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My RPO goeth where it listeth... but why doth it list and how do I fix it?

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Posted by crossthedog on Saturday, January 1, 2022 2:20 AM

@Wayne,

That split pin -- yup, that's the little bugger, alright. Thanks, doc, for persevering with your post. Better late than never. There's a lot of good info here for a future upgrade. You mention pizza-cutter wheels. I did notice that this car fairly hops when it hits the frog on the new Atlas curved turnouts. I looked to see whether the flanges were noticably deep and I couldn't really see it in comparison to the wheels of a car that rides the frog smoothly, but eventually I'll put better (metal) wheels on, too.

Happy New Year, all, and as usual, thanks for the help.

-Matt

 

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by crossthedog on Saturday, January 1, 2022 1:35 AM

@John, this all makes sense, what you say, and like I said, I'll probably get in there at some point to add some weight, but I can tell you with absolute certainty that there is nothing inside shifting around. I can twirl it over my head and behind my back like a Ninja and nothing moves in there. Remember, it was listing to one side, and then it flopped to the other side if I just tried to straighten it with my pinky. Nothing shifting. Also, the thing is so light that I'd bet dollars to donuts there has never been weight added. Which reminds me; you said Rivarossi, but surely you meant IHC. The car I have is an IHC car. (If you have a Rivarossi, then your argument against a flaw in the car design goes over the gunwhales, because the entire sample of owners known to this post -- i.e. Rich and I -- would all be experiencing the list.) But at the end of the day, I don't even have any kind of weight to put in it yet, so I'm not going to open it up today.

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by doctorwayne on Saturday, January 1, 2022 1:21 AM

Earlier today, I attempted to reply to this thread, but after an hour of trying to type suggestions and offer photo illustrations (constantly interrupted by the frozen screen syndrome), I finally completed my reply. 

When I clicked on "Submit Your Reply", my reply was apparently submitted to the trash can.

Those serrated plastic pins that were supposed to hold the trucks in place often worked themselves loose, while some the newer cars ("newer" relative to the original ones) had split plastic pins, which compressed as they were pushed into place in the underbody, the gap between them, once into the carbody, then expanded.

This picture should explain it better than my words...

Just before attempting this reply, I checked one of my boxes of passenger cars...

 

 

...and discovered that 18 of the 20 cars had been modified with screw-mounted trucks, many of the screws with large flat heads, just thin enugh to allow clearance for the trucks' axles.  I'm sure that those screwheads help to prevent listing.

Some of the others have both the car's underbody and the trucks modified to accept similar screws applied from inside the car, in a manner similar to that used on Athearn passenger cars.

When I got those passenger cars, I replaced the pizza-cutter wheelsets with Kadee 36" wheels.  They work well and require only a slight shaving of the trucks' brake shoes to prevent the wheels from jamming, using a sharp blade before the wheels are installed.

I do add weight to all of my passenger equipment, so most of them are around 8oz...  no shimmy, no shake, and no attempts at roll-overs.

Wayne

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Posted by John-NYBW on Friday, December 31, 2021 11:38 PM

I'm glad you worked out a solution. Still, I would be curious if there was anything on the inside of the car that is causing it to list. There is nothing about the car design that would cause it to list or I and every other owner of this car would have the same problem. If there is no damage to the trucks or the underbody where the truck makes contact, there is no reason the car should list. That's why I suspect there is something on the inside of the body that is out of kilter. At the very least opening up the car would eliminate that possibility if there is nothing wrong inside the car. 

Do you have a scale? If so, I would weigh the car to see if any weight has been added. Stock Rivarossi cars are terribly underweighted, especially those without interiors. They almost demand some additional weight to get them to perform adequately. I've added 1.5 oz. of weight and that only brought it up to 5 oz. That's still a bit underweight for a car of that length and mine has already had metal wheels installed. Without the weights and the metal wheels, I'm guessing this car when NIB would have weighed 3 oz. or less. Since like me, you bought yours used, you don't really know what modifications might have been done to your car. I would not only check the body of the car for any weight modifications but also the underside of the roof. Weight added to the underside of the roof would be even more inclined to cause the car to list than weight added to the floor because it would raise the center of gravity.

