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Track Standards

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Posted by mlehman on Tuesday, June 16, 2020 4:35 PM

riogrande5761
Mike mentioned: "I wouldn't take a 2" difference in min R too seriously. 4" is more significant."

But it would be serious if that 2 inch increase allowed a 6-axle loco to run vs. not run on a curve 2 inches less, or other rolling stock work vs. not work.

That is true. A 2" increment could make all the difference with that specific item.

But I would suggest the only way to determine that is to run said item of rolling stock on that particular curvature and see what happens. I absolutely would not count on the mfg's declaration that it is suitable for any particular curve unless there was more than the stated 2" difference in play.

We should consider that stated curvature is usually more of an approximation than it is an exact science. Assuming the stated min R, any item that is close to it may or may not run OK. People do want to take a mfg's stated min R as a given and seem to expect utterly reliable operation at that number, when in fact we should look at such numbers as the lowest possible min R and only able to be confirmed by operation on the specific piece of track with the specific item of rolling stock of interest.

Min R doesn't really mean everything with the same stated min R will run as well as the test article did, only that it's in the realm of possibility. That frustrates some, but it's much better to understand the meaning that can be drawn from min R in regards to your design parameter than to take it as an absolute number that can be relied on and applied universally.

EDIT: To further clarify, maybe we shouldn't rely on min R but instead rely on an op R. How do I refine op R? It's a number that the majority of your rolling stock can operate on safely clear of the issues that operating at the min R might create.

Going back to my comparison between the significance of 2" and 4" worth of difference, I'd suggest a good op R would be about 4" larger radius than the min R would be. That should be enough to take care of all the variables that are encountered by pushing everything to the limit at min R, yet still expecting the same performance on the sharper track as could be achieved at larger radii.

Mike Lehman

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Posted by riogrande5761 on Tuesday, June 16, 2020 3:09 PM

carl425
 
riogrande5761
borrowing from Peter to pay Paul. Givens and Druthers as JA called them.

One of my favorite groups from the 60's - Givens, Druthers, and Mary.

 

 
riogrande5761
To stick to a 32 inch minimum radius, I had sacrifices to make, including less capacity in my staging yard, narrower pinch points etc.

 

You say that as if "32 inch minimum radius" is a line item on your "givens" list.  Maybe a better approach would be to have a "Druther" of "Run a 1938 version of The Scenic Limited" so you can understand the tradeoff you are making.  If you finish your list and only have this one train that requires a large radius, you can make a judgement call as to whether or not you want to limit the plan just to accommodate one train.

The point is that you should develop "Givens and Druthers" first in terms of scenic and operational goals, then develop your engineering standards to support them.  Arbitrarily setting a minimum radius upfront is putting the cart before the horse.

Yes, a 32" minimum radius was a line item from the start as it was on my previous layout.  Modeling focus is basically 1977-1983 and with it goes lot of long rolling stock.  In addition to several passenger trains, I have a lot of 85 and 89 foot TOFC equipment, auto-racks and 86' foot auto-parts box cars.  There are two spots where the radius is 32", and the rest are above that to one degree or another.  The longer rolling stock may not look great on those 32" curves, as MRH points out in their article, but should operate reasonably well.

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Posted by carl425 on Tuesday, June 16, 2020 12:39 PM

riogrande5761
borrowing from Peter to pay Paul. Givens and Druthers as JA called them.

One of my favorite groups from the 60's - Givens, Druthers, and Mary.

riogrande5761
To stick to a 32 inch minimum radius, I had sacrifices to make, including less capacity in my staging yard, narrower pinch points etc.

You say that as if "32 inch minimum radius" is a line item on your "givens" list.  Maybe a better approach would be to have a "Druther" of "Run a 1938 version of The Scenic Limited" so you can understand the tradeoff you are making.  If you finish your list and only have this one train that requires a large radius, you can make a judgement call as to whether or not you want to limit the plan just to accommodate one train.

The point is that you should develop "Givens and Druthers" first in terms of scenic and operational goals, then develop your engineering standards to support them.  Arbitrarily setting a minimum radius upfront is putting the cart before the horse.

