Aristo Evans Car & Kadee Retrofit

Aristo EVANS Car and Body Mount Kadees
Ted Doskaris
May 15, 2011
Rev GE-A


The Aristo-Craft EVANS car can be fitted with the Kadee 830 or newer 906 AAR type "E" body mount coupler assemblies.
The example car shown below is with the Kadee 830 installed.

There are two, albeit similar, methods I considered for installing body mount Kadee coupler box assemblies on the Aristo EVANS car.

Kadee Coupler Box Mounting, Method 1:
The first method is exemplified using the British Columbia Railway (BC Rail) car. 

For either method, the Kadee coupler box assembly needs a spacer for obtaining the car's proper coupler height to the rail head.

This first method involved the use of plastic material salvaged from left over floor assemblies from Aristo 40 cars I had retrofitted with "lowered floors".

By trimming and cutting out much of the pad area near the salvaged floor's bolster, this provided the material needed for the spacer.

Cutting a slot near one end of the spacer allowed it to be installed over the lip of the end bulkhead of the EVANS car where a screw was placed to hold the front of the coupler box to it - but not to the car.

I was able to mount the whole assembly (spacer & coupler box) to the car with only one screw at the rear of the assembly.

The one screw mounting operationally worked but not to best expectation on long, heavy trains; so I later put two additional, relocated side mount screws to secure it - discussed subsequently.


The coupler box assembly is purposely mounted to project outward by 0.75 to 0.80 inches to emulate that of the prototype car.

These pictures show the BC Rail car in a train being pulled by two USAT SD70s operating on 10 foot diameter curve track on my layout's 270 degree loop back.

The first method proved to be too time consuming for cutting the salvaged material since I had to mount coupler assemblies on 31 EVANS cars.  For the 30 remaining cars, I chose to purchase inexpensive spacer material from TAP Plastics, and this proved to be more practical.

Kadee Coupler Box Mounting,  Preferred Method 2:

Shown below are examples of Aristo-Craft 53 foot EVANS box cars having been fitted with body mounted Kadee centerset couplers similar to that of the first method.
The Boise Cascade car is of an earlier Aristo factory production run.
The Southern Pacific Hydra-Cushion and BNSF cars are of a recent Aristo factory production run

There is no difference between the two generations of cars with respect to the Kadee coupler installation.

The Aristo EVANS car can be fitted with the Kadee 830 or newer 906 body mount coupler assemblies. The examples shown here have the Kadee 906 coupler assemblies.



Since these cars are models of the prototype cars having cushion type under frames (Hydra-Cushion, Shock Control, etc.), the coupler boxes are desirably mounted so that they project beyond the end of the car like the prototype of which an example is shown below.
Shown below is an Aristo EVANS car example with modified and installed Kadee 906 coupler assembly that closely emulates the prototype car's coupler box striker plate projection.
It can be seen the coupler box striker plate measures about 0.75 inch from the end bulkhead of the car.

Shown Below is an Aristo C&NW car on the left mounted with the newer Kadee 906 assemblies and the BC Rail car on the right with the older Kadee 830 assemblies.
The cars are shown on an 8 foot diameter curve track.
For the cars to operate on 8 foot curve track, the coupler boxes' sides need to be notched to some extent - to be discussed later.

The coupler boxes themselves are the same whether using Kadee 830s or 906s; however, the boxes do require easy to do modifications for relocating the two side mounting screw holes to best attach the box and that allow for car operation on tighter 8 foot diameter curve track so the wheel flanges don't interfere.
It can be seen that the coupler will swing OK within the box when additional clearance holes are added for the 2-56 mounting screws so the box can be mounted in a projected position like that of the prototype car.
The material removed from the sides of the coupler box between the new side mounting holes and Kadee holes allows for car operation on 8 foot diameter curve track.

Kadee Coupler Box and Spacer Drawings:

Shown below are drawings of the Kadee coupler box modifications and a custom cut spacer that is needed for mounting of the box so that the coupler will have the proper height from the rail head.
The spacer material is very inexpensive. I purchased two 3/16 inch thick by 1 1/16 inch wide 4 foot long ABS strips from TAP plastics. This was enough material to do about 30 EVANS cars.

The first car I modified (method 1) was the green British Columbia (BC) Railway car.  I did this car before purchasing the TAP Plastics material.  At that time I used a plastic spacer cut from salvaged Aristo 40 foot box car floors left over from installing Aristo's lowered floor kits in those type cars. That took some time to do, so getting the low cost TAP Plastics material was the way to go to modify any quantity of cars, that in my case, was 31 EVANS cars.
The gouges seen on the side of the coupler box were caused by car operation on 8 foot diameter curve track, whereby, the wheel flanges made physical contact. That's why this area needs to be trimmed.

