doesn't matter if the cars are going on a straight away or around a curve, one or two of them keep uncoupling. I noticed that the cars have the coupler boxes that pivot with the trucks. I am running 18" curves due to limited space. I have tried replacing the couplers with fresh ones, but it still keeps happening. Any ideas on how to prevent this. Do they make a coupler that is solid as I don't have the need for uncoupling the cars.

[OldTimer]

Kadee invented the magnetically operated knuckle coupler, so they don't get much more "solid" than that.

Uncoupling problems are usually caused by the couplers being at different heights.  If you don't already have one, get a Kadee coupler gauge...It will show you if your couplers are at the right height and also show you if the trip pin is too low and prone to snagging on tournouts.

My experience with these cars is that the coupler boxes sag.  I replaced the pivoting boxes with ones screwed to the underframe, but that might not work because of your sharp radius curves.  You might try making a cradle out of a paper clip to support the coupler box.  Bend a paper clip into a shallow U shape, enough wider than the coupler box that the wire lets the box pivot and enough deeper than the coupler box to be able to attach to the car and still support the box.  Drill a hole on either side of the box the size of the paper clip wire.  You want a press fit.  Insert the legs of the U into the holes.  Use your coupler gauge to adjust the height and, when the coupler is where you want it, secure the wire loop to the car floor with a drop of ACC at each end.  Hope this helps.  Merry Christmas.
OldTimer

[New ChooChoo]

Hi there Oldtimer,

   I did some more investigating and found that indeed the one car's coupler was sagging like you said. I also noted that one of the couplers on another car is a different height when coupling to the car in front of it. Strange as both cars are identical.
   I have heard and seen couplers that fasten to the bottom of the car body. I am going to experiment with one or two cars and see what I can come up with. Also the trucks turning in sync with the coupler bothers me too. Thanks for the info and I'll be sure to let you know how things turn out.

[jward]

85' passenger cars with body mounted couplers aren't going to like 18" radius curves. this is one of the few cases where i'd recommend leaving the horn hooks on and using an adapter car with a kadee on one end and a horn hook on the other.

trying to use truck mounted knuckle couplers has been, in my experience, an exercise in futility. for exactly the reasons you have given. unpredictable coupler height due to the inherent instability of a truck mounted coupler mount, especially one with a long "tongue" like your passenger cars. horn hook couplers are not that sensitive to mismatches in coupler height, kadees are....another problem, which shouldn't affect your passenger cars as much as other types, is the tendency for truck mounted couplers to derail the cars while backing. you probably won't back passenger cars much so you could get away with keeping the truck mounts in order for them to run around your 18" curves.....

[Jim Banner]

If the couplers still uncouple even after you have adjusted them all to the same height, there is another thing to check.  Kadee and Kadee style couplers rely on both their centering springs and jaw springs to stay coupled, particularly if the cars are bouncing back and forth a bit.  Kadee is very specific about how to install their couplers and yet many are installed with the centering spring upside down and rough edges left unbrinelled.  And when it comes to smooth centering action, many modellers do not even own a tube of Greasem or other brand of graphite.  Kadees are quite reliable when installed properly but installing the centering spring incorrectly, skipping the brinelling or failure to lubricate them can cause a host of problems.

Jim

[New ChooChoo]

 The couplers on my heavyweights pivot on the bottom of the car. The trucks and the couplers are are connected together via a link and they turn together. I am going to play around with things and see what I can come up with. Will keep everyone informed and thanks for all your responses.

P.S. Does someone make a non operating coupler? One that doesn't open.

[Jim Banner]

Does someone make a non operating coupler? One that doesn't open.

It is easy to convert Kadee type operating couplers to non-operating ones.  One small drop of ACC (Crazy Glue) in the jaw hinge is all it takes.

Jim

[ACY]

I have IHC cars that had the same problem as your Spectrum passenger cars. I fixed it by body mounting long shank Kadee couplers, you just need a coupler height gauge to ensure they are mounted level I also mounted then on small pieces of styrene to ensure the boxes were level. The catch is that you need at least 26" radius curves to run them, but they do so with out any issues. I also replaced the wheels with metal wheel-sets and added a bit of lead to add some weight to improve tracking.

[Len]

Another option is to use either McHenry or Kadee 'shelf' style safety couplers. The shelf is similar to that found on horn-hook couplers, but smaller. It will keep the couplers from bypassing each other if there's a slight height difference when coupled.

Len

[Doneldon]

New Choo-

I endorse Jim's suggestions about Kadee couplers. My trains ran so much better, and my couplers became so much more reliable, after I removed all of them, burnished the coupler heads and shanks, and shot a little grease 'em on them.

To answer another question, yes, there are non-operating couplers. They're called dummy couplers. They have the advantages of not uncoupling without human intervention and of giving a more prototypical appearance. They can be a good solution for passenger trains which don't need to be broken down and reassembled. On the other hand, you do give up some operational ease with non-operating couplers, and you must still use long shanks to get long cars around tight curves.
                                                                                                                                                                                                               -- D

[New ChooChoo]

    Well here is the latest on the problem of the passenger cars that uncouple.  I took one car and took it all apart. Got rid of the stock Bachmann coupler and the linkage inside the car connecting the coupler and the trucks. There also was a little tab inside the car that prevents the truck from pivoting too far to one side. Took a drumel tool and whisked that off smooth with the floor of the car. I installed Kadee #148 couplers and gear boxes to the bottom of the coach. If its a 4 wheel truck, it will clear the gear box. If its a 6 wheel truck, I needed to burnish the back end of the gear box off so the truck would clear it. When the cars are coupled together, there is still just the right amount of space between them. The diaphragms are about 3/8" from each other and look good. I have 18" curves and the cars go around them with no problems. The biggest fear was I would destroy the car,but ya never know unless you try!

[Doneldon]

New Choo-

Congrats! Your first problem solved. Good for you.
Unfortunately, problem number two is just around
the corner. But now that you know you can fix these
things, it will be less daunting.
                                                         -- D

[mr. mick]

I am curious as to how you disassembled the Heavyweight car so as to reach the truck to coupler linkage. Also, were you  working on a new heavyweight car or an older one?  I have an older heavyweight that I need to reattach the coupler, and the linkage, but I could not figure out haw to get the car disassembled to reach the inside linkage.


Any suggestions would be appreciated,

Mr. Mick