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Posted by selector on Tuesday, June 16, 2020 11:16 AM

Okay, so we have come to see that, for curves, sharpness and broadness is a relative term.  It's not really what the OP has posted about.  He feels that it isn't obvious what makes Armstrong the 'dean', and I do see Byron's point that he may have been a little quick on the trigger, so quick that he shot himself in the toes.

Hopefully we have all done a good job of pointing out what makes Armstrong the figure in the hobby that so many of us claim he is/was.

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Posted by riogrande5761 on Tuesday, June 16, 2020 10:55 AM

DAVID FORTNEY

I can only dream of 30" curves. I'm restricted to 24" and maybe a inch or two above that in places. It seems the larger layouts are the only thing talked about today.

Understood.  On past posts about recommendations to layout designers with limited space, I've often suggested that any increase of radius can be helpeful, especially at low radii such as in the 18-22 inch range.  If radius can be increased by only 2 inches, it could make a difference with some rolling stock operating reliably or not.

Mike mentioned: "I wouldn't take a 2" difference in min R too seriously. 4" is more significant."

But it would be serious if that 2 inch increase allowed a 6-axle loco to run vs. not run on a curve 2 inches less, or other rolling stock work vs. not work.  Naturally increasing by greater amounts is going to yield even greater dividends, 4 inches or more.  Yes, 2 inches won't make a hill of beans difference in appearance on those curves; operation may be a different matter.

Knowing that even 30" radii has been reported as iffy for some Walthers passenger cars, I bumped up my minimum to 32" to add a bit more margin - and that in one or two spots - I've increased the curves to a bit more than that in other places - 33, 35, 36 even 40 inches.  I have a planned helix and plan to use 34" radius there. 

To stick to a 32 inch minimum radius, I had sacrifices to make, including less capacity in my staging yard, narrower pinch points etc.  Layout design is all about compromises, and sometimes borrowing from Peter to pay Paul.  Givens and Druthers as JA called them.

Also just because somebody says that my min should be 30" does not mean I should follow that advice, 24" was my limit and that is it. 

I haven't ready any messages telling anyone what they should and shouldn't do here.  Obviously if space is limited, it's going to impose restrictions that may not be able to offer any lee-way.  I've had a few occasionally tell me I should do this or that but sometimes they don't know jack.

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Posted by rrebell on Tuesday, June 16, 2020 10:42 AM

Doughless

Not sure about what Armstrong or NMRA say, its not like it matters who labels what.

For my modern era layout, I consider 30 inch radius curves to be sharp.

 

And in my world 30" is considered a very broad curve, my world is 18" radius but then my longest boxcar is 40' with only a few flat or speciaty cars being any longer (got a bunch of super detailed 36' also.

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Posted by Doughless on Tuesday, June 16, 2020 10:04 AM

Not sure about what Armstrong or NMRA say, its not like it matters who labels what.

For my modern era layout, I consider 30 inch radius curves to be sharp.

- Douglas

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Posted by kasskaboose on Tuesday, June 16, 2020 9:50 AM

There are standards and best practices.  We challenge both with different track radii.  One goal on my current (2nd) layout was running nearly any time of freight car.  That's done!  Nothing much more majestic than seeing a consist of long cars going around a broad curve. 

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Posted by BRAKIE on Tuesday, June 16, 2020 8:13 AM

Back in the day 18-22" curves was the norm for most home layouts and Athearn and other brands had short passenger cars to accomondate those curves while Walthers had scale lenght passenger car kits in the 50s as did AHM starting in the 60s.. My Dad's open  operator pit layout had "sweeping" 22" curves. I recall that because he used Walthers full lenght passenger cars.

The first long freight car I can recall was Quality Craft massive 4 truck 96' long whale belly tank car.. There may have been a long wheel based Southern Ry Tobacco barn boxcar but, I not sure. 

I do recall 18" curves started to become unpopular in the mid 60s in favor of 24-30" curves.  In fact I recall 18" curves being called "Trolly car curves" at one of the monthy Division 6 NMRA meet that feature a layout planing clinic.

Like I already mention above,if 18" is the only curve that will fit your  allotted layout space then be sure to use short cars and short wheel based locomotives.

