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NMRA RP-20.1 (Car Weight)

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Posted by John-NYBW on Sunday, February 12, 2023 10:13 AM

ATLANTIC CENTRAL

When Kadee first switched to installing the semi scale coupler on their rolling stock, it was possible to purchase the older original head version and replace them. I bought a reasonable stock of those couplers for just such occasions, although to this date I only have a small roster of Kadee rolling stock. They have since discontinued the original head version of the coupler that fits their rolling stock.

I replied to Kevin's post before reading yours. I see now the larger head couplers are no longer available for Kadee rolling stock. Do you have enough of those couplers in stock that you could sell me a pair of them for my Kadee D&H boxcar? If not, can you give me the number of the coupler. I might be able to find it on ebay.

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Posted by John-NYBW on Sunday, February 12, 2023 10:03 AM

SeeYou190

 

 
Doughless
Kadee Cars makes rolling stock.  Those are high quality assembled, high detailed cars with their semi scale couplers installed, and metal wheels that are actually dark colored so that they look real (like plastic wheels).  Thing is, their rolling resistance is pretty high, making them great cars for smaller layouts. Semi-scale couplers with more rolling resistant trucks right out of the box.  Great company.   

 

Kadee undecorated tank cars and covered hoppers only came with semi-scale couplers.

These cars have a unique coupler shank and are not easily converted to other Kadee couplers.

I wrote to Kadee after purchasing a couple of these, and Sam helped out. He told me a "full size" head coupler is available for customer conversions where people do not want the semi-scale coupler.

I placed an order, and now all my cars have full size coupler heads.

-Photograph by Kevin Parson

Yes, Kadee is a great company.

-Kevin

 

That's good to know. I bought a Kadee Delaware & Hudson Boxcar about five years ago. I think it was at a discount due to being part of an estate sale. When I discovered it was a semi-scale, I attempted to replace it with a #148 and realized it wouldn't work. I'm glad to learn there is a large head option because that highly detailed car has been in a storage drawer ever since. Do you remember the number of the replacement coupler. 

The term "semi-scale" reminds me of a George Carlin routine about contradictory terms. It's like semi-boneless ham. How can that be? Does it have a bone in it? Then it's a bone-in ham. Plastic glass is another one. And why do we drive on parkways and park on driveways?

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Posted by ATLANTIC CENTRAL on Sunday, February 12, 2023 10:00 AM

Doughless

 

 
SeeYou190

 

 
Doughless
Kadee Cars makes rolling stock.  Those are high quality assembled, high detailed cars with their semi scale couplers installed, and metal wheels that are actually dark colored so that they look real (like plastic wheels).  Thing is, their rolling resistance is pretty high, making them great cars for smaller layouts. Semi-scale couplers with more rolling resistant trucks right out of the box.  Great company.   

 

Kadee undecorated tank cars and covered hoppers only came with semi-scale couplers.

These cars have a unique coupler shank and are not easily converted to other Kadee couplers.

I wrote to Kadee after purchasing a couple of these, and Sam helped out. He told me a "full size" head coupler is available for customer conversions where people do not want the semi-scale coupler.

I placed an order, and now all my cars have full size coupler heads.

-Photograph by Kevin Parson

Yes, Kadee is a great company.

-Kevin

 

 

 

That's a great looking model Kevin.

Yes, I have several of those exact covered hoppers factory painted for the FEC and Central of Georgia for when I want to run older era trains

From my experience, those cars....at least the several I have, cant speak for every car Kadee has made.... have more rolling resistance than the typical new car produced by other manufacturers.  They switch well, stock, right out of the box with their semi scale couplers.  But I don't know how well they would work for building a 50 car train traversing a 2% grade.  I suppose others would swap out the trucks or wheels.

Too bad Kadee doesn't make contemporary era models, or they would be my go to source for rolling stock.

Edit:  I see Sheldon explained basically the same thing, so my response to him would be repetitive.  And his solution is to modify (work-around) the standard kadee truck/wheelset issue.