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Posted by crossthedog on Friday, December 31, 2021 10:59 PM

richhotrain
The problem seems to be the design of the car underbody. The point where the truck connects to the frame acts as sort of a fulcrum

Rich, I believe you are absolutely correct about this, and it seemed worth it to try to just take some of the crum out of the fulcrum, so to speak. I cut a little square of very thin plastic in the shape of the yellow outline below, with a hole in the middle so it would sit around that built up collar in the center of the truck.

I'm not exactly sure why, but it worked like a charm. The car now rides straight up and down. Maybe the plastic is contacting the nubs, but I didn't think they stood out that tall; it's difficult to see in there when the truck is back on. I did follow Overmod's suggestion of treating only the "nub-end", and that may be why the car still wiggles a lot, like it's anxious about something or giggling. It's a jumpy little car. I may eventually try adding some weight, but for now it's fine. I also need to see how the plastic does in there just freely rotating. I didn't glue it to the underframe because it was just a hare-brained swag. And since it works, I've left it alone. I may need to affix it more solidly.

@John, your cautionary tale about changing out couplers to install Kadees is noted. I may leave the couplers alone. I don't like the McHenrys but they work. And to answer your question, no... there's not a weight or anything else inside the car moving around.

-Matt

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by crossthedog on Friday, December 31, 2021 9:42 PM

John-NYBW
I have no idea why one end has the nubs and the other doesn't.

You probably missed it since these replies have come so fast, but Overmod explained earlier why nubs at only one end would make sense, at least on prototype rail cars and I guess locomotives, too. That said, I can only surmise that the nubs on the IHC model are meant to be decorative, to add realistic detail, because the truck will never touch them no matter how much the car lists, no way no how. 

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by richhotrain on Friday, December 31, 2021 7:45 PM

In my experience with the IHC passenger cars, adding weight is not a solution to the listing. The problem seems to be the design of the car underbody. The point where the truck connects to the frame acts as sort of a fulcrum, if I am using the term correctly.

Rich

Alton Junction

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Posted by John-NYBW on Friday, December 31, 2021 7:08 PM

crossthedog

@JohnNYBW, I didn't hear you mention anything about your car listing to one side. Is that not an issue with yours? I imagine they're the same model. Mine has the McHenry knucklers, so either someone upgraded (wish they'd gone with Kadees) or maybe they are of different eras, since someone here said that the production ran for a long time.

Nonprototype wheelsize bothers me not a farthing, and it sounds like switching sizes could lead to headaches, so I think I'll put in metal wheels of the same diameter.

Still waiting for rrebell to weigh in on how he added plastic to one of the bolsters.

-Matt

 

No, I do not have a listing problem. If I understand, you haven't yet opened up the car by removing the roof/glass assembly. I'm wondering if weight was added to the interior of the car and maybe has come loose and is throwing the balance off. I think you said it would list to one side or the other. That might be an indication a weight is sliding around inside. Just a guess. Removing the roof isn't easy but I was able to do it by working the tabs at one end first, then working to the middle tabs, and then the opposite end. I did break off one of the tabs in the process but the other five hold it in place. 

One problem I ran into when converting to body mounted KD couplers is that when I positioned the coupler box where I wanted for close coupling, it interferred with the swing of the truck. I had to move it about 3/16" farther forward. The screw hole I drilled comes up in the middle of the vestibule. I'll need to add rubber diaphragms to get an acceptable distance between cars. I also discovered that mounting the coupler box directly to the underside of the body results in too high a coupler. I think I need to add about a 1/16" spacer to get the correct coupler height. 

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Posted by John-NYBW on Friday, December 31, 2021 6:54 PM

maxman

 

 
crossthedog
Here's the latest report from the front. I was trying to envision how I would add something in between the bolster and the car frame to keep the car centered, and I see these two little bumps on the frame (see yellow arrows in image)... Several weird things about these little knobs. 1) They only exist at one end of the car. The other end doesn't have them. That hardly seems to matter because 2) the truck never can tilt enough to touch them. I had thought maybe they were there to prevent the listing but with the truck back in place I can rock it back and forth and it never engages the knobs.

 

A shot in the dark...but since the nubs don't contact the truck, and the other end of the car doesn't have them...is it possible that the other truck is made slightly differently and the trucks got swapped end for end?

 

I wondered about that when I was upgrading my version of the same car but the trucks are identical. I have no idea why one end has the nubs and the other doesn't. At first I thought they must have been broken off on one end but closer examination proved that to be false. 