Larry

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Posted by DAVID FORTNEY on Tuesday, June 16, 2020 1:32 AM

I can only dream of 30" curves. I'm restricted to 24" and maybe a inch or two above that in places. It seems the larger layouts are the only thing talked about today. 

I find that my 6 axle diesels run fine on 24" curves, of course they would look better on larger radius curves. Also just because somebody says that my min should be 30" does not mean I should follow that advice, 24" was my limit and that is it.  If I had 30" I would run longer longer cars , I run 50' cars with a couple of 60' sprinkled in.  You gotta adapt to the space you have and not worry about the space you don't have.

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Posted by cuyama on Monday, June 15, 2020 10:48 PM

selector
So, while you and I might be comfortable using a term like 'dean', our OP has indicated that he doesn't get it, or why that term and not another that might be more suitable

No disrespect meant, but I think that the OP understood the word “Dean” perfectly. But because the OP had done no research at all into who John Armstrong was before posting, the OP was questioning the "awarding" of the title, not the definition of it. (Edit: As I understood his post, I could be wrong)

Since our friend Random doesn't yet know who JA was (and hasn't even seen Track Planning for Realistic Operation), it seems unlikely that he would be able to suggest a better title. IMHO, of course.

Edit: And of course, it doesn't matter what we talk about here – I imagine Kalmbach will continue to use the phrase as they like. Wink

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Posted by selector on Monday, June 15, 2020 10:35 PM

cuyama

 

 

... One or two people not understanding the use of the term "Dean" is not reason enough to scramble for a different word. IMHO, YMMV, etc.

 

Byron, in my world of human conflict studies, words are important and have to have shared meaning.  Words, and constructions of several of them (idioms) fall out of favour over time and take on an 'old fashioned' feel.  Also, as a mediator and negotiator, I have accepted that sometimes part of the negotiation of understanding means finding common terms, often suggested by one or more of the parties trying to find common ground over a topic.  So, while you and I might be comfortable using a term like 'dean', our OP has indicated that he doesn't get it, or why that term and not another that might be more suitable.  While thread posts are intended for everyone to see (if they want to participate in more 'negotiaton over terms and concepts, even facts), my post was intended to elicit a response from the OP in case he feels that another term would be better.  Otherwise, there's simply no discussion, and I don't like taking that approach to a topic if I'm going to play along.  So far, though, nothing from him/her over my thoughts.

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Posted by carl425 on Monday, June 15, 2020 10:26 PM

rrinker
You have to consider WHEN Armstrong wrote his material. Both the hobby world and the prototype.

WHEN Armstrong wrote his material, there were SF and UP 4-8-4's pulling 85' passenger cars on the prototype and even more on model railroads.  I can't think of anything in daily use today that is more demanding on trackwork.

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Posted by mlehman on Monday, June 15, 2020 9:22 PM

rrinker
Space is usually the limiting factor. Few people have hangers. Everything needs to be compressed, including the track. I'd love to just do a single deck, but I can't fit what I want with 30" radius mainline curves. If I expanded that to 36", I wouldn't even get a double track in the part I'm working on now,,,

Yes, resources tend to be so finite for one's struggling line, whether mainline or somewhere out in the woods.  In the end, you need to make a choice based on what you want to model and what you want to run. Most folks do OK on the first, but then struggle with the modeled part.

I think JA's classifications were intended broadly while inspiring reflection on how one can best achieve one's goals with the hand you've been dealt.

It's when you start diuscussing how all this applies to sizing up the equipment that is desired to run that things get dicey. Everyone wants an nice direct line from some measurement stated by the mfg to a number they can cite from their layout. People want this to be a simple comparison, slam-dunk and either it works or it doesn't.

Things are rarely that simple if you play near the minimums, folks. You best leave some leeway to be certain of the layout accomodating this and that. If 24" is the bare minimum, then 26" would be better and 28" is what you need to run most 24" stuff without modification. Evene then, a run of passenger cars with lots of detail may have quite a variance in individual car models. What do you do as a mfg? You take the one requiring the widest curves and bump it a couple of inches and *presto!* you're at a comfortable 30" - where most things run OK. It's human nature to prefer to keep your options open. But if you don't really need those broad curves, then things can work quite well also with less real estate.

