Aristo 1st Gen Floors & Kadee Body Mounts

Aristo-Craft's first generation lowered freight car floors & Kadee body mount couplers
Ted Doskaris
December 15, 2009
Rev. GE-B - Appendix A added

An example Aristo-Craft first generation "lowered floor" that I had installed in an SP box car around the time these were first made available some years ago can be seen in the picture below.

Shown below are two examples of identical Aristo Southern Pacific 40 foot box cars that had been retrofitted with first generation lowered floors that I modified to accept Kadee 830 coupler assemblies.

Modifications included removing the rib located on the pad area at the ends of the floor and adding a 1/10 inch thick spacer (approx.) for mounting the Kadee 830s.

The car on the left is shown with Aristo Bettendorf trucks having ART-29111B metal wheels retrofitted whilst the car on the right has USAT brand Bettendorf trucks having standard USAT black metal wheels. Car height is virtually the same when using either Aristo or USAT trucks with their respective metal wheels.

The reason I tried out the USAT trucks has to do with detrimental experience upon using Aristo's Electralube lubricant within the journal box bushings. This issue was brought forth and covered at length in a thread on the Aristo General Forum sometime ago.
Since then I discovered latent Aristo Electralube damaged truck frames, so I tried using the USAT truck replacements on some of the cars just to see how they worked.

Warning: Do not use Aristo's Electralube conductive lubricant on Aristo's older production run soft plastic truck parts - even though the booklet provided with the car states otherwise.

To Aristo's credit, their newer production runs use a nylon based material that is not adversely affected by the Electralube lubricant. I noticed this material is comparatively harder and similar to what USAT appears to use in their truck parts.

Some background information

Older Aristo 40 foot type box cars, reefer cars, stock cars, gondola cars and flat cars were factory made with common floors having tall bolsters with the consequence of unrealistic rail head to car height. This is a vestige from the toy era past when the cars first came out. Since then, to Aristo's credit, the older products have made progressive, incremental improvements as newer production runs came to fruition.

One significant improvement was the design modification of the floor assembly that included shallower bolsters on which the trucks are mounted - thus, allowing a car to assume a lower to rail head stance.

Evolution of this floor design has further progressed with time as the newer version addressed mounting Kadee brand 830 type coupler assemblies (albeit, less than satisfactory) along with being able to remount Aristo trucks in a reversed position without having to cut off the coupler tang.

I had purchased about 60 or so of the first generation floors around the time they were first made available and retrofitted a like quantity of box cars, reefers, and stock cars with them.

More recently, I discovered another way to lower the cars having the original floors with the tall bolsters without having to surgically alter them or the need to purchase Aristo's lowered floors.
(In this regard, the article on the lowering the Aristo Covered Hopper cars by using modified USAT brand Bettendorf trucks can be informative - though be advised the less severe bolster design of the 40 foot cars will require slightly different truck modification values than described and shown in that article.)

That said, I have undertaken the task of equipping (including retrofitting) my train cars and locos with Kadee couplers, so the need has arisen to adapt the first generation lowered floor cars to accept Kadee 830 coupler assemblies.
Accordingly, this vignette will describe and show methods in so doing.

Floor Modifications

First, remove the floor from the car.

For information about floor R & R, see article:
Installing Aristo-Craft's lowered floor assembly in the 40 foot freight cars

As shown below the rib that is parallel to the floor bolster must be cut off of the floor pad area. I used a razor saw.

Cleaning up the pad area can be done with a file after the cut is made.

Truck Mounting Issues

Aristo Trucks
When using standard Aristo trucks (albeit with retrofitted ART-29111B metal wheels) the coupler tang must be removed from its bolster so that the installed truck will not bind against the Kadee 830 box.

Unlike the newer Aristo lowered floor, the Aristo first generation lowered floor (as shown below) will not allow installing the truck 180 degrees (with coupler removed) since it will interfere with the floor ribbing.

