Aristo-Craft Heavyweight Passenger Car 3 Axle Truck Types

Aristo-Craft Heavyweight Passenger Car 3 Axle Truck Types
April 14, 2007
Revision GE-B
Ted Doskaris

March 12, 2017
Rev. GE-C  Replaced images with higher resolution images; added REA brand info.

October 29, 2019
Rev. GE-D  Major updates: Added distinguishing material for different versions of cars & 3 axle trucks; addressed tilting truck issues brought to bear by Greg E.; added more & other info.

November 2, 2019
Rev GE-E  Added material: First version Heavyweight car wheel adjustment & Lubrication Illustrations; Car test videos

 

 

Contents:
Car Versions & Truck Types
Mitigation Fixes
Aristo's 3 Axle Truck Kit
Car Operation, Wheels, Bearings, Lube
Electrical Issues
Example Repair
Performance Results

 

 

Car Versions & Truck Types

First, A review of different version cars and 3 axle truck types will be presented.

Aristo-Craft (now defunct) appears to have produced 4 possible versions of cars and 3 types of 3 axle truck design styles for its heavyweight passenger cars with the oldest preproduction version car dating back to Aristo’s antecedent REA brand name.

The car versions, as I will define them, are as follows:

Preproduction Car Version - likely not sold to the public
First Car Version
Early Car Version
Late Car Version - includes detail evolved RPO & Baggage cars

The truck types, as I will defined them as styles, are as follows:

Preproduction Style Truck - with center point mounting, likely not sold to the public
Old Style truck - offset mount with full end axle suspension travel
New Style truck - offset mount with midpoint fulcrum rib and limited end axle suspension travel

Both old and new style 3 axle heavyweight car trucks ride on the rigid center axle with end axles spring compressed by the weight of the car resulting in all wheels touching the track railheads. The older style allows for track irregularity compliance by using its full range suspended end axles without totally relying on the whole truck to rock fore & aft, whereas, the newer style relies on the rocking action of the whole truck about its midpoint fulcrum rib relative to the car body, augmented with minimal end axle suspension travel. None of the truck styles allow for much car side to side compliance other than fitment looseness, including what's afforded by excess intrinsic journal box wheel bearing clearances, consequently, the car can be at risk of derailing when operated on twisted track work.

 

Preproduction Car Version:

This version of the 1/29 scale car, that measures almost 30 inches end to end, appears to be the development model based on a prototype 72 foot long Central Railroad of New Jersey (CNJ) "Blue Comet" car . (Different Blue Comet prototype cars could have 2 axle or 3 axle trucks.)

To wit, Aristo's manual for the combine car states its "...based upon a design of the Bethlehem Ship- Building Company and built for the Central Railroad of New Jersey/CNJ in early 1920s".

The preproduction car had features that were not on succeeding version cars. Among other things, it had the oldest Aristo 3 axle truck type. In the end, the succeeding car versions offered in Coach, Diner, Observation, RPO, Baggage, and Combine (and derivative Doodlebug) had compromises incorporating features that would include both older (e.g. truss rods more common to wood side cars) and newer prototypes, either with 2 axle or 3 axle trucks.

Illustrated below is a picture of an Aristo-Craft antecedent REA brand Heavyweight car with 3 axle trucks.

When examining the REA car picture, its truck appears to only have a center mount attachment to the car body. This is unlike succeeding designs since about the mid 1990s where the heavyweight car 3 axle trucks are offset mounted to the car's bolster. It is not known if cars having center mount trucks were actually made available for sale, but it's unlikely.
The truck offset mounting method is similar to that of the Aristo U25B loco except the loco includes rollers to minimize pivot friction.

By offset mounting the trucks, when the car is traversing curves, the result would be to minimize coupler projection overhang of the car toward the outside curve rail with the trade-off of more belly overhang over the inside curve rail. Given the relatively long length of the car, this method appears to be helpful for operation on tighter diameter curve tracks being beneficial for positioning of truck mount couplers and definitely when choosing to body mount couplers.

First Car Version (packaged in silver / gray boxes, possibly some in black boxes):

This version car has offset mounted trucks (truck pivot not centered), and the trucks are fitted with wheels having insulated axle sleeves; consequently, power pickup used for interior lighting is at each wheel on a track powered system. Illustrated below is an example First Version car.