I wouldn't take a 2" difference in min R too seriously. 4" is more significant. In the end it's about getting specific equipment to work on track you've designed and laid. I run 28" min R on the standard gauge main, mainly because of the recognized issue of Walthers cars having issues at the stated 24" min R. Then came the CZ cars, much the same as it turned out. So good thing I left some slack, and you should, too, in designing a layout. And BTW, no I don't have room for 30" min R.

Some of the folks in the thread here have been around long enough to remember my writeup on getting my CZ cars to run reliably that I wrote up here about that experience with the first run. Yes, not perfect out of the box, but pretty darn good. With a little work, they work great. I sure wouldn't waste much effort at complaining about the min R being imperfect - or to expect a stated min R to be any more than a suggestion it is my responsibility to address.

Mike Lehman

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Posted by ATLANTIC CENTRAL on Monday, June 15, 2020 8:10 PM

Randy does make a very good point about the era in which JA wrote this book and designed many of his track plans.

The first freight cars longer than 50'-60' were the 1953 introduction of the first 75' piggyback flats. Even by the early 60's, piggybacks and auto racks remained virtually the only long freight cars.

And even the 6 axle diesels of that time were relatively short. An SD7 is 60' long, even E8's are only 70' long.

And these are facts/features that allow the use of tighter curves - OR - give even greater impact to my goals. A string of long modern cars 20 actual feet long might be 20 or 30 cars.

A string of 34' hoppers 20 actual feet long is 50 cars.........

Sheldon

    

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Posted by ATLANTIC CENTRAL on Monday, June 15, 2020 7:42 PM

rrinker

 You have to consider WHEN Armstrong wrote his material. Both the hobby world and the prototype.

 Brass? The floodgates didn't open on that until the early 60's and PFM.

 The prototype was still running mostly shorter cars and shorter locos. Yeah there were giants just retiring, like the Big Boy - but thoose were RARE locos, regardless of how many models of them are made. The everyday loco was the 2-8-0 and 2-8-2. Or 4 axle diesels.

 Modern locos are much larger. Modern rolling stock is bigger - 89 foot stack cars and articulated auto racks, and 60 foot box cars. So you need to up the radius for the classes of curves.

 My 4-8-4's don't look silly on 30" radius curves. The tender can couple to the loco in the closest position. It can handle these curves at warp speed. Most anything I run cn handle #6 turnouts at ridiculous speeds as well, but I am using #8's for mainline crossovers. I am actively considering #5s in the yard, because no big locos or passenger cars will run there, just mostly 40 foot and shorter cars and small switchers. A random 50 foot car here or there. Engine terminal will have #6s, because the biggest locos I have can handle those no problem. The only reason I even drew it out as #6 was because that's the size Peco was going to introduce first in code 70. But it's been over 2 years and all we got so far is the flex track, I'm not holding my breath. If I have to mix rail size then I might as well use the turnout that gets the most out of the space. 

 In the context of the early to mid 50's, Armstrong's classification of curves as sharp, conventional, and broad fits botht he model world and the prototypical world. For MOST modelers. To model lines using some of the true giants of the rails, you may indeed have to adjust those upwards. 

 Space is usually the limiting factor. Few people have hangers. Everything needs to be compressed, including the track. I'd love to just do a single deck, but I can't fit what I want with 30" radius mainline curves. If I expanded that to 36", I wouldn't even get a double track in the part I'm working on now, not with sufficient clearance from the walls and then between the tracks. SO 30" and double deck it will be.

                                --Randy

 

Completely agreed.

And I can meet my goals on one level with 36" curves in my 1500 sq ft.

And I don't have a hanger, but I do have virtually all of a nice rancher basement.

I only have share it with a modern boiler, water heater and well tank.

And I have the same 4-8-4 as you, and yes they are fine on 30" curves, and their 70" drivers give them a compact rigid wheel base of only 19.25'.

So they look really good on 36" curves.

Sheldon

    

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Posted by BRAKIE on Monday, June 15, 2020 7:39 PM

 My thoughts is if one must use 18" he or she should run small engines like 4 axle diesels or nothing larger then a 2-8-0 and 40 and 50' cars.

Today's highly detailed cars including 72- 89' freight cars and full lenght passenger cars one should try for 30-36" curves even though long cars might still look silly on 30" curves.

