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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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My RPO goeth where it listeth... but why doth it list and how do I fix it?
Posted by crossthedog on Thursday, December 30, 2021 11:25 PM

Hey friends,

I got this very nice model of an NP RPO car at a swap meet and found when I got it home that it lists heavily to one side. Or the other. It never runs straight up and down. It doesn't fall over, it just leans. If I push it to center, it settles into a lean the other way. It's like the drunken sailor on my mail route.

I believe it to be an IHC model #40525. There's one exactly like it on a popular auction site right now, which is how I identified it. 

I thought maybe the truck screws needed to be tightened a skosh, but I can't reach or even really see them; they're hidden by the middle axle of each truck. Next I thought to remove the body from the chassis and see if the truck pops out that way, or if the fastener can be removed. But getting the body off is eluding me. I can see that there are six plastic tabs (see photo below), three on each side, but there's no way to grip the chassis and pull on it while simultaneously releasing all six tabs -- even if I had seven hands, or three hands and two agreeable friends.

How do I get this thing apart? And once I do, what should I look for in trying to fix this lean? Has anyone experienced this listing with this model before and if so, what did you do about it?

Thanks in advance.

-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 maxman on Friday, December 31, 2021 12:20 AM

Is it possible to spread the truck side frame enough to pop the center axle out?

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Posted by crossthedog on Friday, December 31, 2021 12:31 AM

maxman
Is it possible to spread the truck side frame enough to pop the center axle out?

I had hesitated because I thought I might break the truck, but yes. I got the center wheelset out and what my partial earlier glimpse had suggested was confirmed. There's no screw-head there. Just a kind of plastic grommet around some kind of pin. So it must unfasten from inside. More's the pity, as NorthBrit might say. It means I still have to find a way to bust my way inside there.

"Think you used enough dynamite there, Butch?"

-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 maxman on Friday, December 31, 2021 12:47 AM

Then you’ll need some toothpicks.  Insert one at each tab location to hold the tab away from the shell.  That should reduce the number of hands required from octopus down to human.

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Posted by crossthedog on Friday, December 31, 2021 12:51 AM

maxman
Then you’ll need some toothpicks. Insert one at each tab location to hold the tab away from the shell.

Maxman, that's brilliant. Especially since I have more toothpicks than friends.

-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 tstage on Friday, December 31, 2021 5:11 AM

The tapered ones work the best for that.  I always have them handy in my tool arsenal for that purpose, as well as convenient applicators for tiny amounts of adhesive.

Tom

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Time...It marches on...without ever turning around to see if anyone is even keeping in step.

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Posted by maxman on Friday, December 31, 2021 5:41 AM

Now that I’ve had some time to think about this, it occurs to me to ask if you are sure that what you have is really a screw.  Some of these things just have a press fit pin.   Maybe a photo with that center axle removed will elicite a response from someone more familiar with that car’s construction.

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Posted by maxman on Friday, December 31, 2021 5:44 AM

Oh, if you do try the tooth picks it is best to remove the olives first.

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Posted by richhotrain on Friday, December 31, 2021 6:49 AM

Those old IHC passenger cars all used push pins to hold the trucks to the bodies. No screws.

Rich

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Posted by nealknows on Friday, December 31, 2021 7:40 AM

If you look at the bottom of the car, you should be able to locate some plastic tabs - 2 on each side, which is what you pointed out. Push them apart (I used a small jewelers flat head screwdriver-no damage to the car) and what this enables you to do is to take the roof off, which holds the windows as well. Then you can look inside to see if someone put weights in there to car balancing. I did that to all my IHC cars as they are very light. Also, the plastic pin that holds the truck in place comes out easily. I would suggest you put in metal wheels as well. Probably 36" wheels, but you may want to try 33" as the 'brake shoe' on some of those cars inhibit the trucks to roll smoothly..

Let us know how you make out..

Neal

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Posted by maxman on Friday, December 31, 2021 8:35 AM

There you go.  Two votes for pushed in pins.  I knew someone(s) would know the easy answer.

Now, of course, your question will be “how can I tighten the pins to keep the trucks from flopping”?

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Posted by richhotrain on Friday, December 31, 2021 8:47 AM

maxman

Now, of course, your question will be “how can I tighten the pins to keep the trucks from flopping”? 

I'm not sure you can. Those older IHC passenger cars were listers, as the OP calls them. At one point, I removed the pins and replaced them with screws and washers. That seemed to work for a while, but then the listing returned. So, I went back to the pins. The underbody design seems to be the problem. I am not sure that adding weights at strategic points will solve the problem.

Rich

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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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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.

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 10:51 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 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

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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 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 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 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 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 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 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 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 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 2:52 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 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 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 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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