 

They make their trucks in every type and style for every era. And they offer semi scale wheelsets. In fact the HGC trucks can be purchased with code 88 wheeelsets installed. Changing trucks seems easier and more effective than adding weight.

And even with your switching theme, you may see benefits to equilized trucks.

Sheldon

    

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Posted by Doughless on Sunday, February 12, 2023 9:43 AM

SeeYou190

 

 
Doughless
Kadee Cars makes rolling stock.  Those are high quality assembled, high detailed cars with their semi scale couplers installed, and metal wheels that are actually dark colored so that they look real (like plastic wheels).  Thing is, their rolling resistance is pretty high, making them great cars for smaller layouts. Semi-scale couplers with more rolling resistant trucks right out of the box.  Great company.   

 

Kadee undecorated tank cars and covered hoppers only came with semi-scale couplers.

These cars have a unique coupler shank and are not easily converted to other Kadee couplers.

I wrote to Kadee after purchasing a couple of these, and Sam helped out. He told me a "full size" head coupler is available for customer conversions where people do not want the semi-scale coupler.

I placed an order, and now all my cars have full size coupler heads.

-Photograph by Kevin Parson

Yes, Kadee is a great company.

-Kevin

 

That's a great looking model Kevin.

Yes, I have several of those exact covered hoppers factory painted for the FEC and Central of Georgia for when I want to run older era trains

From my experience, those cars....at least the several I have, cant speak for every car Kadee has made.... have more rolling resistance than the typical new car produced by other manufacturers.  They switch well, stock, right out of the box with their semi scale couplers.  But I don't know how well they would work for building a 50 car train traversing a 2% grade.  I suppose others would swap out the trucks or wheels.

Too bad Kadee doesn't make contemporary era models, or they would be my go to source for rolling stock.

Edit:  I see Sheldon explained basically the same thing, so my response to him would be repetitive.  And his solution is to modify (work-around) the standard kadee truck/wheelset issue.

I hope Kadee continues to make the more resistant rolling truck/wheelset.  They work better than the standard combo so many other manufacturers use.

Of course, for my contemporary era, I would need 36 inch wheels.

- Douglas

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Posted by ATLANTIC CENTRAL on Sunday, February 12, 2023 9:37 AM

SeeYou190

 

 
Doughless
Kadee Cars makes rolling stock.  Those are high quality assembled, high detailed cars with their semi scale couplers installed, and metal wheels that are actually dark colored so that they look real (like plastic wheels).  Thing is, their rolling resistance is pretty high, making them great cars for smaller layouts. Semi-scale couplers with more rolling resistant trucks right out of the box.  Great company.   

 

Kadee undecorated tank cars and covered hoppers only came with semi-scale couplers.

These cars have a unique coupler shank and are not easily converted to other Kadee couplers.

I wrote to Kadee after purchasing a couple of these, and Sam helped out. He told me a "full size" head coupler is available for customer conversions where people do not want the semi-scale coupler.

I placed an order, and now all my cars have full size coupler heads.

-Photograph by Kevin Parson

Yes, Kadee is a great company.

-Kevin

 

Kevin, so funny, I was covering that same situation in my long more detailed post.

Sheldon

    

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Posted by ATLANTIC CENTRAL on Sunday, February 12, 2023 9:29 AM

Douglas,

Interesting that you bring up the Kadee rolling stock and the rolling qualities of the stock Kadee sprung truck with its plastic axles.

Two interesting points that fit right into this descussion.

Couplers - when Kadee first got into the rolling stock business, their cars came with the standard head coupler. If you have never had reason to disassemble a Kadee car, you might not be aware that their rolling stock uses a unique coupler shank, not one of their other standard designs.

When Kadee first switched to installing the semi scale coupler on their rolling stock, it was possible to purchase the older original head version and replace them. I bought a reasonable stock of those couplers for just such occasions, although to this date I only have a small roster of Kadee rolling stock. They have since discontinued the original head version of the coupler that fits their rolling stock.

Trucks - interstingly Kadee rolling stock still comes with code 110 wheelsets.