As far as that goes and this hit home while designing a new Slate Creek switching layout 63-72' freight cars requires at least a #6 switch or a long Peco to look right. I suppose a size 8 switch might be better?  

Good LDEs and the type of equipment that will be used on the layout should always be considered while designing a layout..

Larry

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Posted by rrinker on Monday, June 15, 2020 6:52 PM

 You have to consider WHEN Armstrong wrote his material. Both the hobby world and the prototype.

 Brass? The floodgates didn't open on that until the early 60's and PFM.

 The prototype was still running mostly shorter cars and shorter locos. Yeah there were giants just retiring, like the Big Boy - but thoose were RARE locos, regardless of how many models of them are made. The everyday loco was the 2-8-0 and 2-8-2. Or 4 axle diesels.

 Modern locos are much larger. Modern rolling stock is bigger - 89 foot stack cars and articulated auto racks, and 60 foot box cars. So you need to up the radius for the classes of curves.

 My 4-8-4's don't look silly on 30" radius curves. The tender can couple to the loco in the closest position. It can handle these curves at warp speed. Most anything I run cn handle #6 turnouts at ridiculous speeds as well, but I am using #8's for mainline crossovers. I am actively considering #5s in the yard, because no big locos or passenger cars will run there, just mostly 40 foot and shorter cars and small switchers. A random 50 foot car here or there. Engine terminal will have #6s, because the biggest locos I have can handle those no problem. The only reason I even drew it out as #6 was because that's the size Peco was going to introduce first in code 70. But it's been over 2 years and all we got so far is the flex track, I'm not holding my breath. If I have to mix rail size then I might as well use the turnout that gets the most out of the space. 

 In the context of the early to mid 50's, Armstrong's classification of curves as sharp, conventional, and broad fits botht he model world and the prototypical world. For MOST modelers. To model lines using some of the true giants of the rails, you may indeed have to adjust those upwards. 

 Space is usually the limiting factor. Few people have hangers. Everything needs to be compressed, including the track. I'd love to just do a single deck, but I can't fit what I want with 30" radius mainline curves. If I expanded that to 36", I wouldn't even get a double track in the part I'm working on now, not with sufficient clearance from the walls and then between the tracks. SO 30" and double deck it will be.

                                --Randy


Modeling the Reading Railroad in the 1950's

 

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Posted by ATLANTIC CENTRAL on Monday, June 15, 2020 4:57 PM

I have worn out two copies of "Track planning for realistic operation"...........

And I think JA brought science and planning to layout design in ways never considered as a whole process before him.

On this topic of curves.......and yes I have a nice size space, for my last two layouts and my next one........many decades ago, based on my experiances at the Severna Park Model Railroad Club, I decided any attempt to model a Class I railroad in HO scale required 36" radius curves.

It should be noted here that the Severna Park layout is not all that large, it is only 12' x 36', yet it has 36" minimum mainline curves.

Is it the best track plan in the world? No. Does it work for the goals and space of that group? Yes.

Pictures and a track plan can be found in the June 1973 issue of MR for those having archives access or your own library. 

The exact nature of compromise in this hobby is left up to each modeler, as each has a different set of goals, different space, different skills, different resources, etc.

Can really nice layouts be built with 30" radius? or even 24" radius? Sure.

Many consider my standards extreem, maybe they are. I model 1953, my longest freight car is 75', and there are not very many of them. More on passenger cars later.

My mainline minimum, hidden or visable, is 36" radius. If passenger cars go there, it has 36" or larger curves.

Since the mainline is double track, That means that many curves are 38" or larger.

At one spot there are 5 tracks going around a curve as a yard lead joins the mainline and a double track passenger station lead joins the mainline. So the outer most track is in the neighborhood of 46" radius.

Being an around the room layout with two peninulas, there are only three places where major curves are viewed from the outside.

Passenger cars - I have some 80' passenger cars, they however do not make up most of my passenger car fleet. 

Most of my passenger cars are selectively compressed in the 72' - 75' range, or are models of prototypes that were less than 80' long.

My passenger cars are close coupled with working diaphragms - that touch - all the time. I consider this necessary!