The trucks on this version car have a rigid unsprung mounted center axle with a suspension system having springs for outboard swing axles. The intent is for the truck to not rock up and down very much to conform to track irregularities, but for its end axle suspension to do the work. However, owing to the truck offset mounting, when the car is on the track, the truck is typically tilted downward toward the end of the car with the spring loaded end axle nearest the end of the car compressed more than the opposite axle facing toward the center of the car. The truck does not allow for much car side to side compliance other than fitment looseness, including what's afforded by excess intrinsic journal box wheel bearing clearances, consequently, the car can be at risk of derailing when operated on twisted track work.

As to the car itself (including succeeding versions), the roof is smooth, has clerestory "skylight" windows and vents, and vestibules with step risers that flare outward down toward the track. Brass truss rods are supplied for user installation. Trucks have very long tangs with Aristo's knuckle couplers attached.
Build quality on the first version car is poor compared to succeeding versions (e.g. vestibule steps crooked, paint and lettering can be below par.)

Early Car Version (packaged in black or yellow boxes):

This version car, like the first version, has offset mounted trucks (truck pivot not centered), but the trucks are fitted with semi insulated wheels (only one wheel electrically insulated on a metal axle); consequently, power pickup used for interior lighting is now at only 3 of the 6 wheels on a track powered system. Illustrated below is an example early version car.

This early version car, also, has access holes near its underbody ends in which to place a long shank screwdriver to make it easier to unfasten or fasten the roof.

Aside from the different wheels and associated electrical wiring within the truck, the early version car suffers from the same tilting truck malady as the first version car. See below illustrations:

The reason for the truck tilt can be seen in the illustration below.

Late Car Version (packaged in yellow boxes):

This version keeps the rigid mounted center axle and semi insulated wheels like the early version but changes both the car and truck bolster design such that the weight of the car is now placed on the center of the truck rather than offset toward the end of the truck, thereby, resolving the truck tilt problem of prior versions. This is done by incorporating a rib at midpoint across the top of the truck bolster from sideframe to sideframe. The rib serves as a bearing against the surface of the redesigned car bolster. The truck now is intended to rock up and down evenly at this fulcrum midpoint rib - no longer completely relying on is end axle suspension to conform to track irregularities. Accordingly, the area below the sideframe journal boxes now has a tab that limits the downward suspension travel toward the track. This resembles what was done on Aristo's ALCO locomotive 2 axle truck sideframes when its suspension design was eliminated for the rigid mounted ball bearing motor blocks.

Another distinguishing difference between the late version and earlier version car is illustrated below.

Worth mentioning, but not pertaining to the car's trucks, is specific to the RPO and Baggage cars - illustrated below.

It's likely other type heavyweight late version cars evolved to receive the flexible diaphragms, too.

Mitigation Fixes - for problems with different version cars:

Common to all fixes is the use of washers. Preferable washers are made of Nylon type plastic for their intrinsic slippery nature, but metal washers can be used. For applications requiring stacked washers, a thicker washer can be used. Nylon type washers and example sources to obtain them are described below.

Suggested Hardware Needed:

Digi-Key, Part Number: 36-3138-ND

 

The "Midwest Fastener" Box of Mylar Washers shown below is obtainable from retailer, Monster Fastener

Illustrated below is the relationship of selected washers used.
Note that some cars may have different diameter & finish factory metal washers and / or different length factory truck mounting screws than shown below.

The purpose of the small washer shown above is to allow the fastening screw to be tighten without causing binding against the truck. The truck must be free to rotated without restriction. If the small washer is not used, the mounting screw will have to be a bit loose.

First Version Car Truck Tilt:

Note: The "fix" for the first version and early version car that follows later is virtually the same.

Illustrations showing two options will follow, but to summarize:

First, install one thin washer on the chassis bolster sliding slot post
Put the truck over both chassis posts
Put washers over pivot post that extends somewhat beyond the truck
Fasten truck to chassis with factory metal washers using factory screws

Two options are illustrated.

Note: For option 2 illustrated below, be sure to use the thin washer on the sliding slot post before the truck is installed.

Early Version Car Truck Tilt:

Illustrated below is what is to be done.

Note: The "fix" for this early version car is virtually the same as for the first version car with like kind results.

Illustrated below is the result of what was done to mitigate tilting trucks.

