Aristo-Craft 40' Double Door Box Car & Kadee Couplers

Aristo-Craft's 40 foot Double Door Box Car &  Kadee Couplers
Ted Doskaris
Revision GE-A
June 22, 2009


This vignette started out from a perspective of operating a train of 40 foot type Aristo cars having standard Aristo truck mount Knuckle couplers but with a transition car employing a body mount Kadee 830 type coupler assembly on one end for coupling to a Kadee equipped loco.

That said, the material presented here having to do with installing a Kadee 830 type assembly will also apply to installing such couplers on both ends of a car and is applicable to other Aristo 40 foot single door box cars, reefer cars and stock cars - all of which share the same floor assembly.

Though the Aristo 40 foot gondola and flat cars also share the same floor assembly, other considerations must be addressed for those types, and that will not be included in this vignette. In this regard, Greg Elmassian describes a method for installing the Kadee 830 coupler assembly on this (his) web site for the Covered Gondola

It is to be appreciated that Aristo's 40 foot type floor assemblies have evolved over time. Original versions caused cars to assume a toy like elevated height. This was subsequently corrected by a "lowered floor" version but at that time did not include a ribbed walled coupler pad area meant to facilitate mounting Kadee model 830 type coupler boxes.
Then a newer version followed that did include the ribbed walls. The example floor used in this vignette is a to date version that includes both the ribbed walled coupler pad as well as underfame clearance allowing for remounting the Aristo truck 180 degrees without having to cut off its coupler tang.

The relatively new 40 foot Aristo Double Door box car will be the example used for the Kadee installation.

The Aristo DD box cars:

I acquired four new Aristo double door (DD) box cars - two in Southern Pacific, one Milwaukee Road and one Southern RR. These cars have operational sliding doors that when closed are secured with a latch like that used on Aristo's single door box cars.
I believe these cars are of the 3rd Aristo factory production run of the DD cars when compared to a previous MKT road name car that was included in the 2nd production run.
As is commonplace for Aristo the cars came with factory installed plastic wheels, so I retrofitted them with metal wheels. The metal wheels influence the installation of Kadee couplers due to their difference in diameters.
I installed a Kadee 830 coupler assembly on one end of one example car described here so as to facilitate a Kadee equipped loco coupled to it. This car serves as a transition car for pulling a train of cars otherwise equipped with Aristo Knuckle couplers.

The following pictures show these new cars with retrofitted metal wheels:

Two road numbers are offered so I got two SP cars as this is my core railroad of interest

The Southern RR car is shown below

The Milwaukee Road car is shown below

Most welcomed, Aristo have addressed concerns from earlier production runs of these DD box car products - yet some factory assembly issues remain of interest:

Thankfully, it appears Aristo resumed their past conventional packaging of rolling stock - a good thing since the recent all plastic box was awkward to work with - particularly when trying to put back the goods in it. (I had cut myself a couple of times on the sharp edges of those clear plastic boxes.) Shown below is the conventional packaging these cars now come in.

As shown below, and much appreciated, Aristo appears to have re-corrected the floor installation orientation whereby the large air tank is nearest the NON brake wheel end of the car as it should be. (The last production run DD MKT car had reverted to the incorrect installation practice.)

However, the Aristo factory needs some direction for the proper installation of the floor assembly as all four of the cars I received had one or more gaps between the side walls of the car and the surrounding edges of the floor. See below picture.

This was corrected by backing out the long  screws near these areas (along with the end bulkhead screw) and holding in the car sides against the floor whilst putting upward force against the floor from within the car until the sides popped into a flush position. Then LIGHTLY tighten the screws for a snug fit. If the screws are too tight, the sides will pop back out - which may be how the factory had assembled these cars.

The floor assembly & Kadee couplers:

A good thing is that Aristo appears to accommodate the 180 degree reinstallation of their trucks (with couplers removed). When the truck is rotated from side to side its coupler tang is now free to move without interfering with the floor structure. This facilitates body mounting couplers as it is no longer required to cut off the tang.