For me, overall visual effect is more important than total accuracy of each car.

Locomotives - even with 36" curves, there are no 2-10-4's on my layout. There are not even any 80" driver 4-8-4's.

I limit steam locomotive rigid driver wheelbases to a scale 21' - the USRA light 2-10-2 is my longest rigid wheelbase steam loco.

All of this is about appearance and reliable operation.

I run long trains, 35-50 cars is really typical, sometimes longer. The main freight yard on the new layout will be 22' long, that's over forty 40' cars.

So my curves are beyond broad.........

I could have packed more layout into my 1500 sq ft if my yard was shorter and my curves tighter - but I don't need or want that, I want to capture a specific "feel" of just how immense railroading is.

Sheldon

    

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Posted by cuyama on Monday, June 15, 2020 4:04 PM

riogrande5761
So what I saw generally being done in the many MR magazine articles I read concerning moderate and larger layouts, was 30 inch minimums. 

Statistically, quite a few of the mid-sized layouts I design for others use less than 30" radius in HO (or the equivalent in other scales).

Just for a quick check to see if my clients' requirements were unusual, I looked at the HO layouts that come up in the MR Track Plan Database for sizes 100 sq. ft. to 300 sq. ft. (I think that most would consider that "Mid-Sized" or even large)

I looked at the first 25 that turned up (eliminating Narrow Gauge and purely logging/quarry layouts).

For those 25 layouts, Average (Mean) minimum radius is 24.5". Median minimum radius is 24". Suprisingly, a handful at 18"!

Maybe "Conventional" is, well, still kinda conventional.

Edit: That said, I often recommend 28" with easments in HO for decent performance with most all equipment in a mid-sized space. Broader curves are always preferred when they can work for the concept in the space, of course.

Byron

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Posted by riogrande5761 on Monday, June 15, 2020 3:24 PM

selector
John's contribution was to craft a framework for track plan design.  It was a tool set, with rationale provided in his running commentary.  Maybe the word 'dean' is too strong, or hard to appreciate in modern parlance.  Nowadays, the buzzword is 'influencer'.  Whatever the term one uses, he encouraged a lot of nice layouts by making the thinking behind their creation lucid, methodical, and efficient.

For whatever reason, dean of layout design has been coined for years regarding John Armstrong.  As Cuyuma pointed out, we don't need to find a new title because it seems to strong to the newer enlightened among us.  Perhaps history is judging him more harshly as time goes by, and that is often the case as we watch the world around us evolve.

I used to be an avid reader of MR magazine in the 70's, 80's and 90's. and by the mid-1980's I did notice a trend of moderate sized layouts and that was that the standard minimum radius I kept seeing over and over and over was 30 inches.  It was a pattern that repeated and stood out.   But that "trend" that I was seeing seemed to translate in my mind, after enough time and articles, to "conventional" in John Armstrongs nomenclature.  

con·ven·tion·al
/kənˈven(t)SH(ə)n(ə)l/
 Learn to pronounce
 
adjective
 
  1. based on or in accordance with what is generally done 

So what I saw generally being done in the many MR magazine articles I read concerning moderate and larger layouts, was 30 inch minimums.  In this day and age of increased sensistivities, maybe the smaller layouts feel some how left out when "conventional" curves are not possible in small spaces.  But if it makes some feel better, then call 24 inch radius curves conventional.  It's just a label or term and what is "generally done" may be open to debate.

As noted, a 4x8 layout (another convention based on the standard sheet size of plywood) may be built in a space that can fit a layout a bit larger and 24 inch curves can be accomodated - allowing more variety of rolling stock.  Simply bump up the width from 48 inches to 54 inches (4.5 feet) and heck you could have 24 inch curves.  Whether or not some one feels they want to be conventional or something else, that's anyones call.

But for those who take issue with curve labels, just despense with them and do what you can manage and just keep in mine the limitations associated.

Regardless of these "finer points", Track Planning for Realisitc Operation has a lot of great track planning basics and principles and remains one of my go-to references when I design layouts.

As many are aware, the process of layout design is usually a matter of making compromises based on a list of (here we go) Given's and Druthers!  Kisses

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Posted by cuyama on Monday, June 15, 2020 3:19 PM

selector
Maybe the word 'dean' is too strong, or hard to appreciate in modern parlance.