Late Version Car - Limiting truck rocking:

The late version car does not suffer from tilting trucks like predecessor versions, however, the truck could rock enough to interfere with protruding chassis bosses.

Another issue with the late version car can be ill fitting, tilting, chassis bolster which should be remedied before limiting the truck rocking - illustrated below.

Illustrated below is the "fix" to limit the amount of truck rocking using washers differently than predecessor versions to limit the amount of rocking to an acceptable range.



A couple of example cars used to illustrate the trucks will be shown with larger pictures:

Described and shown is a comparison of the newer late version Heavyweight, ART-31610, 2005 made SP RPO and the prior early version, ART-31609, 1996 made D&RGW RPO cars. The primary difference of these cars is associated with their 3 axle truck design as previously described.


The RPO and Baggage cars are unique because they don't have a vestibule ends with steps, but otherwise don't differ from other heavyweight cars as to their version.

The below picture shows the Aristo-Craft early version D&RGW RPO car of 1996 production date and the late version SP RPO car of 2005 production date with the baggage end view comparison. Note the brake wheels are on both cars.

The below picture shows the SP RPO car and D&RGW RPO car post office end view comparison with the extra brake wheel on SP car only! I suspect the prototype only had one brake wheel.


Below is the new SP RPO car and older D&RGW RPO car top view that serves to compare the 3 axle truck coupler tang projection differences. Note the then new shorter and more realistic SP version.

 

 

Aristo's 3 Axle Truck Kit


Below is the Aristo-Craft ART-29103 3 axle truck replacement kit. This particular example is of the older, long coupler tang.
I used these to retrofit my Napa Valley Wine Train cars that originally came with 2 axle trucks. The kit includes one axle as it is meant to transplant the remaining axles from the 2 axle truck that can be seen to the right side of the picture.

Note: When using the Aristo's ART-29103 3 axle truck kit - that comes in truck pairs inclusive of only one wheel assembly per truck - it is intended that the 2 wheel assemblies be removed from the original 2 axle trucks and transplanted into the 3 axle truck assembly. (Since Aristo-Craft had redesigned its heavyweight car trucks and corresponding car bolsters from prior versions, the new design type trucks require corresponding new design type car bolsters.  Thus, attention should be afforded to what type design trucks one has as well as the design type that is in the ART-29103 3 axle truck kits. Aristo typically did not change the “ART…” identification numbers, so close inspection is well advised.)


Shown below is the older design style 3 axle truck without a fulcrum rib across the top that would be required to accommodate the newer 2005 year production run heavyweight car bolster design.

Below is the new style 3 axle truck removed from the SP RPO car showing it with a pivot rib across the top that is required to accommodate the newer production run heavyweight car bolster design.

The two pictures below show the new design style 3 axle truck installed on the car.
Note the truck's fulcrum rib as seen against the car's bolster.

The picture brightness was increased to better show the close up view of the car bolster fitment proximity.

The 3 axle truck side frames also differ:

The new design style 3 axle truck side frame includes a tab that limits the journal box travel when the suspension spring is unloaded. These limiting tabs shown facing upward are located at the bottom of each side frame journal box for the two out board axles.

Below is the old D&RGW design style 3 axle truck side frame that does not have a tab that limits the journal box travel when the suspension spring is unloaded.

Likewise, this older ART-29103 replacement 3 axle truck kit side frame design shown upside down does not have a tab that limits the journal box travel when the suspension spring is unloaded.

The D&RGW RPO old design style 3 axle truck design shown below as unloaded with the end of the car slightly lifted has no tab limited end axle suspension drop. Note no air gap under the end wheel with respect to the rail head.

Below is the SP RPO with new 3 axle truck design as shown unloaded with the limited end axle suspension drop. Note the similar size air gaps under the end and middle wheels.

Perhaps these changes to the truck owe to car derailment problems on less that ideal track work with respect to operational stresses imposed with long tang truck mount couplers.  That said, this is like what was done on Aristo's ALCO locomotive 2 axle truck side frames when its suspension design was eliminated in favor of the rigid mounted ball bearing motor blocks.

Comment: Both old and new style 3 axle heavyweight car trucks ride on the rigid center axle with end axles spring compressed by the weight of the car resulting in all wheels touching the track railheads. The older style allows for track irregularity compliance by using its full range suspended end axles without totally relying on the whole truck to rock fore & aft, whereas, the newer style relies on the rocking action of the whole truck about its midpoint fulcrum rib relative to the car body, augmented with minimal end axle suspension travel.