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Posted by selector on Friday, December 31, 2021 3:50 PM

Santa Claus is waaaayyy ahead of youz. 

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Posted by maxman on Friday, December 31, 2021 3:48 PM

crossthedog
Here's the latest report from the front. I was trying to envision how I would add something in between the bolster and the car frame to keep the car centered, and I see these two little bumps on the frame (see yellow arrows in image)... Several weird things about these little knobs. 1) They only exist at one end of the car. The other end doesn't have them. That hardly seems to matter because 2) the truck never can tilt enough to touch them. I had thought maybe they were there to prevent the listing but with the truck back in place I can rock it back and forth and it never engages the knobs.

A shot in the dark...but since the nubs don't contact the truck, and the other end of the car doesn't have them...is it possible that the other truck is made slightly differently and the trucks got swapped end for end?

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Posted by crossthedog on Friday, December 31, 2021 3:44 PM

mvlandsw
Glue some shims on the truck bolster where the nubs will contact them. Maybe try some tape first to determine the needed thickness.

@mvlandsw, before Overmod's blueprint emerged, this was what I was working toward. But unless it were very very thick, such a shim would still never touch the existing nubs, so -- as Overmod prescribed -- I'll still have to raise the nubs.

-Matt

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by gmpullman on Friday, December 31, 2021 3:40 PM

maxman
Gee, I thought it was an Ebay created word. 

Real estate agents stole it first.

Cheers, Ed

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Posted by maxman on Friday, December 31, 2021 3:36 PM

crossthedog
I knew "listing" probably originated as a nautical term

Gee, I thought it was an Ebay created word. 

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Posted by crossthedog on Friday, December 31, 2021 3:16 PM

gmpullman
I used the Kadee 33" #520 smooth-backed wheel with good results:

Ed, thanks for this. That near truck is virtually identical to mine but it looks like metal, eh? Or else your weathering skills are out of this world.

@Overmod. Okay, I see you've thought this solution through carefully. I've read it several times through and I think I get it. When I think of the tiny tools it might require to manufacture such little Delrin parts and "make this on a slider" for example, I'm thinking the obvious intial answer of 'replace the trucks with better ones' doesn't seem so snarky.

Thanks guys. Looks like there is at least one solution I can pursue here. 

Also, I knew "listing" probably originated as a nautical term (and I was punning on the biblical phrase 'the wind bloweth where it listeth', which is a different word entirely meaning it blows wherever it wants to [c.f. German "Lust"]) but it never occurred to me that "catch my drift" may also be nautical in origin.

-Matt

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by Overmod on Friday, December 31, 2021 2:52 PM

mvlandsw
Glue some shims on the truck bolster where the nubs will contact them. Maybe try some tape first to determine the needed thickness.

Renember to 'pad' the whole area corresponding to truck swing, or (if all you care about is straight running) provide gentle 'ramps' at each end of the pad so the nubs won't hang up if the truck swivels too far.

You could also pad the underframe at the other end of the car and put nubs on the bolster, but that isn't as good on curves... however you might get away with putting a couple of screws in the bolster to get an adjustable ride height cheap...

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Posted by mvlandsw on Friday, December 31, 2021 2:43 PM

Glue some shims on the truck bolster where the nubs will contact them. Maybe try some tape first to determine the needed thickness.

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Posted by Overmod on Friday, December 31, 2021 2:07 PM

Go back and read the stuff I added.  Kalmbach randomly deletes anything in the composition box every few minutes so I have to type in fits and starts.

Replace or supplant the nubs with adjustable side bearings, and make a contact track on the truck frame that ensures 'level' lateral on it for any required degree of truck rotation.

Then modify the 'other end' so it swivels easily and stays precisely at ride height but can tilt in any direction.  Grease this so it doesn't just flap when it moves...

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Posted by crossthedog on Friday, December 31, 2021 1:58 PM

Overmod
The theory behind this is the same as in three-point equalization on locomotives. Here, one truck has the equivalent of side bearings, to hold the stiff carbody level, while the other one has a little play to let it twist and keep its wheels on the track while still holding up the weight. The side-bearings are 'nubs' to minimize the contact friction as the model truck swivels to go around sharp curves. Of course the immediate problem with this 'design' is that it presumes the trucks themselves provide adequate leveling support to the frame. If the axle points actually engaged the centers of the recesses a la conical bearings, this might be achievable. But if there is lateral slop it is easy to see where lateral unbalance might cause the car to tilt from 'edge to edge' if the unbalance is enough to lift the 'off side' truck frame high enough off the cone that the 'other side' of the taper gets engaged...

