HW truck problems & fixes


Aristo heavyweight cars out of the box are problematic for most people.

First off, you need to realize that these are not 40' box cars, with short trucks, short wheelbases, short coupler tangs.

These are long cars and the effects of bad trackwork will be amplified as with any long car. The screwy offset pivoting of the truck makes matters worse.

So before you follow all the advice below, get your trackwork in shape, then ALL your trains will work better.

Now that the "lecture" is over, there are several design and assembly flaws that are relatively easily corrected. This page is concentrating on the newer type of truck with the transverse "rib" on top. It was an attempt I'm sure at making the situation better, but it actually made it a bit worse.

The good news, is after a few simple fixes, the "new" style will work much better, the old style can take some more effort in my opinion.

Quick fix: lubricate!

Lubricate the journals, where the truck rubs on the underbody and both of the pivot points. Use heavy gear oil or grease.

From here on, there are 2 sections, new style trucks first, then the old style.


When you go to take a truck off, notice the red wire from inside the body is on the same side on both ends. All you really need to do is remember this. I put the car on it's back, remove the 2 small screws that connect the wires from the truck pickups to the wires that go inside the body.

Take the 2 screws and washers off and remove the truck, GENTLY feeding the power wires through the hole in the truck. These wires are normally poorly soldered to the lugs, and if one feels very flexible at the joint, you would do well to resolder them. On mine, the wires were not crimped into the lugs before soldering, and the crimp that is a strain relief onto the insulated part of the wire was likewise not crimped. Definitely a future failure point. Might be best to replace them with new ones properly crimped. Soldering is optional if you do it right.

Now, you want to take one sideframe off. There are 2 screws on top, but the sideframe is also glued on! Use an xacto knife and wedge it into the middle, and then open it up enough to get a small screwdriver to spread it open.

CAREFUL! There are bosses in the plastic that you can cut off, so keep the knife AWAY from the screw holes.

Now this will not be enough to get it apart, you need to use the xacto again on the ends. You can see where there is a locating peg about 1/4" in, don't slice it off! Just get the xacto in there enough to split it open enough for a screwdriver. PLEASE, be careful, don't hold it in such a way you will jam the xacto into your hand!

Once you have popped one sideframe off, you can tilt it away enough to get the wheels out. NOTE which side is got the insulated bushing, and which side the axle is metal to metal to the wheel. You want to put the wheel back the right way. The non-insulated side always goes to the bushing that has a wire to it.

This is a good time to lube the axles. I would use a plastic compatible grease with moly in it over oil.

When you put the sideframe back on, be careful not to pop any of the four pivoting ends (for journal motion) out of their pivots. Also be sure you do not pinch the wire between the sideframe and the rest of the truck. Rule of thumb: If it does not snap back together with light finger pressure, you are doing something wrong.

Once you have replaced the 2 screws on top, then check for the nice up and down motion of the sprung journals at each corner of the truck. I squirt dry graphite/moly lube here and work the journal up and down until they move freely. Fully 50% of mine "stuck" out of the box.

Before you put the truck back on, lube the area on the underside of the floor with grease, where the ribs on top of the truck ride.

Thread the power wires through the hole in the truck, and then screw the 2 pivot screws on. These do not have to be more than gently snug, nothing rides against them when running. Then attach the power wires with the small screws, making sure the red wire is on the same side of the car at both ends.

If you do all of this, you will find a marked increase in rolling performance and much fewer derailments.

The power pickup on the cars is weird. The center axle of the 3 axle trucks is not sprung, so does not pick up power well.

On each truck, the center axle picks up from one rail, the outer 2 sprung axles pick up from the other rail. Well this would be fine if the trucks were identical, but nooo.. looking at the way it's wired, one rail is only picked up by the 2 unsprung axles on both trucks, and the other rail is picked up by the 4 sprung axles. Weird.

Well, you can swap the wheels around and even this out. An easier fix is to take 2 cars, and swap trucks between them. Be sure you don't mess up the polarity when doing this

New style trucks:

The "new" design has a transverse rib on top of the truck. This rubs on the underside of the chassis. There is NEVER any lubrication from the factory here, and a tremendous amount of friction. This, coupled with the fact that there is usually very little "side bearing clearance" (the ability to rock side to side) makes most of these cars derail on curves right out of the box. That's what happened to me, and I could not understand at first.

The picture below (most pictures courtesy Dave Goodson) shows this large and wide rib.


The first fix is merely putting grease (not oil) on the underside of the chassis where this moves.

There is an unusual design with an offset pivot, the pivot point of the truck is not at the center of the truck. This causes several issues. One issue is that the weight of the car is not distributed evenly to the truck, and tends to produce an offset force on the coupler. The best solution if your curves are wide enough is go body mount couplers. If not, observe which way your couplers are "tending" and you can remove the truck springs from one of the axles. This actually works somewhat, but I don't like it. The Arist couplers with the "override shelf" will help keep everything from uncoupling, but converting to Kadees which have no such override may create problems.