USAT Brand Trucks
USAT brand Bettendorf trucks will fit on the Aristo 40 foot type freight cars. If opting to use these, they can be installed 180 degrees (with coupler removed) whilst clearing the Aristo first generation lowered floor ribbing.
At first glance, it may seem the truck's tang would interfere with the brake rigging detail, but the Kadee coupler box will limit the degree to which the truck is allowed to pivot as the wheels come in contact with the box. This is the case no matter what brand truck is used.

However, the short tang must be sufficiently trimmed back or removed from its bolster so it won't bind against the Kadee 830 box. Also, a 0.032 inch thick washer should be used to minimize / eliminate car rocking when mounting the USAT trucks to the Aristo car. As shown in the above picture, I used a nylon washer with 1/4 inch hole but had to clip off the outer areas square so it would fit within the recess of the USAT truck bolster.


A spacer (shim) is required to establish the car's proper rail head to coupler height in accordance with the Kadee 880 Coupler Height reference gauge. A number of possible spacer alternatives can be used.

Spacer Alternative #1 - Using Kadee 841 Gear Box Shims

The Kadee shim must be spaced forward of the floor bolster by about a 1/10 inch so that the Kadee 830 mounted coupler box face will have the proper projected alignment with the car's end bulkhead. I used a piece of scrap plastic of this thickness as an aid as shown.

The shim must be centered within the floor pad area. A Scratch Awl tool can be used to "prick" the floor's soft plastic where the holes are to be drilled for the screws that are used to mount the coupler box.

I found that two shims are required so that the car's Kadee 830 coupler will be at the proper rail head height when using the Kadee 880 Coupler Height Gauge. Also, as shown below, the Kadee shim/s must have a hole drilled near the end in order to clear the Aristo floor mounting screw head.

The primary shim is to be 1/16 inch thick. Occasionally, adding a 1/32 inch secondary shim on top of the primary shim will work; however, most of the time this is too much. I found using a piece of roofing paper that was about 0.025 inch thick as the secondary shim worked for most cars.

Shown below is an example Aristo Union Pacific 40 foot box car with modified first generation lowered floor and Kadee 830 with Kadee 841, 1/16 inch shim, plus Roofing paper secondary shim. As can be seen, the Kadee 880 gauge is in alignment with this car's installed coupler.

Spacer Alternative # 2 - the coupler box width spacer:
I happen have a 1 inch wide by 3/32 inch thick black plastic strip purchased from TAP Plastics (costing less than $2.00) left over from what I used when lowering the Aristo covered hopper cars. (There is another article about that project.)
This spacer strip is ABS type plastic and happens to have a textured surface on one side.
I used a saw and miter box to cut sections from the strip with each not exceeding 1.35 inch in length.
The reason for this limitation is for clearing the head of the long screw that passes through the end of the floor that is used to fasten the floor at the bulkhead end of car body.

It's preferable to use glue to fasten the spacer to the floor's pad to hold it in place to make it easier for subsequent drilling of holes.

Before the glue sets up, the spacer can be located and centered on the floor pad area with the help of a machinist scale as shown below.

A Kadee 841 Gear Box Shim made it convenient to use as a template for marking the holes with a Scratch Awl tool. The template is to be positioned about a 1/10 inch forward from the floor bolster and centered over the floor pad / spacer. As can be seen in the below picture, I used a piece of scrap material from the TAP Plastic's strip butted against the bolster to establish the distance. The Scratch Awl tool can then be used to make a prick mark for each hole.

A pin vise with a very small drill bit is first used to drill pilot holes were the prick marks are made as shown below.

Complete drilling the holes using a body size 2-56 bit if you prefer using the Kadee supplied nuts - or use the tap size drill bit if you wish to thread the plastic with a 2-56 tap.

I chose to use the Kadee supplied screws and tap the holes for the 2-56 threads so I would not have to reach within the assembled car to install nuts. Shown below is what the floor with holes looks like from what would be the interior side.

Alternatively, self threading screws can be used. The Kadee 830 mounting holes will accept screws as large as No. 4, but leaving some clearance is desirable to allow for tolerances.
I found using no. 3 size wood screw like those shown below to work well.

NOTE: Because the Aristo floor has a long mounting screw at each end of the floor, you can't pre install the Kadee 830 assembly before re mounting the floor to the car body. This is because the Kadee box will block access to the hole meant for the long screw.

