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NMRA RP-20.1 (Car Weight)

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  • Member since
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Posted by Doughless on Wednesday, February 22, 2023 7:49 AM

ATLANTIC CENTRAL

Douglas, do the wheels on a Chevy fit a FORD? They do not consult each other in deciding what bolt circle or offset they will use to build their cars? Why would Athearn ask anyone else what they are doing?

BUT, more to the point, you might want to look closer.

The KADEE truck does not fit an Athearn car without modifing the car, the hole in the truck does not fit over the hub, and the HGC or metal self centering version of the Kadee truck will not work without the special hub that comes with them.

All three versions of the Kadee trucks require a flat smooth bolster with NO flange, lip, hub, which ever term you prefer.

So the first thing you do on most brands to install Kadee trucks is cut off the hub and make sure the bolster surface is flat and smooth.

Pictures at 11.

Regarding you particular issue - maybe weight is you best option.

You may have been happier modeling in a larger scale, like S or two rail O "scale", where you get more of that "intimate" feel of being around trains and they have much more "mass".

Sheldon    

 

Yeah, when I wear out the factory tires, I've upgraded the wheels on my kids cars from 17 to 18 inches...more clearence and a little safer, IMO.  While all manufacturers have the same 5 bolt pattern, the centric hubs are different sizes.  Mazda 66.1mm and Honda 64mm.   I'm sure if you ask Honda, 64mm is much better than 66.1mm. 

Why can't a Delta faucet get water from the 3/4 inch pipe into the sink with the same fitting that a Moen does?  Again, its a simple problem that should have been solved shortly after indoor plumbing was invented. 

Back in the day when I mistakenly took the bait and changed over my plastic wheels to metal on the BB, MDC, Walthers, Proto, and Accurail cars, I would always replace the trucks on the Walthers and Accurail with BB trucks, since the metal wheels I used would not fit those trucks well.  The factory screws seemed to work just fine...they didn't seem to be different..and even the BB trucks mounted onto the Accurail with the little plastic pin just fine.

Now I guess with all of these proto-specific details and fidelity that each company is producing, they have decided to change over the screw size that has worked well for 60 years.  I'm sure if you asked each company's designer/engineer. they will all swear that their way is better than the other guys' LOL.

The truth is that I doubt that many folks these days bother to switch out trucks on Genesis, Exactrail, Scaletrains, Rapido, Atlas, IM, Proto...except me because they are all too light and roll too freely...so the issue is pretty moot as far as the hobby caring about it.

- Douglas

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Posted by ATLANTIC CENTRAL on Wednesday, February 22, 2023 8:28 AM

All cars do not have the same diameter 5 lug pattern. And position of the mounting face to the edge of the rim is different on many as well.

Sheldon

    

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Posted by Doughless on Wednesday, February 22, 2023 8:54 AM

These days, most bolt patterns on FWD/AWD cars are simply listed as 114.3mm.  Honda, Toyota, Mazda, Kia, Hyundai etc.  I think even the American manufacturers use the same pattern, if they still make car-based vehicles. 

Its the little hub/axle bearing cover that is a different diameter...not the axle diameter...the COVER...by a few mms either way.  That determines the diameter of the wheel's hub, which is then covered by a little plastic piece that has the car brand's emblem on it.  If not for a different emblem and planned different hub covers, by only a few mms, most OEM aluminum wheels would fit on any FWD/AWD passenger car.  Its planned branding thing that has nothing to with function.  Function wise, all aluminum wheels are the same across all brands.

But the branding thing makes it difficult to swap wheels across brands.  That's the point I figure....controlling the product even years after its sold.

You do have to know the width and the offset of each wheel as to not rub something if you swap.  Wheels do have different offsets for asthetics and some performance issues, but performance is pretty much the same for commuter cars, so its mainly asthetics.   

Oh well, back to rolling stock weight if anybody still wants to talk about that.

- Douglas

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  • From: Maryland
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Posted by ATLANTIC CENTRAL on Wednesday, February 22, 2023 9:02 AM

Faucets - you do know you are talking to someone with 45 years of plumbing experience? 

Faucets typically have 1/2" rigid pipe thread connections, yes it looks bigger because the nominal size is based on the inside diameter of 1/2 schedule 40 rigid steel or brass pipe. But many today have flexible supply lines built in, so they often have 3/8" compression fittings to fit the typical stop valve under your sink.