The following is with respect to accommodating the Kadee #830 G-scale straight centerset shank couplers with standard gear boxes as shown at the Kadee web site:
Kadee 830 G scale coupler

Mounting Kadee 830 box using Aristo's (as provided) floor pad location:

Shown below is the coupler pad area for accommodating a body mount Kadee 830 box. Also, it is much appreciated that Aristo's factory has apparently fixed the bolster pivot post where the trucks mount. The first production run cars had split pivot posts.

Note the 3 holes that are located outside the periphery of the ribbed walled area are intended for mounting the box. The wall height serves as a spacer to approximate the location of the desired coupler to railhead distance once the Kadee 830 assembly is installed. The walls also provide clearance for the end bulkhead screw head. (An apparent alternative mounting method would be to use only the rear hole and center front hole of the Kadee box - if one could locate an extra long bulkhead screw (or threaded rod and nut) - requiring removing Aristo's present long screw and using the extra long replacement for it to pass through both the Kadee box and floor assembly attaching to the body shell near the roof.)

Shown below is the mounted Kadee 830 coupler box assembly fastened with 3 one inch screws for a 3 point mounting method.

Note the 3 point mount of the Kadee box:

I used screws salvaged from an old answering machine having a thread pitch meant for threading into plastic. They appear to be about the size of a #4 screw of approx. 1 inch in length. (The holes in the floor pad area are to be drilled through with a smaller size diameter than the screws so as to accept the screw threads.)

Shown below is how the screws threaded through the floor surface within the car.
(Noticing the warpage at the far end, it appears the factory did not fully seat the upper floor board area to its lower section.) The camera found this issue!

Long #4 machine screws could be used with nuts attached at the floor area, but since the car's end bulkhead long screw is captively located under the Kadee box, placing your hand within the car would be necessitated to fasten the nuts by feel. (The end bulkhead long screw being covered over by the Kadee box precludes removal of the floor.)

Retrofitting metal wheels, lubrication & axle skew:

Since these Aristo cars came with plastic wheels, I retrofitted their Bettendorf trucks with Aristo ART-29111B metal wheels.
In the more recent Aristo factory production runs of the DD cars, I noticed the use of a blue / green grease on the axle tips after removing the plastic wheels. The cars described here did not have evidence of any lubricant, so I used a Teflon powered lube in the bushing areas of the journal boxes. Any excess can be cleaned off with a cloth.

Some time ago Aristo-Craft's principal officer, Lewis Polk, recommended the use of Labelle 134 for this purpose as being safe following the cracked journal box problem brought forth when using Electralube on plastic materials that the truck side frames had been made of.
(Newer production run Aristo freight truck side frames are made of a nylon material that do not appear to be damaged if using Aristo's Electralube. But if one is not sure what the material is, it's best not to use Electralube and risk damage.)  

Before installing the metal wheels, I placed a 0.030 inch thick nylon washer on  either end of the axle tip before installation. This is done to minimize axle skew (e.g. angle of attack of wheel flanges against rail head) with resultant wheel drag when rounding curve track. The hole in the washer is about 0.120 inch diameter for it to fit over the axle.

Shown below is a comparison with the truck on the bottom equipped with the 4 washers - 2 on each axle. The comparative difference can be seen between the two with the bottom example having noticeably less skew than the truck shown at the top that only had the metal wheels installed in place of the original plastic ones.

Lateral axle displacement could still be minimized - perhaps by using up to 0.045 inch thick washers; however, too thick will cause rotational binding as I have found when using 0.060 inch thick washers.

I wrote about the effects of axle skew, and it can be found within topic, 'Aristo-Craft Metal Wheel "train accessory" kits and wheel issues' at Freight truck wheel / axle skew  and drag issues

More Kadee coupler info. following truck reinstallation:
(Now that the wheels have been chosen)

Shown below is the Aristo Southern Pacific DD Box car with a Kadee 830 coupler box assembly installed on one end of the car and how it aligns with the Kadee 880 Coupler Height Gauge.