 

 

 

Car Operation, Wheels, Bearings, Lube

Wheel back to back Preference:

Target car operation for heavyweight cars is down to 8 foot diameter track, particularly when using Heavyweight car body mount couplers.

I found that setting the wheel back to back spacing at or close to minimum NMRA S4.3 standard is desirable for car operation through Aristo's Wide Radius turnouts.

Example of First Version and Early Version cars will be described because they have different wheel sets.

 

First Version Car - descriptions are included in the following illustrations:


More information about wheels is Illustrated below.


 

 

Early Version Car - descriptions are included in the following illustration:

 With wheels removed, the back to back spacing can be set.

 

Removing Wheels from 3 Axle Trucks:

The method for removing wheels is the same for all version trucks, however, wheel orientation matters except for the older trucks having wheels with the plastic electrically insulated axle sleeves - explained in Electrical Issues later in this vignette.
The newer ART-29111n axle / wheel types are shown in the illustration below.

 

Lubrication:

The late version SP RPO car with 3 axle truck did not come with factory lubrication, and its axles would squeak as the car was going down the track!
Molly paste is used to lube the axle tips - illustrated below.


CAUTION: Use of Aristo-Craft’s Electralube grease (CRE/ART-29602) has been associated with cracked plastic journal boxes. Do not use this product even though it may be stated in heavyweight manuals to be an optional lubricant.
Aristo-Craft has since changed to a new nylon type plastic material for its truck parts that is not adversely affected by the Electralube. However, it may be difficult to ascertain which material a given car’s trucks are made of.
Visually, the new and old material looks the same, but from my experience, the new nylon material is comparatively somewhat less flexible and somewhat harder than the older plastic material.

When mounting the truck on the car, to reduce friction, Lubriplate Lithium Grease can be used at the truck to car moving surface contact areas.


Caution: Do not get grease into screw holes of the posts for mounting the trucks.

Lubrication for areas on prior version cars would be similar except for not having a truck fulcrum rib.

 

Observations about wheels and bearings:

The wheel set axle projection tips measure 0.120 inch in diameter as shown below with the new heavyweight 3 axle truck design.

For both new and older design style 3 axle trucks the side frame brass bushings measure 0.150 inch for inside diameter. Thus, there is a great deal of slop allowing notable axle movement!

The new style shown here:

Below is the old style ART-29103 3 axle truck kit side frame brass bushings that measure the same 0.150 inch inside diameter.

The SP RPO late version car is shown in the below two pictures with the larger bolster plate design.  This larger plate includes the surface for the truck fulcrum rib to pivot against, and a wear pattern will develop due to rubbing friction. A plastic compatible lubricant can be used in this area to reduce pivot friction, but I decided to try an experiment by adding washers for a total of 0.080 inch thickness for just enough light to show between the truck fulcrum rib and the car's bolster to minimize the pivot friction and wear.


Ultimately, I decided not to add washers here but to lube the bearing surfaces because the rocking action of this newer style truck about its midpoint fulcrum rib would be disrupted.

Below is a picture of the old style, smaller size car bolster of one of my Napa Valley heavyweight cars that the older non fulcrum rib truck is meant to go with.

 

Electrical Issues

Shown in the below picture is a comparison of the undersides of the newer (late version) ART-31610 2005 made SP RPO and prior (early version) ART-31609 1996 made D&RGW RPO cars. (Both of these version cars have ART-29111n semi insulated wheels.)  Each of the trucks is factory wired the same way on the D&RGW car, whereas, they are wired differently on the newer SP car!  It appears the idea of simply making the truck wiring the same for both (all) trucks was an Aristo factory lost art!
The prior way is superior for best electrical pickup from the rails to avoid light flicker.
For trucks having ART-29111n semi insulated wheels, the propensity to have the lights flicker with the trucks wired differently on a car is due to the fact that the electrical wheel to rail pickup is via 4 wheels on one side along with 2 wheels on the other side owing to a factory foul up!  This compares to having the trucks wired the same way for a more favorable and equal 3 wheel electrical pickup on each side of the car, whereby, one truck has one wheel power pickup whilst the other truck has 2 wheel pickup.
(To wit, the evolved late version heavyweight ART-31660 2006-07 made SP Baggage car I had later received has its truck pair wired different from one-another as it should be.)
As a remedy, If you have 2 of the newer version heavyweight cars, this can be corrected by simply swapping one of the trucks to / from the cars so that they have like kind trucks as to their wiring.
If you only have one heavyweight car - as was my case - this can be corrected by swapping all 3 insulated axles end to end on ONE OF THE TRUCKS ONLY AND swapping the car's interior red / black wire connections to that truck's connections.  Only one truck should be changed this way otherwise a short circuit to track power via the car's wiring will result. (Doing this avoids having to transplant the truck side frames or electrical wiring with bushing eyelets form side-to-side on one of the trucks so it will be the same as the other truck. This could be done to fix the problem, too, but would seem to be more work to do.)

