Adjustment Of Couplers
Is Important For Reliable Operation
Of Model Trains

Adjusting couplers for best performance applies in any scale. My experience is mainly with HO, HON3 and G scale. I have some experience with N scale having built a small 4' X 8' layout as an experiment and operating on a friend's extensive N scale model railroad.

I have tried lots of different couplers over the years from dummy to Mantua, horn-hook, NMRA and the new plastic types that are essentially a variation on the tried and true Kadee coupler. I always seem to end up going back to Kadee because I find their metal couplers more reliable. 

Some of the newer plastic types can become distorted if the cars are left coupled on a curve for too long or they can pull apart under heavy loads on grades.

Kadee also make lots of variations to solve problems like close-coupling of engines and passenger cars, high and low mounting platforms and tank car platforms. It is often possible to lower a coupler box by gluing in a shim of styrene or a cutdown coupler box. Often the simplest solution is to use a Kadee #22 medium overset shank or a #27 medium underset shank. They also have short and long shanks.

A recent addition to the line is the HO #148 Magne-Matic "Standard" medium center-set head metal "Whisker" coupler. It is a drop-in design that replaces the metal plate that is used with the most common #5 coupler. They have self-centering action and come with snap-together insulated draft gear boxes.

Kadee also makes a #91 20-coupler sample pack that you can use to try different couplers to solve problems. Pilots on steam locomotives or snowplows can be the trickiest installations. That's where the sample pack is really a big help.  

I have even changed my G scale cars to body-mounted Kadee couplers. This can be a lot more difficult than converting HO cars because most cars from US Trains, LGB and Aristo-Craft have talgo-type trucks. 

Kadee has gone to great lengths to provide instructions for all kinds of mounting situations and include lots of shims and conversion pieces to help you.

There are a few instances where I have resorted to a talgo-type coupler/truck combination. Tank cars can be a particular problem for body mounting because the platforms don't offer much in the way of support. Drilling for screws leaves a noticeable protrusion.

Talgo style trucks (or bogies) is where the coupler is mounted to the trucks instead of to the body of the car. They work well when they are being pulled but have a tendency to derail when pushed backwards. This is due to the coupler shank being forced off center, especially on curves. This appears to be a bigger problem in the smaller scales, but I haven't tried to do a lot of switching with the G scale cars. My engines are usually just pulling them.

Coupler and weight adjustment board
weight and coupler adjustment

I always use an NMRA gauge and a Kadee height adjustment coupler as seen here on the right end of my weight and coupler board. Kadee makes fiber washers in 1/32" and 1/16" sizes that can be used to raise the wheels if the trucks are too low.

Kadee pliers are the ones
on the left
Kadee pliers

There is also a special pair of Kadee pliers that allow you to bend the trip pin so it doesn't drag and snag the rail tops when crossing turnouts. Kadee's system of delayed magnetic coupling can be used to uncouple cars so you can push them back into sidings. 

There are also electromagnets for the mainline that you energize as the couplers pass over them. This is because the permanent type magnets placed between or under the rails can uncouple the cars if they stop momentarily while passing by. This can happen if there's some dirty track in the vicinity or a locomotive isn't picking up power at all times.

Uncoupling tools
uncoupling tools

Uncoupling tools

Here are some typical uncoupling tools that can be used in HO, N and smaller scales.

The LED light (top) is to read car numbers. The uncoupling tool with the magnets is by Rix. A variation on the kitchen skewers is the dowel with a metal wire hook to catch the glad hand hose on the coupler.

Although I have some magnets installed, we usually use wooden kitchen skewers to manually uncouple cars. They're cheap and they work well. You can also use dental picks if you have any. Ask your dentist if he or she has any old ones they'll be throwing out.

If you want to use magnets, there was an interesting article by Charles Davis in the November, 2008 issue of Railroad Model Craftsman. The article was about installing small, cylindrical magnets between the rails. The magnets he used instead of Kadee bars are round neodymium magnets. They are as unobtrusive as a typical light emitting diode you might use for signalling. You can buy them in various sizes. They'll work for delayed uncoupling. The trick is to get them to the right height and learn how to stop cars over them.

Charles wrote he has a friend who has used these magnets on his S scale layout with good success. He noted that with the trip pins adjusted to the recommended 1/16" above the railhead, the magnets worked well with Kadee No. 802 couplers. The magnets were installed 1/16" below the railhead to minimize false trips by steel axles being pulled to the magnets. This would probably work in O scale, too. Again, it's a matter of trial and error. That's why it's good to try it on the club layout before doing it at home!

We are considering trying this method on our Nottawasaga Model Railroad club layout. One of the sources we found was Lee Valley, the tool company. You can also source them on the Internet. Try

Kadee RC remote couplers

In the February, 2013 NMRA magazine, Kadee advertised remote couplers that open and close with a push of a button. They are designed for G scale and #1 scale. Go to for more information.

Remote couplers operated by DCC are also now available in HO scale.  They are pretty neat to watch but way beyond my budget or time constraints. 

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