Over two decades ago when I was on the quest for a more free rolling truck, I was already heavily invested in Kadee sprung metal trucks. So I started investigating why the Kadee truck was not as free rolling as other trucks.

I will not go deeply into the science right now, but replacing the wheelsets with Intermountain wheelsets, which have a smaller diameter axle projection outside the wheel, turned the somewhat sluggish Kadee truck into the most free rolling truck I tested.

I contacted Sam at Kadee and spoke with him personally. He informed me that my science was spot on and that Kadee had always known this. And that if I wanted super free rolling trucks, I was taking the right path.

He also indicated that they were developing a new line of trucks, now available, that would be more free rolling with their wheelset. These are known today as their HGC trucks with a flexing two piece sideframe/bolster assembly.

https://www.kadee.com/shop-by-category/trucks-and-wheels/563-ho-scale-a-s-f-ride-control-50-ton-self-centering-trucks-with-33-ribbed-back-wheels-hgc

I do use these on some rolling stock, they do roll better than the sprung versions with Kadee wheelsets, but they too roll even better with Intermountain wheelsets.

So there you have it, Kadee has always known their trucks are not overly free rolling. And when I spoke with Sam he said they had no plans to discontinue the sprung trucks when the HGC trucks came out. A statement that has been proven true over the 20 year continued availability of both lines of trucks.

So, the simple fact is, I can set one of my free rolling 3-4 oz cars on level track, and gently approach it with my DC powered locomotives, and couple to it at 1-2 scale miles per hour with hardly moving the car, or without having it pushed away without coupling.

I credit the following factors:

The minimal pressure required to couple a properly installed and lubricated original head coupler.

The wider, more reliable, side to side gathering range of the original coupler.

The more reliable car centering of the code 110 wheelsets in my Kadee sprung trucks.

The high quality motor control of my DC-PWM (full voltage pulse width modulated) Aristo Craft Train Engineer throttles.

Free rolling qualities - my own tests show conclusively that my free rolling trucks allow most locos to pull as much as 30% longer trains, not just on level track, but up my 2% grades as well. A single Bachmann Spectrum USRA Heavy Mountain will pull 35 of my 4.3 oz 50' piggyback flats. Before changing the wheelsets this loco would only pull 22 of these same cars equiped with stock Kadee sprung trucks.

To conduct the desired operations, both opps sessions (including switching operations in a large yard and servicing about a dozen industries, most on a separate ISL like belt line) and display running on my new layout will require about 1000 freight cars - I already have about 900, which already have Kadee original head couplers and most already have my upgraded Kadee sprung trucks.

Way too late to change now, and not sure I would want to in any case because suitable performance would require finer scale track. (I already have the 140 turnouts for the new layout as well)

Others will choose differently.

I'm not complaining that Kadee should sell their trucks with Intermountain wheelsets because it is what I need? I pony up the money (typically about $14 a car these days) and install what I want.

Sheldon 

    

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Posted by SeeYou190 on Sunday, February 12, 2023 8:36 AM

Doughless
Kadee Cars makes rolling stock.  Those are high quality assembled, high detailed cars with their semi scale couplers installed, and metal wheels that are actually dark colored so that they look real (like plastic wheels).  Thing is, their rolling resistance is pretty high, making them great cars for smaller layouts. Semi-scale couplers with more rolling resistant trucks right out of the box.  Great company.   

Kadee undecorated tank cars and covered hoppers only came with semi-scale couplers.

These cars have a unique coupler shank and are not easily converted to other Kadee couplers.

I wrote to Kadee after purchasing a couple of these, and Sam helped out. He told me a "full size" head coupler is available for customer conversions where people do not want the semi-scale coupler.

I placed an order, and now all my cars have full size coupler heads.

-Photograph by Kevin Parson

Yes, Kadee is a great company.

-Kevin

Living the dream.