What comes out of the wall can vary depending on era a type of pipe. It might be 1/2" copper, cpvc, 1/2" rigid, on the old days 3/8" rigid pipe. But typically a stop valve is placed there with a 3/8" compression outlet for a flex line to the faucet. Today braided stainless steel flex lines are made with whatever combination of fitting on each end that are required. 

Not really all that complex.

Sheldon

    

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Posted by Doughless on Wednesday, February 22, 2023 11:20 AM

I suppose that now having to crimp the standard flexible tubing has made some things more standardized.  Everything we buy is made in that big factory in China, you know, and when different companies want to have their own unique everything, the Chinese probably tell them to take a hike and they have to accept the standard product...just branded differently.

Model trains still have batches I suppose.  The factory swaps out tooling from one company to the other, so there probably is still more non-standardization in the hobby than what is in the more more consummed products.

NMRA weighting.  Is that a standard, or why would any company build a car that deviated from a standard weight?

- Douglas

  • Member since
    January 2017
  • From: Southern Florida Gulf Coast
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Posted by SeeYou190 on Wednesday, February 22, 2023 12:33 PM

Doughless
The truth is that I doubt that many folks these days bother to switch out trucks on Genesis, Exactrail, Scaletrains, Rapido, Atlas, IM, Proto.

I think you are correct about that.

The trucks on these freight cars are beautiully detailed, and the run well from the box. The benefits of equalization are less impactful with the high quality of track components available as well.

I also doubt that very many people are making the change.

-Kevin

Living the dream.

  • Member since
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  • From: Maryland
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Posted by ATLANTIC CENTRAL on Wednesday, February 22, 2023 8:02 PM

SeeYou190

 

 
Doughless
The truth is that I doubt that many folks these days bother to switch out trucks on Genesis, Exactrail, Scaletrains, Rapido, Atlas, IM, Proto.

 

I think you are correct about that.

The trucks on these freight cars are beautiully detailed, and the run well from the box. The benefits of equalization are less impactful with the high quality of track components available as well.

I also doubt that very many people are making the change.

-Kevin

 

I have to agree, not many people are likely to be switching out whole fleets. But Kadee and others still seem to be doing good in the replacement truck business.

Douglas, I find it very interesting how our presepectives on the world are different. You see these topics from a current point of view, model train trucks, plumbing, car wheel sizes and so on.

I see them in a complete historical progression - from where they started to now.

And, sticking to the model train aspect, I still run freight cars manufactured before I was born, so how trucks were mounted in 1950, or 1970, or 1990, is still relevant to my modeling.

Everybody copied Athearn and MDC. And by the way the owners of those two companies did talk to each other, and work together on some things. That is history I have related on this forum before.

So that is why there is some sense of a standard today. But before Athearn made their first plastic box car, the truck/bolster configuration you are familiar with did not exist.

While they may not provide exactly what you are looking for, the traditional Kadee metal sprung trucks do provide a more solid "feel" to the rolling stock as they travel along.

And while heavy equalized trucks may not be as important as they once were, I still believe they are a benefit with long trains - an area of particular interest to me considering a short train on the ATLANTIC CENTRAL is 35 cars.

And remember - the NMRA weight recommendations are not "STANDARDS". The "RP" in RP-20.1, stands for "Recommended Practice".

Sheldon  

    

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Posted by Doughless on Wednesday, February 22, 2023 8:03 PM

SeeYou190

 

 
Doughless
The truth is that I doubt that many folks these days bother to switch out trucks on Genesis, Exactrail, Scaletrains, Rapido, Atlas, IM, Proto.

 

I think you are correct about that.

The trucks on these freight cars are beautiully detailed, and the run well from the box. The benefits of equalization are less impactful with the high quality of track components available as well.

I also doubt that very many people are making the change.

-Kevin

 

Yeah, the Kadee is a nice truck, but the 2-56 screw kind of reveals what its meant for.  That screw is pretty big for how I think most OEM trucks are mounted these days.

I've never looked at the truck mounting screws for these different brands of cars.  Still, I'd be very disappointed if they each had their own different diameter screw and truck bolster mount.  What would be the point?