As previously stated, for one truck only, I resolved the flickering light problem by swapping the insulated end to end axle directions whilst also switching the red and black truck wire connections for the wires that originate from the car's interior. The end result is 3 wheel power pickup for each rail and no light flicker. The image on the left is the changed truck mounted to the car.


The changed truck by itself on the SP car is shown below.

More detail about the electrical aspects:

To avoid possible short circuits, one must pay attention to electrical polarity when attaching wires. Be advised that the body red wires are attached to a truck’s dedicated wire corresponding to the same side of the car (likewise for the black body wire - but on the opposite side of the car).  Moreover, I have found that the color code of the truck wires is not always consistently the same from truck to truck! So matching wire connections based on color code without some checking may cause a short.

If one were to further improve on minimizing light flickering, it appears the pickup harness with their brass bushing electrical eyelets could be transplanted from salvaged 2 axle trucks to the 3 axle truck where there are none. This augmentation would NOT add more wheel area for track power pickup, but it would make use of the axles’ shafts for an electrical conduction path to the opposite side brass bushings having the transplanted eyelets, and thus add twice the axle to bushing pickup area in the side frames.  I did not do this, however.


Example Repair - Broken Pivot Post

While working on the Baggage car a split post where the truck pivots was discovered. It's not known what caused this, but a repair was improvised using a salvaged journal bushing from an Aristo Bettendorf truck to serve as a new post.

Also, a longer mounting screw had to be used - repair illustrated below

Note: Though the example above utilizes a metric M2.5 machine type replacement screw, the screw could be slightly larger in diameter, or a self threading screw could be used, too.

 

 

Performance Results - dynamic tests

Both early and late version heavyweight cars (example RPOs) with mitigated truck mounting washers are placed as a head end car in a long heavy train behind the locos running slowly (the more critical speed) on my circuitous underhouse layout. This layout has many 10 foot diameter tracks, loops, some "S" bends and Aristo wide radius & No. 6 turnouts. All locos and all cars, including the heavyweight cars, have body mount Kadee centerset couplers.

Note: My layout track work is pretty good, but a layout with irregular track work or having pronounced grade cresting & dips or abrupt "S" bends may bring out some operational differences between the older and newer truck design styles. (Layout curves must be 8 foot diameter or greater and "S" bends must have a straight track section the length of the longest car between opposite diverging paths. Tracks must be level without vertical twists.)

 

Early Version car Tests:

The early version DR&W RPO car was first tested in the slow moving train on a straight section of track on my underhouse layout to see how the mitigated method to mount the trucks performed - illustrated below

Next, the more meaningfully test was to see how the trucks performed on the 270 degree loop back -illustrated below

 

Late Version Car Test:

The late version SP RPO car was tested in the same slow moving same train on the 270 degree loop back to see how the rocking limited truck mounting method performed - illustrated below


 

When comparing the operation on the underhouse layout of the early and late version Aristo Heavyweight cars having truck mounting mitigation, both cars performed OK without incident; however, it can be seen from the prior tests that the late version car with its factory late style truck had minimal wheel lift traversing the 270 degree loop back.

That said, when doing a "torture test" on the outdoor layout with the Heavyweight car directly placed behind the locos in the same long heavy 41 car train pulling grades & loops, the car did "string line" on one loop. That loop near the viaduct consists of a few sections of 10 foot diameter track curves with some in/out easements to the straight tracks. Granted, this would be an unrealistic test since a passenger train with far fewer cars having overall much less weight would be more prototypical.

See the car torture tested outdoors in Video:

See both early & late version cars tested outdoors in a normal passenger train without incident in Video:



End,
-Ted

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