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Posted by Doughless on Sunday, February 12, 2023 8:20 AM

ATLANTIC CENTRAL

 

 
Doughless

 

 
ATLANTIC CENTRAL

 

 
Doughless

Since weight does not scale down with our models, how does the NMRA address weight of cars for switching layouts?  Or do the standards ignore them and focus on layouts that operate many trains over grades and long mainline runs...to maximize train length.  

I find that the standard weight of a car is way too light....and its wheels way too free rolling...to provide sufficient resistance when coupling.  That realistic clunk-look of two heavy objects striking each other....competing inertias so to speak.... is hard to represent.   Excessively floppy coupler springs is not the answer. IMO.

I'm skeptical that any standardized answer for what a car should weigh would not capture the diversity in our hobby.

Modern free rolling cars need more weight added to them...and maybe their axle journals stuffed with tacky glue...in order to provide the realism needed when switching...and staying put on a slight grade.  Heavier, poor-ish rolling models should still make little challenge for a modern loco to pull a 7 car train.

 

 

 

 

Interesting thought.

But my free rolling metal sprung truck cars equiped with code 110 wheels and Kadee original head couplers couple easily with a feather touch, without causing the stationary car to roll.

The Kadee semi scale coupler requires more coupling force even when perfectly aligned. And because it is smaller, it is not always as well aligned, causing it to require even more force.

While my old layout and my new layout have lots of mainline running, I also have plenty of industrial areas requiring switching. I have never had the kind of problem you are describing to any degree that would cause me to over weight cars.

In fact, many of my cars are just under NMRA RP by a 1/2 oz or so.

Again, this situation is related to the semi scale wheel and coupler issue - the degrade the performance of coupling and uncoupling.

Sheldon 

 

 

 

That's correct, semi scale couplers do not operate as freely as the normally oversized kadees. 

So if I want things to look as prototypical as I can nowadays, the harder it is to couple means I have to increase the rolling resistance of the car.  Not to mention just plain replicating the gobs of intertia two rails cars compete with as they couple  (one moving, one not) and being able to park on a ever so slight grade.  

So, IMO, for modern models with the newer semi sclae couplers, the NMRA standards might be outdated....as they apply to coupling individual cars or a small cut.  If you're coupling a cut of 20 cars to a cut of 25 cars, none of this really comes into play because there is plenty of weight (resistance) to couple with a hefty prototypical look.

 

 

 

The irony in this is that 50 years ago when I was just starting out in this hobby, there were lots of trucks with poor rolling qualities that held cars still on 1% grades, and there were working mechanical knuckle couplers that were pretty close to scale size.

 

My own choices put operation above absolute scale accuracy. And since Kadee semi scale couplers and code 88 wheels are still not to scale, why bother?

It is 1/87th scale - compromises will be made.

Sheldon

 

Yes, semi scale couplers need more rolling resistant trucks.  I'm glad to see history backing me up on that.  I didn't need it to see it, but its nice to know its out there.

In fact, operations is exactly what I'm talking about, slow speed switching ops with one or two cars.  We make personal choices that sometimes require work-arounds to overcome deficiencies in products or Standards that might be made to accomodate the majority. 

To ensure operation, you choose to always use oversized couplers. I may add tacky glue to the truck journals to add rolling resistance.  

If the NMRA recommendations, the topic of the thread, were to be set with higher weight recommendations for rolling stock, I might not need a personal work-around at all.  Too bad for me and modelers like me.

Kadee Cars makes rolling stock.  Those are high quality assembled, high detailed cars with their semi scale couplers installed, and metal wheels that are actually dark colored so that they look real (like plastic wheels).  Thing is, their rolling resistance is pretty high, making them great cars for smaller layouts. Semi-scale couplers with more rolling resistant trucks (than the norm these days) right out of the box.  Great company.   

- Douglas

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Posted by SeeYou190 on Saturday, February 11, 2023 10:35 PM

n012944
Because some of us want to be as close as possible?

As close as possible would be Proto-87, not odd looking semi-scale couplers or wide-frame-gap code 88 wheels.

Of course, Proto-87 is all custom and craftsmanship, but the accuracy matters to some people.