Astonishingly, I can actually picture all of this, and I think I just recently read about this principle somewhere -- maybe in an earlier post by you. And it makes sense that all of this would be going on at prototype level, but in an eleven-inch model I think it's clear the nubs aren't ever going to come into play, so that still leaves me with no clear path forward.

-Matt

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by gmpullman on Friday, December 31, 2021 1:45 PM

crossthedog
Nonprototype wheelsize bothers me not a farthing, and it sounds like switching sizes could lead to headaches, so I think I'll put in metal wheels of the same diameter.

I used the Kadee 33" #520 smooth-backed wheel with good results:

 Rivarossi-truck by Edmund, on Flickr

YMMV. Ed

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Posted by Overmod on Friday, December 31, 2021 1:40 PM

The theory behind this is the same as in three-point equalization on locomotives.  Here, one truck has the equivalent of side bearings, to hold the stiff carbody level, while the other one has a little play to let it twist and keep its wheels on the track while still holding up the weight.   The side-bearings are 'nubs' to minimize the contact friction as the model truck swivels to go around sharp curves.

Of course the immediate problem with this 'design' is that it presumes the trucks themselves provide adequate leveling support to the frame.  If the axle points actually engaged the centers of the recesses a la conical bearings, this might be achievable.  But if there is lateral slop it is easy to see where lateral unbalance might cause the car to tilt from 'edge to edge' if the unbalance is enough to lift the 'off side' truck frame high enough off the cone that the 'other side' of the taper gets engaged...

The snarky suggestion would be 'replace the trucks with better ones'.  In practice, use a truck tuner carefully and then spec your replacement wheelsets with the longest axle that fits without 'bottoming' in the tuned-out journal openings.

Weight the car as close to the centerline and as low down in the underframe as you can; it might make sense to carry more weight toward the 'nubbed' end.

The big point of importance is going to be nub mods.  I'd make new ones as scale-appearing 'side bearings' as far out toward the sides as will still bear on the truck frame, and have a little Delrin or similar ball or point set in the end.  I would make this on slides with a screw so it could be fine-adjusted with the chassis on the track.

Then make up an arc of a circle from thin material and glue it on each side of the truck frame, jigging as necessary to get it perfectly level to where the truck rides with the wheelset points all properly engaged and tracking.  Whether or not you keep the friction pin at the truck pivot this will ensure the thing will run level, straight or curved.

The other end, I would gin up a (shallow) ball and socket around the pivot.  This gets adjusted to precise ride height and lets the car 'heel' as necessary without 'listing', if (to continue the nautical metaphor) you catch my drift...

[Ed -- see if you can shoot him a detail drawing of the 'eyes' in Timken rods that allow lateral motion...]

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Posted by crossthedog on Friday, December 31, 2021 1:30 PM

Here's the latest report from the front. I was trying to envision how I would add something in between the bolster and the car frame to keep the car centered, and I see these two little bumps on the frame (see yellow arrows in image)...

Several weird things about these little knobs. 1) They only exist at one end of the car. The other end doesn't have them. That hardly seems to matter because 2) the truck never can tilt enough to touch them. I had thought maybe they were there to prevent the listing but with the truck back in place I can rock it back and forth and it never engages the knobs.

So... more mysteries. Why are there do-nothing knobs under just one truck?

I might be able to slip a thin piece of styrene (cut from a plant pot tag from a garden supply) athwart the car frame between it and the truck, but I suspect this would make the truck-fastening pin too short to reach in and click into place, so I would have to shave an equal amount off of the ring around the hole in the truck that I'm holding in the picture. This seems like an un-undoable and potentially disastrous action to take.

 

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by crossthedog on Friday, December 31, 2021 12:18 PM

@JohnNYBW, I didn't hear you mention anything about your car listing to one side. Is that not an issue with yours? I imagine they're the same model. Mine has the McHenry knucklers, so either someone upgraded (wish they'd gone with Kadees) or maybe they are of different eras, since someone here said that the production ran for a long time.