The car coupler aligns reasonably close, but as can be seen it's a bit too low.
Since Aristo supplies a metal washer of about 0.012 inch thick mounted on top of each truck bolster at the pivot post, this could be placed on the underside of the truck (over the pivot post of the floor bolster) thus raising the car up some for better coupler alignment. However, I have found the car to exhibit excessive rocking or wobble when doing so. (Incidentally, this is how Aristo shipped the earlier production run DD cars, and it's appreciated they still include the washer.)

As to this height mismatch, it should be understood that the car as equipped from the Aristo factory is supplied with plastic wheels and these wheels measured to be about 0.020 inch greater in diameter at their tread when compared to the Aristo ART-29111B metal wheels that have been retrofitted here. Thus, one half of this (0.010 inch) is difference the amount that the car would be lowered with these metal wheels installed. It's possible Aristo may have overlooked this and designed the floor pad coupler wall height, accordingly. If so, consideration could have been afforded to folks who would want to mount Kadee couplers would also likely want metal wheels on their cars, too.

The picture below shows how the coupler alignment appears with 0.012 inch thick spacer washer placed between the car floor bolster and truck - thus raising the car up by that amount.

This looks to be close in alignment to the Kadee 880 coupler gauge with maybe just a tad still too low.
Since the car exhibits rocking with this spacer washer, my preference is to trim the coupler pad wall height down by about 0.015 inch - though later I discovered I had to remove 0.040 inch! (This will be discussed later.)

The following picture show what the car looks like with the Kadee 830 coupler assembly installed without any trimming:

Note how the coupler box seems to project out from the end of the car.

This coupler box projection favors a wider space between coupled cars - of benefit with paired cars when rounding tight curves.

When comparing the coupler box projection to prototype cars, it would appear that this would best emulate Southern Pacific's "Hydra Cushion" or Santa Fe's "Shock Control". For the more common era cars, it may be of consideration to mount the coupler box assembly more flush with the bulkhead end of the car, but this would require drilling new mounting holes in the car floor and also require trimming some material off the Aristo truck bolster tang. See below picture:

The below picture illustrates how the Kadee 830 box tends to restrict the rotation angle of the truck when compared to the Aristo truck mount coupler. (The wheels' backsides contact the Kadee box.) This may be of concern if operating the car on tight diameter track curves.

And look what happened when I ran the car on 10 foot diameter curves! You can see the telltale rub markings on the backsides of the wheels. As expected, there was noticeable drag on the car going around those curves.

One solution would be to cut off the outboard mounting holes on the Kadee box and use its two longitudinal center axis mounting holes - but then you would be forced to use an extra long screw (or threaded rod with nut) to pass through both the front hole of the Kadee box and the floor for attachment to the car body as previously described.

Mounting Kadee 830 box in a prototypical location on Aristo's floor pad:

At this point I decided to remount the Kadee box with its striker (box face) aligned with the car's sill (end bulkhead). Also, I wanted to see how the Kadee supplied # 2-56 machine screws with nuts would fit - so I used them.

A suggestion for Aristo to improve the freight car floor assembly:

Many folks may install Kadee 830 couplers on their freight cars, including the Aristo 40 foot box car products, and if doing so, it's reasonable they also would be predisposed to install metal wheels (likely ART-29111x). Therefore, by improving the floor assembly to accept various installation possibilities is behooving to do.
Thus, the Kadee couplers installation may be considered a catalyst of sorts - serving to enhance the sales of both the Aristo cars and metal wheel sets.