-Kevin

Living the dream.

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Posted by ATLANTIC CENTRAL on Saturday, February 11, 2023 10:16 PM

n012944

 

 
ATLANTIC CENTRAL

 And since Kadee semi scale couplers and code 88 wheels are still not to scale, why bother?

 

 

 

 

Because some of us want to be as close as possible?  If you are fine without trying to make things prototypically correct as possible, good for you.  Like I have always said, the hobby is big enough for both points of view.

 

I have no problem with that, long before I ever saw you on this forum I have been a big advocate for choice, for the fact that one size does not fit all, and that we all have different goals. DC or DCC, Sound or not, switching or mainline, or both, kits or RTR, or in my case both, CTC and signals (necessary in my view) or not, etc, etc.

But don't complain that your cars roll away when you try to couple them when anyone who has really tested them will agree that the semi scale couplers require more coupling force than the original head coupler, and require even more force when coupling to the original head coupler, and that they are more likely to have gathering range issues on even the best NMRA spec track.

If you are willing to accept those issues, more power to you, uses whatever you prefer.

Lots of people think I'm nuts because I use sprung metal trucks, but I run long trains, and tests have shown they track better. So yes I am also willing to give up the more realistic appearance of the truck springs to get equalization. I am however using more of the new HGC trucks from Kadee for the best of both - equalization and appearance.

I'm not suggesting anyone should do what I do, but, I'm not changing or replacing 50 years of model building either. And I'm not changing or replacing everything every time some new product comes along. 

This is a forum, people put questions or statements out there, they are going to get opinions - some based on experiance or proven facts - and, opinions, and specifc modeling goals will vary - so the best answer may be different for each person.

The things I do on this topic meet my goals. I keep car weights on the light side of the NMRA RP. My truck, wheelset, coupler and track specs allow me to do this and pull long trains with locomotives (steam in many cases) that might not other wise pull that many cars (40-50 car trains typically) up my 2% grades and around my 36"R and larger curves.

Others will have different goals.

I'm building a large layout with a 3-6 foot viewing perspective designed to showcase long trains, mainline operations, CTC and signals and a fair amount of non railroad scenic features - while still having lots of industrial switching.

I built a multi deck layout with narrow shelves only modeling the 80' on each side of the tracks - hated it before it was complete - going back to the old way.

 Sheldon   

    

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Posted by n012944 on Saturday, February 11, 2023 7:26 PM

ATLANTIC CENTRAL

 And since Kadee semi scale couplers and code 88 wheels are still not to scale, why bother?

 

 

Because some of us want to be as close as possible?  If you are fine without trying to make things prototypically correct as possible, good for you.  Like I have always said, the hobby is big enough for both points of view.

An "expensive model collector"

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Posted by John-NYBW on Saturday, February 11, 2023 7:05 PM

ATLANTIC CENTRAL

My own choices put operation above absolute scale accuracy. And since Kadee semi scale couplers and code 88 wheels are still not to scale, why bother?

It is 1/87th scale - compromises will be made.

Sheldon

 

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Posted by ATLANTIC CENTRAL on Saturday, February 11, 2023 3:41 PM

Doughless

 

 
ATLANTIC CENTRAL

 

 
Doughless

Since weight does not scale down with our models, how does the NMRA address weight of cars for switching layouts?  Or do the standards ignore them and focus on layouts that operate many trains over grades and long mainline runs...to maximize train length.  

I find that the standard weight of a car is way too light....and its wheels way too free rolling...to provide sufficient resistance when coupling.  That realistic clunk-look of two heavy objects striking each other....competing inertias so to speak.... is hard to represent.   Excessively floppy coupler springs is not the answer. IMO.

I'm skeptical that any standardized answer for what a car should weigh would not capture the diversity in our hobby.

Modern free rolling cars need more weight added to them...and maybe their axle journals stuffed with tacky glue...in order to provide the realism needed when switching...and staying put on a slight grade.  Heavier, poor-ish rolling models should still make little challenge for a modern loco to pull a 7 car train.