The floor is then re-installed in the car - paying attention to its proper orientation. (The large air tank end of the floor should be placed toward the NON brake wheel bulkhead of the car body.) Don't forget to install the two small screws that hold the sides of the car to the floor edge that are located just below the doors' opening. The heads of the long screws that hold the floor to the car body can been seen to clear the glued on coupler box spacers in the below picture.

Assemble the Kadee 830 coupler parts as per Kadee instructions.
The Kadee 830 coupler assembly can then be installed on the car floor using the supplied 2-56 screws. Kadee typically provides two screws so if you choose to use the rear hole, you will need an extra screw (brass screw shown in picture below). Mounting the coupler box only requires using the two side screws - though I found using the rear screw helpful for aligning the box.

The proper projection of the installed Kadee 830 coupler assembly is verified with the 1/10 inch thick piece of plastic as shown below.

If you choose to use the Kadee supplied screws but prefer fastening the Kadee 830 coupler assembly without threading the holes, you will need to reach within the car to place the small nuts on the ends of the projected screws and hold on to them when tightening.
Whilst this is doable for box cars if you don't have a large fist, it will be a real challenge for a reefer car having small doors. Of course, Aristo's 40 foot plug door cars would have no access at all.

Spacer Alternative # 3 - the floor pad width spacer (The preferred choice):
Instead of using a one inch wide spacer, it's actually preferable to use a spacer that covers the full width of the coupler pad area of the floor.

Drilling and tapping methods along with the spacer's length (1.35 inch) are like that previously described for the one inch example; however, there are several benefits when using the wider spacer:
Benefit 1: The wider spacer will hide the entire "scar" left from the removed rib.
Benefit 2:  It's much easer to center the spacer as all that has to be done is to align its edges with the floor pad edges.
Benefit 3:  You can pre drill pilot holes for the Kadee 830 mounting locations in the full width spacer and also stack drill several spacers in a drill press at the same time.
When one of these full width spacers is placed or glued on the floor pad, the holes could then be drilled all the way through the floor - thus, serving as a self contained template as well as a spacer. (See Appendix A for details.)

Having used up much of my 1 inch wide spacers on several cars, it became obvious the full width spacer is the best alternative, so I purchased a 1 and 7/16 inch wide by 3/32 inch thick plastic strip from TAP Plastics for use on the remaining cars. TAP Plastics will cut the strip to your specs. The cost of a 3 foot long strip was less than $2.00.

To pre drill the pilot holes in the full width spacer, start by locating and centering where the rear hole should be.
It should be located 0.2 inch from the edge of the spacer to allow for about a 1/10 inch at the back of the coupler box.

A centered Kadee 841 shim can be helpful for locating the two remaining coupler box side holes.

Using the Scratch Awl tool to prick the soft plastic in the spacer before drilling the holes is helpful.

Shown below is a Kadee 830 coupler assembly mounted over a full width floor pad spacer.

Tolerance Issues

When using the TAP Plastic spacers, I found that most of my cars attained the proper coupler height to rail head distance when checking with the Kadee 880 gauge. However, there was one car that required adding an additional Kadee 841, 1/16 inch thick spacer at one of its ends. Another car required shims at both ends thinner than 1/16 inch.

Slight height differences may also occur depending on the chosen brand of trucks used when mixed and matched with different wheel set combinations.

Car pictures

The cars shown below are virtually identical except the car on the left has USAT brand trucks and metal wheel sets whilst the car on the right has standard Aristo trucks equipped with Aristo ART-29111B metal wheels. In this example, when using the TAP Plastics spacers, I found no significant difference in the cars' coupler height to rail head when checking with the Kadee 880 gauge.  

For comparison, the below picture shows two SP box cars, both having standard Aristo trucks with metal wheels.

The black car on the right is modeled after a prototype SP "Overnight" LCL car principally used in solid sets during the 1940s on the SP Coast route between San Francisco and Los Angeles, CA. It was superceded by the "Overnight" silver / gray livery cars.