Based on what I experienced, I suggest the following improvements to Aristo's floor assembly:

Given the premise that it is more difficult for the hobbyist to remove material in an even fashion, it is best to start with an optimal ribbed wall height for cars equipped with metal wheels that sit lower than the ones with standard plastic wheels.
Therefore, reduce the present Kadee pad wall height by 0.040 inch as I found necessary to do in order to obtain the proper Kadee 880 coupler gauge alignment.
I measured wall height to be 0.150 inch tall - thus, 0.150 - 0.040 = 0.110 inch tall for the new height (e.g. new depth).

Comment: making the wall height slightly lower than 0.110 inch may be considered, too, as Kadee now has a shim product (Kadee 841) to be used with their 830 product.
See below link for:
"#841 & #941 Gear Box Shim For Kadee® G-Scale #830 & #930 Couplers"
Kadee 830 coupler box shims

Keep the present Aristo Kadee pad shape, hole, and wall locations intact that results in a projected coupler draft gear box to accommodate those cars that would emulate prototype cars having "Hydra Cushion" as in SP use, or "Shock Control" - as in Santa Fe. (Other railroads may have different names for the same or similar technology used to prevent freight damage.)

As illustrated with red in the below picture, ADD a group of four (4) new holes (that correspond to the Kadee 830 coupler box holes) like that of the present floor holes' geometry but with an offset 0.400 inch inboard toward the truck bolster of the car.
Only have factory holes for the bottom black part of the floor assembly - NOT the brown floor board area.

If choosing to mount a Kadee 830 box using its two center axis holes, it is advantageous (for support reasons) that Aristo consider extending the floor pad ribbed walls by an additional 0.400 inch inboard toward the truck bolster; otherwise, a user added spacer will have to provide coupler box support at the hole closest to the bolster.
However, the simpler, better approach is to mount the Kadee box using its other two outboard holes.

Let the user drill out the brown floor board area to accept #4 size self threading screws (or Kadee provided #2-56 machine screws & nuts) - based on preference. This will reduce factory costs as only the bottom black part of the floor assembly need be updated.

Shown below is the Kadee 830 box straddle mounted using only its two outboard holes with #2-56 screws & nuts. Note how it's quasi centered over the ribbed walls; hence, facilitating a balanced attachment.
Thus, only two screws are required to secure the box to the floor of the car, rather than three screws if the box were to be mounted in original Aristo factory projected position.

Shown below is the upper brown floor board area with Kadee 830 box mounted with its two supplied 2-56 screws and nuts. Note the third hole shown to the left is not needed for straddle mounting the box.

Item 3 should allow for a flush mount bulkhead end Kadee 830 box installation that is more prototypical for the era of the 40 foot freight cars. The picture below shows the example car with flush mount Kadee 880 box having 0.040 inch trimmed down coupler pad wall ribs.

If a user so chooses to take advantage of this location it will be understood that one of the  bolster tangs on the trucks will require it be cut short / removed so as not to interfere with the back end of the installed Kadee 830 box. Since the newer Aristo production run floor assembly accommodates the long tang of a truck when it is installed 180 degrees (less coupler) the short tang would be the better to trim off in the event one wanted to revert to a truck mount coupler.

The below pictures show an MKT (KATY) DD box car example with the added rotational clearance afforded with the Kadee 830 box now mounted prototypically being close to the car's bolster

The rotated truck from full CCW to full CW position limits as shown is greater than the original Aristo projected coupler box with its 3 point mount.

The increased position limits allows car operation on 8 foot diameter curves. Shown below is an under track view of the car on an 8 foot diameter track section.

Shown below are the two DD box car examples, both having body mounted Kadee 830 boxes with their strikers flush with car sill ends on an 8 foot diameter curve.

There is still some slight clearance between the cars when they are being pushed (in compression), too.
Shown below is the distance between the two cars on a straight track as measured in a pull state having assumed a relaxed position.

The below picture shows the cars' spacing with original Aristo truck mount knuckle couplers

Though I neglected to place the scale in the same reference spot as the previous picture, it can be seen that the cars with the Kadee flush mounted coupler boxes are about an inch closer than the cars with standard truck mount Aristo couplers.


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