 

 

 

 

Interesting thought.

But my free rolling metal sprung truck cars equiped with code 110 wheels and Kadee original head couplers couple easily with a feather touch, without causing the stationary car to roll.

The Kadee semi scale coupler requires more coupling force even when perfectly aligned. And because it is smaller, it is not always as well aligned, causing it to require even more force.

While my old layout and my new layout have lots of mainline running, I also have plenty of industrial areas requiring switching. I have never had the kind of problem you are describing to any degree that would cause me to over weight cars.

In fact, many of my cars are just under NMRA RP by a 1/2 oz or so.

Again, this situation is related to the semi scale wheel and coupler issue - the degrade the performance of coupling and uncoupling.

Sheldon 

 

 

 

That's correct, semi scale couplers do not operate as freely as the normally oversized kadees. 

So if I want things to look as prototypical as I can nowadays, the harder it is to couple means I have to increase the rolling resistance of the car.  Not to mention just plain replicating the gobs of intertia two rails cars compete with as they couple  (one moving, one not) and being able to park on a ever so slight grade.  

So, IMO, for modern models with the newer semi sclae couplers, the NMRA standards might be outdated....as they apply to coupling individual cars or a small cut.  If you're coupling a cut of 20 cars to a cut of 25 cars, none of this really comes into play because there is plenty of weight (resistance) to couple with a hefty prototypical look.

 

The irony in this is that 50 years ago when I was just starting out in this hobby, there were lots of trucks with poor rolling qualities that held cars still on 1% grades, and there were working mechanical knuckle couplers that were pretty close to scale size.

 

My own choices put operation above absolute scale accuracy. And since Kadee semi scale couplers and code 88 wheels are still not to scale, why bother?

It is 1/87th scale - compromises will be made.

Sheldon

    

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Posted by "JaBear" on Saturday, February 11, 2023 1:52 PM
What should be obvious from this and past discussions is that different ffolkes have different requirements for the free rolling ability of their cars.  
Those requirements do not mean that they are wrong!
 
The problem with abbreviations is that the actual meaning can be lost. NMRA RP-20.1 expanded is, National Model Railroad Association Recommended Practice-20.1.
  
Cheers, the Bear.Smile

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Posted by Doughless on Saturday, February 11, 2023 1:32 PM

ATLANTIC CENTRAL

 

 
Doughless

Since weight does not scale down with our models, how does the NMRA address weight of cars for switching layouts?  Or do the standards ignore them and focus on layouts that operate many trains over grades and long mainline runs...to maximize train length.  

I find that the standard weight of a car is way too light....and its wheels way too free rolling...to provide sufficient resistance when coupling.  That realistic clunk-look of two heavy objects striking each other....competing inertias so to speak.... is hard to represent.   Excessively floppy coupler springs is not the answer. IMO.

I'm skeptical that any standardized answer for what a car should weigh would not capture the diversity in our hobby.

Modern free rolling cars need more weight added to them...and maybe their axle journals stuffed with tacky glue...in order to provide the realism needed when switching...and staying put on a slight grade.  Heavier, poor-ish rolling models should still make little challenge for a modern loco to pull a 7 car train.

 

 

 

 

Interesting thought.

But my free rolling metal sprung truck cars equiped with code 110 wheels and Kadee original head couplers couple easily with a feather touch, without causing the stationary car to roll.

The Kadee semi scale coupler requires more coupling force even when perfectly aligned. And because it is smaller, it is not always as well aligned, causing it to require even more force.

While my old layout and my new layout have lots of mainline running, I also have plenty of industrial areas requiring switching. I have never had the kind of problem you are describing to any degree that would cause me to over weight cars.

In fact, many of my cars are just under NMRA RP by a 1/2 oz or so.

Again, this situation is related to the semi scale wheel and coupler issue - the degrade the performance of coupling and uncoupling.

Sheldon 

 

That's correct, semi scale couplers do not operate as freely as the normally oversized kadees. 