Nonprototype wheelsize bothers me not a farthing, and it sounds like switching sizes could lead to headaches, so I think I'll put in metal wheels of the same diameter.

Still waiting for rrebell to weigh in on how he added plastic to one of the bolsters.

-Matt

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by John-NYBW on Friday, December 31, 2021 12:08 PM

richhotrain

 

 
crossthedog

what kind of truck and wheelsets would you use to upgrade this? I use metal wheels and axles wherever I can.

-Matt 

 

 

Matt, I kept the IHC trucks and replaced the plastic wheels with IM metal wheelsets.

 

Rich

 

I would second this suggestion. The one I bought on ebay had already been upgraded with metal wheels. Just eyeballing them, they appear to be 33" wheels. I think 36" wheels might rub against the brake pads. I believe the trucks were original. They even had the truck mounted horn hook couplers. The metal wheels in the original truck roll fairly smoothly. I just had it out for the first test spin and it did OK. I have to adjust the height of the body mounted KD couplers. I also added 1.5 oz of weight. Once I get it worked out I think this will be a good addition to my fleet. 

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Posted by dknelson on Friday, December 31, 2021 11:34 AM

At one time IHC offered metal wheelsets as replacements for the passenger cars, but if memory serves the wheels were the same undersized diameter as the plastic originals, perhaps as small as 31 or 32 scale inches versus the prototype 36".   On the very similar AHM cars if you replaced the original undersized (but huge-flanged) wheels with 36" wheels with RP25 flanges, you had two immediate problems:  a cast-on brake shoe detail would rub on the wheel tread and needed to be carefully shaved smaller, and the coupler height would have of course risen a bit.  For some cars you were "lucky" because the original coupler height was too low anyway.

I also seem to recall that either IHC or AHM or maybe both offered after-market metal "pins" for holding the trucks to the bolster, pins that had slight corrugations on the shaft to give better tooth and grip the plastic hole, but with the risk that repeated removal and replacement of the metal pin would simply make the hole larger if the pin was twisted to get it out.  

Dave Nelson

 

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Posted by richhotrain on Friday, December 31, 2021 11:05 AM

crossthedog

what kind of truck and wheelsets would you use to upgrade this? I use metal wheels and axles wherever I can.

-Matt 

Matt, I kept the IHC trucks and replaced the plastic wheels with IM metal wheelsets.

Rich

Alton Junction

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Posted by crossthedog on Friday, December 31, 2021 10:51 AM

No screw, as was foretold. Plastic pin, friction mount. The pin resisted a little but I got the edge of a small screwdriver under there and it finally gave, popped out like a cork.

John-NYBW
you don't lift the car body off the chassis. You lift the roof off the car body.
John, thanks, this makes sense, but now I'm not certain I need to get in there after all. The next thing is to lean on rrebell for more details about this comment:
rrebell
You have to add some plastic to one of the bolsters.
For starters, I'm not sure what a bolster is in this context. 

For those of you who wish to prepare for the pop quiz coming up a bit later (John-NYBW, I'm looking at you), what kind of truck and wheelsets would you use to upgrade this? I use metal wheels and axles wherever I can.

-Matt

Returning to model railroading after 40 years and taking unconscionable liberties with the SP&S, Northern Pacific and Great Northern roads in the '40s and '50s.

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Posted by John-NYBW on Friday, December 31, 2021 10:15 AM

I just acquired one of these RPOs on ebay and I am in the process of upgrading it. If it is the same model as mine, and it looks like it is, you don't lift the car body off the chassis. You lift the roof off the car body. The roof and the window glass are one piece and the six clips in the bottom of the car hold that assembly to the car body and chassis which are also one piece. 

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Posted by crossthedog on Friday, December 31, 2021 10:11 AM

Thanks all. I've perused the great responses here. Will do some science later today if I can get to it, and report back. I have a feeling rrebell's comment will be germaine to the issue, but "adding plastic" will be "a whole nuther" conversation.

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Posted by rrebell on Friday, December 31, 2021 9:58 AM

You have to add some plastic to one of the bolsters. If I remember right all you had to do was pull the truck off (not easy) but since they were releised over a large time period that might just have been the run I or a freind had and they might have changed.

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