The Overnight car in the bottom of the picture shown below is an Aristo 1995 production run car. The one on the top is not dated being of an earlier production run. Both worked OK with retrofitted Aristo first generation lowered floors and Kadee 830s. (Most Aristo 40 foot type cars share the same floors and when equipped with Kadee 830s will work on track diameters of  8 foot or grater.)

Shown below is the end view of the two SP Overnight cars with Kadee 830s.
The car on the left is the Aristo 1995 production run car.

(To Aristo's credit, the two prior pictures show a noticeable improvement in the crispness of the graphics with the newer car.)

Shown below is an Aristo UP car with first generation lowered floor and Kadee 830s.

Union Pacific prototype cars included ones with painted trucks. I also painted the wheel faces.

Appendix A - Cloning coupler box spacers

It is desirable to find a way to speed up the process for turning out self made Kadee 830 coupler box spacers for Aristo's first generation lowered floors - particularly if there are many cars to retrofit.

Obtaining long length strips of black ABS plastic from a supplier to the specified width of 1 and 7/16 inch by 3/32 inch thick can be done at an inexpensive price. (I paid less than $2.00 to Tap Plastics for a 3 foot long strip.)

Cutting several of these full pad width spacers from a single strip of plastic to the same length is the first thing to do.

Stack drilling several spacers at the same time with small pilot holes can be done using a predrilled "master" spacer as a template. When spacers are placed (or glued) to the coupler box floor pad area, the holes are then to be drill for either 2-56 tap size or body size (if using nuts) depending on user choice.

Cutting the spacers

Using a miter box and hand saw can be done to advantage.
By marking the end of the box (or placing a stop) for sliding the plastic strip against, a consistent length can be cut each time. Though it may seem somewhat course to use a miter saw meant for wood, the teeth are fine enough for an effective cut.
Interestingly, I found ambient temperature influences the outcome. On warmer days (70 degrees F and greater) a razor saw can be used, but it was difficult to cut the material on cold days   On cooler days (Less than 60 degrees F) the courser saw as shown below worked surprisingly well. The sawed edges can be cleaned up with a file.

It is to be appreciated when a spacer is installed on the floor pad, the cut edges are virtually out of view. The clean "factory cut edges" of the spacers are visible as they extend to the full width of the floor pad.

In place of miter box and hand saw, a powered chop saw would be ideal to use if fitted with thin fine tooth blade or cut-off wheel.

Stacking several spacers

I used a small vise to hold a predrilled spacer as a "master" (template) placed on top of several cut spacer blanks. Since the end of the spacer with the single hole is the critical reference to the car floor bolster, putting both master and blanks in the vise whilst butting the reference end against a flat surface should be done before tightening the vise. That way the precut spacer lengths are not critical.

The purpose of the wood block is to provide a soft landing zone for the drill bit to hit when drilling.

Stack drilling the spacers

I used a very small drill bit of 3/64 inch diameter to drill the pilot holes.

Before the drill press was started, I lowered the bit into the existing hole/s of the master (top spacer in vise) as it can be difficult to see this target on the fly.

Once the plunge drilling for each of the holes was completed, the bit may need cleaning of the spent plastic sticking to it - depending on the drill's rotational speed and generated heat.

I also found the heat from the drilling process tended to bond together the stack of spacers at the hole areas - so they needed to be pried apart.

At the hole surrounds, little rings were also formed that stuck to the spacer, so they needed to but cut free with something like an Xacto knife.

The completed set of spacers with drilled holes is shown below. (The "master" that was based on the Kadee shim holes is in the center of the picture.) When drilling a stack of spacers, I kept them to no more than 3 or 4 blanks at a time so the small diameter drill would not wander.

All the "clones" turned out to be consistent.

When affixing the spacer it must be placed over the floor's coupler pad area with the edge having the single hole butted against the floor bolster. The spacer can be held whilst in place on the pad being careful not to move it whilst drilling with a 2-56 tap drill or body drill - or glued in place.
Since the spacer is made of ABS type material, it can be glued using something compatible like shown below - though a cement with black pigment may be a better choice should there be some oozing.

If gluing, avoid getting the glue near the edges of the spacer and floor pad to avoid oozing glue out of the sides.


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