So if I want things to look as prototypical as I can nowadays, the harder it is to couple means I have to increase the rolling resistance of the car.  Not to mention just plain replicating the gobs of intertia two rails cars compete with as they couple  (one moving, one not) and being able to park on a ever so slight grade.  

So, IMO, for modern models with the newer semi sclae couplers, the NMRA standards might be outdated....as they apply to coupling individual cars or a small cut.  If you're coupling a cut of 20 cars to a cut of 25 cars, none of this really comes into play because there is plenty of weight (resistance) to couple with a hefty prototypical look.

- Douglas

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Posted by ATLANTIC CENTRAL on Saturday, February 11, 2023 12:56 PM

Doughless

Since weight does not scale down with our models, how does the NMRA address weight of cars for switching layouts?  Or do the standards ignore them and focus on layouts that operate many trains over grades and long mainline runs...to maximize train length.  

I find that the standard weight of a car is way too light....and its wheels way too free rolling...to provide sufficient resistance when coupling.  That realistic clunk-look of two heavy objects striking each other....competing inertias so to speak.... is hard to represent.   Excessively floppy coupler springs is not the answer. IMO.

I'm skeptical that any standardized answer for what a car should weigh would not capture the diversity in our hobby.

Modern free rolling cars need more weight added to them...and maybe their axle journals stuffed with tacky glue...in order to provide the realism needed when switching...and staying put on a slight grade.  Heavier, poor-ish rolling models should still make little challenge for a modern loco to pull a 7 car train.

 

 

Interesting thought.

But my free rolling metal sprung truck cars equiped with code 110 wheels and Kadee original head couplers couple easily with a feather touch, without causing the stationary car to roll.

The Kadee semi scale coupler requires more coupling force even when perfectly aligned. And because it is smaller, it is not always as well aligned, causing it to require even more force.

While my old layout and my new layout have lots of mainline running, I also have plenty of industrial areas requiring switching. I have never had the kind of problem you are describing to any degree that would cause me to over weight cars.

In fact, many of my cars are just under NMRA RP by a 1/2 oz or so.

Again, this situation is related to the semi scale wheel and coupler issue - the degrade the performance of coupling and uncoupling.

Sheldon 

    

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Posted by Graham Line on Saturday, February 11, 2023 12:52 PM

"So just to put more mud in the waters of this discussion, how does the coupler length factor in to this weight equation?"

We measure the length of the car from one end sill to the other.  Couplers don't enter into it.

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Posted by John-NYBW on Saturday, February 11, 2023 11:11 AM

The HO standard I use is 1 oz. for ever ten scale feet of car body length. It's not that the NMRA standard is hard to calculate. I could never remember it. This standard is both easy to calculate and easy to remember. It yields a slightly heavier car than the NMRA standard but I prefer that. A 40' boxcar is 4 oz. I think by the NMRA standard it would be 3.75 oz.

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Posted by Doughless on Saturday, February 11, 2023 9:52 AM

Since weight does not scale down with our models, how does the NMRA address weight of cars for switching layouts?  Or do the standards ignore them and focus on layouts that operate many trains over grades and long mainline runs...to maximize train length.  

I find that the standard weight of a car is way too light....and its wheels way too free rolling...to provide sufficient resistance when coupling.  That realistic clunk-look of two heavy objects striking each other....competing inertias so to speak.... is hard to represent.   Excessively floppy coupler springs is not the answer. IMO.

I'm skeptical that any standardized answer for what a car should weigh would not capture the diversity in our hobby.

Modern free rolling cars need more weight added to them...and maybe their axle journals stuffed with tacky glue...in order to provide the realism needed when switching...and staying put on a slight grade.  Heavier, poor-ish rolling models should still make little challenge for a modern loco to pull a 7 car train.

 

- Douglas

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Posted by ATLANTIC CENTRAL on Saturday, February 11, 2023 7:57 AM

Never mind.