- Douglas

  • Member since
    January 2009
  • From: Maryland
  • 12,897 posts
Posted by ATLANTIC CENTRAL on Wednesday, February 22, 2023 8:09 PM

Doughless

 

 
SeeYou190

 

 
Doughless
The truth is that I doubt that many folks these days bother to switch out trucks on Genesis, Exactrail, Scaletrains, Rapido, Atlas, IM, Proto.

 

I think you are correct about that.

The trucks on these freight cars are beautiully detailed, and the run well from the box. The benefits of equalization are less impactful with the high quality of track components available as well.

I also doubt that very many people are making the change.

-Kevin

 

 

 

Yeah, the Kadee is a nice truck, but the 2-56 screw kind of reveals what its meant for.  That screw is pretty big for how I think most OEM trucks are mounted these days.

I've never looked at the truck mounting screws for these different brands of cars.  Still, I'd be very disappointed if they each had their own different diameter screw and truck bolster mount.  What would be the point?

 

I am puzzeled by this statement and will need to take a trip to the basement. What size screws are on what brands of newer rolling stock? I have some newer, higher end rolling stock, even some from 10 years or so ago that I have already converted to Kadee trucks - they have 2-56 screws?

I could be wrong, or maybe I'm not buying the same kind of rolling stock as you, but most of what I have has 2-56 truck screws?

The point of using a 2-56 screw - how about compatiblity with most of the HO trains built in the last 70-80 years?

Sheldon

 

    

  • Member since
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Posted by ATLANTIC CENTRAL on Wednesday, February 22, 2023 8:42 PM

So, I just happen to have three brand new Rapido F30D undecorated flat cars up here in my office. So I unpacked one and removed the truck screw.

The instructions clearly indicate the size of the screw - it is an M2 x 4mm.

 

An M2 screw, designed for a 2mm clearance hole, is actually 1.88 mm in diameter, or 0.074"

A SAE 2-56 screw is 0.082" in diameter.

All measurments confirmed with a digital micrometer.

The trucks on this high end Rapido car don't look much different than the trucks on Athearn cars I bought four decades ago, except for a little brake shoe detail that is not as good as the brake shoe detail on the Kadee truck.

Pretty sure 2-56 or its metric equal still rules the truck attachment world.

Sheldon

    

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Posted by Doughless on Wednesday, February 22, 2023 9:05 PM

ATLANTIC CENTRAL

 

 
Doughless

 

 
SeeYou190

 

 
Doughless
The truth is that I doubt that many folks these days bother to switch out trucks on Genesis, Exactrail, Scaletrains, Rapido, Atlas, IM, Proto.

 

I think you are correct about that.

The trucks on these freight cars are beautiully detailed, and the run well from the box. The benefits of equalization are less impactful with the high quality of track components available as well.

I also doubt that very many people are making the change.

-Kevin

 

 

 

Yeah, the Kadee is a nice truck, but the 2-56 screw kind of reveals what its meant for.  That screw is pretty big for how I think most OEM trucks are mounted these days.

I've never looked at the truck mounting screws for these different brands of cars.  Still, I'd be very disappointed if they each had their own different diameter screw and truck bolster mount.  What would be the point?

 

 

 

I am puzzeled by this statement and will need to take a trip to the basement. What size screws are on what brands of newer rolling stock? I have some newer, higher end rolling stock, even some from 10 years or so ago that I have already converted to Kadee trucks - they have 2-56 screws?

I could be wrong, or maybe I'm not buying the same kind of rolling stock as you, but most of what I have has 2-56 truck screws?

The point of using a 2-56 screw - how about compatiblity with most of the HO trains built in the last 70-80 years?

Sheldon

 

 

Sheldon, the problem appears to be with the "2-56" screw supplied with the Kadee trucks.  They are silver and a bit wider than the holes in the Atlas, Exactrail, and Athearn RTR cars I tried to fit them into.  (They look like MDC/BB screws).  The screws that came with those cars are black, and while they are close, they are narrower than the Kadee silver screw, or have a finer thread (the Kadee screw stuck in each.  I could have "cut" its thread into the styrene if I forced it with a firm fist and twist).

Maybe there is a slight difference in what China calls a 2-56 and what an American made 2-56 is.

