Body Mounting Kadee 830’s onto an Evans 53’ Boxcar
Moving beyond factory truck mounted couplers.
Keith Stratton



This article describes, step by step, how to replace Aristo’s truck mounted couplers with Kadee body mounted 830’s.


First some background. My start in model railroading, like many others, was in HO before I gravitated to my current, and favorite, scale of G. One of the first things I noticed when I began exploring rolling stock was the predominance of truck mounted couplers. I remember thinking to myself “that just doesn’t look right”! In HO all of my engines and rolling stock had body mounted Kadee couplers and I saw no reason to deviate from that product in ‘G’. I was pleasantly surprised to learn that Kadee had quite a range of G scale couplers so the decision to go that route was made very quickly.
All of the G rolling stock that I own as well as most of my locomotives has, over the past three years, been converted so I’ve done quite a variety of installations. A number of people have suggested I should write an article about these conversions and what you are about to read is the first in a series of Kadee conversion articles, as each type and make of rolling stock can require very different solutions.
My personal coupler favorites are the Kadee 830 and 930 (black or brown). They are very robust, can be modified easily and they couple together oh so effortlessly. One feature that I really like about the Kadee 830 / 930 are that they are straight shank couplers, and without any offset, which don’t downward like a 787 or 789 when pulling a heavy load.
To determine the relative strength of a number of manufacturer’s couplers, I performed straight line pull tests to the point of uncouple or failure, and this is what I discovered:
• Aristo-Craft stock plastic AAR couplers became uncoupled at 15.5 lbs.
• USA Trains stock plastic AAR couplers became uncoupled at 18 lbs.
• KD 830 / 930 couplers failed at 51 lbs. when the pawl snapped off.
I knew I wanted to pull long trains so these tests pretty much sealed the deal for me. Everybody has their preferences, these just happen to be mine. I’ve often heard there is no right or wrong way to approach G scale model railroading, as long as you enjoy the ride!
Now to the task at hand, converting an Aristo-Craft 53’ Evans Boxcar (with metal wheels)!

Picture 1

Picture 2

You will see in Picture #1 the tools used for the conversion. A piece of track and one (or two) Kadee coupler height gauges, a #54 drill, a scribing tool, a chisel, a hobby knife with a #11 blade and a Phillips screwdriver. Picture #2 shows the supplies needed. This list is for one coupler assembly and will need to be doubled for both ends of the Boxcar. One Kadee 830 or 930 coupler, three Kadee 841 coupler draft gear box shims of 1/16” thickness (but have some 1/32” shims available for final adjustments), one #4 x 1” pan head Phillips screw (for the center / middle hole in the coupler gear box) and one #4 x ¾” pan head Phillips screw (for the hole at the center / rear of the coupler draft gear box).
If you move the coupler gauge up to the end of the boxcar you’ll notice that the underside of the floor is above the flat of the coupler gauge. The shims are needed to bring the coupler draft gear box down to the correct height above the rail heads.

Picture 3

Picture 4

In Picture #3 you can see that one of the shims has had the end trimmed off just ahead of the outside mounting holes. The end sill of the Boxcar sits slightly lower than the underside of the floor and this first 1/16” shim will make up for that gap. We also want to mount the coupler draft gear box as close to the end as possible as the prototype coupler draft gear boxes protrude out from the end of the car. Take the trimmed shim and line it up as shown. While holding the shim firmly in position, take a scribe and run it around the inside of both center holes. As seen in Picture #4, the hole outline is shown. Then use the scribe to mark the center of each hole.

Picture 5

Picture #5 shows the scribe in place where the left side hole is marked out. Push and twist the scribe point into the center mark to create an indent for the drill. The #54 drill bit is shown ready to drill the pilot hole on the right side hole marking.

Picture 6

Picture 7

The hole on the left side in Picture #6 has been drilled and the hole on the right hand side has a screw in place. One thing you will notice is that when you screw into plastic, a raised mound will extrude up around the base of the hole as shown in the right side hole in Picture #7. This raised edge must be cut, shaved or chiseled off otherwise the coupler draft gear box will not have a flush fit against the underside of the Boxcar floor mounting pad. The hole on the left side has had the raised mound removed.

Picture 8

Now it is time to assemble the coupler draft gear box, shims and screws so we can complete the installation. In Picture #8 I’ve installed the screws through the coupler draft gear box, and then slid on the shims (with the trimmed one going on last). You can also use tow 1/32” shims if you run out of the 1/16” shims. If you look closely that is exactly what I did! Now move the assembly into position and screw it into place. Make sure the screws are tight but not to the point of stripping out the holes (don’t ask me how I know about this…).

Picture 9

Picture 10

Picture #9 shows the installed coupler assembly showing how the installation of the shims lowers the coupler, from the underside of the car, to the correct height. Picture #10 indicates where the wheels make contact with the side of the coupler draft gear box on tight radius curves. On my layout I have very large radius curves and this is not an issue. Many of you have tighter radius curves and will likely have to modify the coupler draft gear box before installing it. A very quick way to increase the turning radius is to cut off the side mounting holes that extend outwards on either side of the coupler draft gear box. If you still need more turning radius then cut into the box even further. This is easy to do and will not affect the working of the coupler, as long as you don’t cut in too far!

Picture 11

Now it is time to put the trucks back on and check the coupler height against the Kadee height gauge, as shown in Picture #11. As you can see this one is just right, but I’ve had some installations where the coupler gear box has had to be raised or lowered slightly, and that is where the 1/32” shims can come in very handy indeed!
Well, now you are ready for the layout. I hope you have found this information helpful, even if you don’t run Kadee’s!!! Stay tuned for more articles on how to install these wonderful couplers on our 1/29 scale treasures…


Keith Stratton – CCO (Chief Custodial Officer)
KD Rail