    

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Posted by Morpar on Saturday, February 11, 2023 7:22 AM

So just to put more mud in the waters of this discussion, how does the coupler length factor in to this weight equation? Should the length measurement only be the body of the car or include some portion of the couplers? When models have the longer cushioned couplers shouldn't that have some effect on car weight? I would think so since the idea is to have the weight evenly spaced throughout the length of the train to prevent tracking issues and clothes lining.

Good Luck, Morpar

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Posted by FRRYKid on Saturday, February 11, 2023 3:01 AM

gerhard_k

hmm - if that was a S-scale car, that length would be about right. But then S-scale has a different weight formula... Actually, don't get me started on the NMRA S-scale weight RP - that formula has been wrong since the beginning...  

Just as a musing I did a bit of multiplying using the scale ratios and other math figurings. I noted that S is almost exactly in the middle between HO and O. Using that idea, I almost wonder if something closer to a 2.5 or 3 oz start with 3/4 ounce for every inch would be more in line. Disclaimer: I model HO so I don't know anything about S scale other than the numbers. Just my humble opinion.

"The only stupid question is the unasked question."
Brain waves can power an electric train. RealFact #832 from Snapple.
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Posted by dbduck on Friday, February 10, 2023 4:45 PM

gerhard_k

hey dbduck - apologies - i didn't look close enough, I'm a transition-era modeler and just assumed a box car would be 40 feet - oops! 

I wonder if anyone will pick up on my S-scale weight comment... 

 

no problem, I saw the S scale comment but since I have never dealt with that scale not sure what you were referring to 

 

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Posted by gerhard_k on Friday, February 10, 2023 2:23 PM

hey dbduck - apologies - i didn't look close enough, I'm a transition-era modeler and just assumed a box car would be 40 feet - oops! 

I wonder if anyone will pick up on my S-scale weight comment... 

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Posted by dbduck on Wednesday, February 8, 2023 10:31 PM

It is a 60 foot HO box car

60' x12 = 720 prototype inches

divided by 87

720÷87=8.275 inches 

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Posted by gerhard_k on Wednesday, February 8, 2023 10:19 PM

dbduck

what I have done to make the calculation easier, I made a ruler marked off in inches however labeled each mark in "ounces" taking into consideration the 1+1/2 ounce per inch formula.

For example:: the 1" mark is labeled "1.5oz"   2" mark "2oz"   3" mark "2.5oz" all the way up to the 12" mark being "7 oz"

then all you have to do is place this ruler against a car and it will instantly tell you what the car should weigh according to the recommended practice 

as others have stated, that is the "finished" weight the car should weigh not how much to add...The amount to be added is the difference between the original weight of the car and the recommended weight of the car

 wt ruler by Paul John, on Flickr

 

As long as this topic has been revived, I'll ask the question I meant to ask 6 months ago: 

According to your ruler description of 1/2oz. per inch, the boxcar in the photo is 8 inches long. If that's an HO car, and it looks to be a 40-footer, it should be 5.5" long, as others have already said. So what am I missing here? 

hmm - if that was a S-scale car, that length would be about right. But then S-scale has a different weight formula... Actually, don't get me started on the NMRA S-scale weight RP - that formula has been wrong since the beginning... 

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Posted by dbduck on Wednesday, February 8, 2023 1:14 PM

use a "ruler" marked in Ounces...

crude but it works

 

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Posted by Graham Line on Sunday, November 6, 2022 4:53 PM

If you calculate it once, and create a chart with length on the horizontal axis and weight on the vertical axis, you will never need calculate it again.

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Posted by SeeYou190 on Friday, November 4, 2022 12:30 PM

Steven Otte
For HO scale, RP-20.1 is easy to calculate:

SeeYou190
I find the NMRA Recommended Practice way too complicated.

There are two very different points of view.

Laugh

-Kevin

Living the dream.

Moderator
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Posted by Steven Otte on Friday, November 4, 2022 8:49 AM

For HO scale, RP-20.1 is easy to calculate:

Measure the length of the car in inches. Divide by 2. Add 1. That's the recommended weight, in ounces.

--
Steven Otte, Model Railroader senior associate editor
sotte@kalmbach.com

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