The Athearn RTR, Exactrail, and Atlas trucks do not mount well onto each others' cars.  While the screws appear to be the same diameter, the Exactrail has a built in washer to its head making it not possible to fit into the Athearn RTR truck very well, and visa vers.  The Atlas screw has a different shape altogether than either the ER and Athearn, sort of tapered. 

Based upon my crude 20 minute experiment, none of the trucks are interchangeable with each other, but they are close enough that they could be made to fit.  Its not like the old MDC/BB trucks that were interchangeable, and slid onto the Accural kit cars (they had bad trucks and wheels).  IIRC, the accurail press fit pin would also hold the BB/MDC truck, but my memory may be wrong about that, and it may have needed a red Kadee fiber washer to help.

Interestingly, both Exactrail cars have trucks that have a form of flexible equalization...didn't know this until now.  They are one part trucks that mount on a flange on the car body, whereas the Kadee truck is a two-parter than needs the flange removed, if I understand it correctly.

Again, most of this is a pointless experiment because folks aren't going to be swapping out trucks on these higher end cars.  

- Douglas

  • Member since
    January 2009
  • From: Maryland
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Posted by ATLANTIC CENTRAL on Wednesday, February 22, 2023 9:44 PM

Douglas,

Again some of these newer cars may have M2 screws, not 2-56 screws, very slightly smaller.

I have no Exactrail cars.....

I only have few older Atlas cars....

I have lots of Athearn cars.....

And lots of Accurail cars......

And lots of Bowser cars, and TrainMinature, old Walthers, and on and on.

I do have models from Spring Mills Depot, Fox Valley, Intermountain, Kadee and likely a few others I am forgetting. 

And yes I understand what you are saying about lots of these not being interchangeable with each other. I would have never had that expectation, although I know that some of them are built to the "Athearn standard", many are not.

Again, I'm old school model trains, as nice as some of these new models are, I'm not always that impressed and I have stuff from every era of model train development from the late 40's to now. 

And for the era I model, you might be amazed how many prototypes have NOT been made by any of these high end companies in the last 10-20 years.

And you might also be surprised how good some of the older models can look with just a little work - and a new pair of Kadee trucks - just bought some more over the weekend on a four hobby shop tour of the Philly area with my grandson.

Sheldon

 

    

  • Member since
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  • From: Southern Florida Gulf Coast
  • 18,255 posts
Posted by SeeYou190 on Wednesday, February 22, 2023 10:59 PM

Doughless
I've never looked at the truck mounting screws for these different brands of cars.  Still, I'd be very disappointed if they each had their own different diameter screw and truck bolster mount.  What would be the point?

The weirdest one was the BLI NYC box car.

There was a "tube" on top the truck that went into a round slot in the car floor. The fit was very precise.

The result was a train car that would not wobble. It was an impressive bit of design.

Unfortunately, the rolling qualities of these trucks was bad, and one truck had the journals manufactured wrong so only three wheels would touch the rails. The tube made it impossible for the truck to find its own level.

I think I only have three of these. They were a pain to get converted to Kadees, and there will be no more.

-Photograph by Kevin Parson

It is a good model though.

-Kevin

Living the dream.

  • Member since
    January 2019
  • 2,572 posts
Posted by John-NYBW on Friday, February 24, 2023 5:24 AM

SeeYou190

 

 
Doughless
I've never looked at the truck mounting screws for these different brands of cars.  Still, I'd be very disappointed if they each had their own different diameter screw and truck bolster mount.  What would be the point?

 

The weirdest one was the BLI NYC box car.

There was a "tube" on top the truck that went into a round slot in the car floor. The fit was very precise.

The result was a train car that would not wobble. It was an impressive bit of design.

Unfortunately, the rolling qualities of these trucks was bad, and one truck had the journals manufactured wrong so only three wheels would touch the rails. The tube made it impossible for the truck to find its own level.

I think I only have three of these. They were a pain to get converted to Kadees, and there will be no more.

-Photograph by Kevin Parson

It is a good model though.

-Kevin

 

I have three of those lettered for the Boston and Albany and had similar issues. I hadn't looked at them close enough to figure out why so this is good information. 

This has been pretty much a lost winter as far as model railroading goes because of some family business which has been taking up most of my time. I thought I was going to make some serious headway in completing the shortline and ironing out some trouble spots on the mainline but have done nothing of consequence.

It reminds me of the saying, "If you want to hear God laugh, tell him about your plans.".

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