When doing the BC Rail car, I only used one screw to hold the coupler box and spacer to the car's floor pad, and I used another screw to hold the projected end of the coupler box to the spacer.  Surprisingly, this worked pretty good during train operation, but with one screw holding the entire coupler box / spacer assembly to the car, there was a tendency for the coupler box to move slightly from side to side during train operation - even with the spacer's slot resting up against the end bulkhead. Thus, I decided to go with the added, albeit, relocated side mounting screw fasteners to best secure the coupler box assembly to the car.
For subsequent cars using the coupler boxes having the two relocated side mount holes for fasteners, the screw with nut shown in BC Rail car's coupler box forward center hole proved unnecessary and was not used.

Cutting the spacer Slot:

A slot cut made 0.110 inch wide by 0.050 inch deep located 1.40 inch from the end of the spacer is necessary so that the spacer will project past the end bulkhead of the car. This is because the bulkhead lip extends beyond the car's floor, and it is desired that the added spacer projection provide support of the coupler box assembly with its lid in place.

I used a table saw fitted with a fine tooth blade suitable for plastic to cut the slot in the spacer.

The reason why the spacer width is desirably made 1 1/16 inch wide is that when it is placed on the car's floor pad area, it can be positioned against a floor rib that just happens to stick up a bit more than the mounting pad surface. Thus, the spacer is very close to being centered when it is placed against the side of that rib.

Coupler Box / Spacer Installation:

For determining where to locate the holes to be drilled in the floor pad area, the spacer can be used as a template by placing it on the pad and using a small scratch-all tool to scribe the hole locations.
Once the holes are scribed, the scratch-all tool can be used to "prick" the center of each hole for anticipated drilling.
A pin vise can be used to drill out the holes. I typically use a small pilot drill first and then follow with the drill size for tapping the 2-56 screw thread for the Kadee supplied screws.
Once the holes are drilled, a 2-56 tap is used. By tapping the holes, there is no need to use nuts to hold the coupler box and spacer in place, thus, not having to remove the entire floor assembly to put nuts in place. (Remember, the EVANS car does not have doors that open so you can't easily get inside to install nuts.)
Example Aristo EVANS cars are shown with Kadee supplied 2-56 mounting screws.

After the holes are tapped, the spacer can be placed down on the pad.
After the spacer is placed over the floor pad, the modified coupler box assembly can be installed and screwed down using the Kadee supplied 2-56 screws. 
Kadee typically supplies only two 2-56 screws in their 830 or 906 kits, so you may need to acquire the third screw from another source.

Fine Tuning Coupler Height:

On a minority of cars (or on one end of a car) an additional shim may be needed in order to get best coupler alignment with the Kadee 980 or 880 coupler to rail head gauge. I used a piece of roofing paper in these examples.



Sometimes the coupler box may need a bit of leveling. I found that using a Kadee shim that measures about 0.010 inch thick will work when slipped under the end of the box as shown below.

Fine tuning for car operation on curve track:
(This is particularly important on 8 foot diameter track that is the targeted minimum diameter for car operation with Kadee body mount couplers.)

With Kadees boxes mounted and pushing the car back and forth on an 8 to 10 foot diameter curve track, there will be tell-tail marks left on the sides of the boxes where the wheel flanges interfere. Also, there will be noticeable drag when doing this on 8 foot diameter curves.
As shown below, note the tell-tail marks on the sides of the coupler box.

The coupler box sides need to be notched near the original mounting holes for car operation on 8 foot diameter curve track. Sometimes there is tell-tail evidence of wheel flange interference on the coupler box even when operating a car on 10 foot diameter track curves - though I did not notice any appreciable drag in this circumstance. That said, trimming the box is desirable for when operating the car on 10 foot diameter curves, too.
I used a Dremel tool having a conical stone to grind the sides as shown below.

Providing a notch on the coupler box sides allows the car's wheel flanges a bit more room so they don't bind against the box whilst the car is traversing an 8 to 10 foot diameter curve track.



Operation on the layout:

The Aristo Union Pacific RS-3 trailing unit (retrofitted with Datum Precision custom made metal coupler boxes and Kadees) seemed to be the worst case of my six RS-3s for flexing its pilot when stressed pulling the 61 car train, particularly when rounding the 270 degree loop back on my under house layout as shown below.

Shown below is an outside view of the couplers on the 10 foot diameter loop back.

Shown below is the top view.

The coupler alignment was better with less stress on the 8 foot long straight section of the layout as shown below.

Any coupler stress is more with respect to the RS-3 loco's pilot distorting under load pulling the long, heavy 61 car train rather than due to the EVANS car. Anyway, the EVANS car with its Kadee retrofitted coupler assemblies perform without incident and was extremely well behaved when being operated on the layout.



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