So, recommendation: If you have broad enough curves, convert to Kadees and body mount. If not, keep the Aristo couplers and run as unit train.

More lubrication!

Now the next fix involves more lubrication:

In the picture below, you see two round "bosses", that normally have a screw and washer on them. Lubricate them with grease, and be sure to lubricate the long curved slot, and check for any "sticking".

This solves most problems people have. In addition, check for free motion and enough "rocking" (fore and aft and side to side).

Design / assembly flaws and how to correct

But the picture above shows a design/assembly flaw that also accounts for these trucks not swiveling freely. Notice the boss in the curved slot has one side ground away, and the other side has excessive clearance?

Yep, there is a problem. It's hard to tell what went wrong, holes for bolster drilled wrong, or assembly jig wrong, but that boss is in the wrong place, and looks like Aristo just grinds some of it off the make up. Crazy!

So, investigating further, it's clear that the positioning of the bolster plate is to blame, since this boss is on a separate casting:


So, however that plate got in the wrong place, all you have to do is move it a bit. Since you only need to move it slightly, you have to create new screw holes:

Observe the second set of holes above the original ones. The position is really unimportant, just reposition the plate to center the bolster pin and drill new holes.


This is the way it should have been from the factory. This fix puts the boss back in the center of the curved slot where it belongs.

Increasing side bearing clearance:

Another fix, which I did not need myself, but others may, is to grind off some of the center rib to get a bit more "side bearing clearance".

The picture below is from TOC, and is pretty extreme, I have not had to do this myself when leaving the stock couplers on, but you might cut a little less off, or taper the ends of the rib rather than remove it.

This is probably more of a "cut and try". I believe you should exhaust your inspections of your trackwork first, but I present Dave's picture here for reference:


Old Style trucks:

Up until recently, I only had the new style trucks, a Santa Fe HW set, and I was diligent in getting the new trucks since I heard all the horror stories about the old trucks. In truth there are some things better on the old style, and some things worse. My building of a Napa Valley wine train netted me my first old style HW trucks (as well as my first FA diesels).

Uneven truck attitude:

Below are pictures of an early truck, and the effect of how the off center pivot and the weight of the car cause the truck to go way off level:


truck 1


This wreaks havoc when you go to other couplers since the couplers will override each other and come apart, even on straight, level track.

A fix I have implemented is to put a washer on the other pivot point, the one that rides in the arced groove in the truck, which is much closer to the center of the truck. As you can see below the truck is much closer to level.


truck 2



I was getting stringlining of the 5 car train. Granted, my small inner loop is almost all curves, with 2 sequential "S" curves with only one foot of straight track in the center.

I noticed that the cars were rocking way too much. My removal of all the parts that the truck could hit (see improving clearance section) was a douible edged sword! The trucks were often resting on plastic bits that stabilized the car body.

When I removed them, the cars were free to rock side to side. Then when I added the washer  under the "curved pivot" area, it gave clearance to the single pivot (look athe the picture above between the left and center axles).

So, I added another washer on the single pivot, but this time from the bottom of the truck. This reduces the rocking and helped pull the truck into a even more level attitude. A thick black nylon 1/4" washer from Ace hardware. Just thick enough not to add friction, but stability.

Friction! The final frontier:

Another issue was the final issue to eliminate derailments after my modification for close coupled Kadee body mounts. I was still getting random stringlining, and adding weight down low in the center of the frame helped (raised weight to about 6.5 pounds on the observation cars at the end of the train) still did not eliminate problems.

After about the 6th derailment, and putting the train back together, I noticed some cars had abnormal drag as I rolled them in or out of a curve.

What the heck? I lubed the axles, the pivots, what was going on.

Then I remembered that when looking at the wheels in the trucks, the hub of the wheel never actually touched the brass journal bearing. Weird. So I took a truck off, and from the TOP of the truck, you see the frame that holds the side frames.

There are slots in the top of the frame to let the tops of the wheels protrude through. These slots are so narrow, that the face of the wheel will rub against the plastic in this slot. Indeed I could not only see wear marks on the plastic, some looked galled/melted.

Yep, looking at the faces of the wheel, the outer rim often had black plastic smeared on it in places.

The quick fix was to put some oil on the faces of the wheels, but I will go back in there and open these areas op to clearance the wheels.

It will give more side to side play, which I think is unneeded but stop this weird friction. Probably the best thing is to grind away the plastic in the center wheelset and put some travel limiting washers in the outer axles, where much less wear was apparent. I am deducing that the center axle needs the most lateral play, and this reminds me of many people early on saying they removed the center axle to make their heavyweights run right.

I'll come back here and update after I make the mods and evaluate the results.

I'm also going to investigate the ball bearing option.

Weather Underground PWS KCACARLS78