Armstrong innovated or popularized so many things beyond curve radius classifications that we use today – including things like narrow spiral footprints and mushroom benchwork. One or two people not understanding the use of the term "Dean" is not reason enough to scramble for a different word. IMHO, YMMV, etc.

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Posted by selector on Monday, June 15, 2020 3:15 PM

As it evolves, the hobby moves on several fronts.  Brass has effectively been supplanted as the go-to for high details and accuracy, and for realism.  Not entirely, not by quite a long shot in fact, but you still pay about three to five times the price for brass (new). A toy J1 2-10-4 in times of old, IF it were available commercially and not scratch-built in John's day, would decidedly have been seen as a rougher approximation/toy, and not so much as a fine replica in scale the way the Paragon version is.  That model needs 22" minimum, according to BLI, although our hosts and I found through trials that it could creep through 21" curves.  

John's somewhat arbitrary range for the smallest type of curvature still encompasses 22".  I don't know that it should change, or that his category range should change.  If in 2026 nothing runs on curves less than 24", his lower range will be almost meaningless in the context of the day's modeling, so I agree with Fred just above.

John's contribution was to craft a framework for track plan design.  It was a tool set, with rationale provided in his running commentary.  Maybe the word 'dean' is too strong, or hard to appreciate in modern parlance.  Nowadays, the buzzword is 'influencer'.  Whatever the term one uses, he encouraged a lot of nice layouts by making the thinking behind their creation lucid, methodical, and efficient.

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Posted by riogrande5761 on Monday, June 15, 2020 3:12 PM

Eilif
Sure even bigger curves look better, but for actual operations most will run on 22"/24" and virtually everything will run on 30".    Nothing preventing folks who have the space for going for wider, grander curves, but his numbers still encompass virtually all HO rolling stock and thus are still useful today.   I'm only a couple years into the hobby, but is there anything that won't run on a 30" curve?

With more and more rolling stock being made to a higher degree of fidelity, some have even reported issues with interference of underbody detail on even a 50' box car!

Here are a few anecdotal experiences I had:

Before BLI came out with their HO CZ passenger cars, I had a set of Kumata (Oriental Ltd/High Country Brass) passenger cars.  One would work on 32 inch curve but another would derail and needed a bit larger radius.

Before the above, Chuck Macklin who is a train book dealer, brought some brass CN&W heavy weight passenger cars over to my garage layout, which had 30 inch minimum curves.  Those cars shorted out on the curve due to the detail on the truck side frames hitting the body of the cars.  

So 30-inches seems generous but I discovered that it's rather tight when it comes to brass some passenger cars.  Of course brass steam engines can have issues on 30-inch curves too or even larger.

Most mass produced plastic rolling stock is manufactured or has compromises to allow operation on 24 inch minimum curves.  Some six axle loco's will operate on 18 inch curves.

But the curve thing reminds me back when I was gaming and remember reading about minimum computer specs recommended.  A lesson I took from that is that you generally don't want to run computer games on the absolute minimum computer specs.  Likewise with model trains, operating them on the minimum recommended by manufacturer may be ok, or as happens with Walthers passenger cars, may be not so much.  I'm going with 32-inch minimums and have a bunch of Walthers passenger cars now and am hoping things will work out well, after all, 32 inches is 8 inches above the minimum 24 recommended.  I have read that changing out the wheels for IMRC wheel sets has made a big difference for those who reported problems with their Walthers passenger car rolling abilities.

Anyway, I realize people have to work with what they got, but in some cases, with a little effort, curves can be increase a bit and result in better experience.  At low radii such as 20 or 24 inches, increasing a couple inches could make a sizable difference in operability, especially if rolling stock is already at the edge of being able to operate at minimum such as 24 inches.

Rio Grande.  The Action Road  - Focus 1977-1983

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Posted by fwright on Monday, June 15, 2020 2:50 PM

What they need instead is for producers of railroad equipment to simply be simply more forthright about what curve measurements their rolling stock will reliably operate on.   I suspect they don't care much what Armostrong thought a conventional curve was, but they do want to know what curve their latest, super-detailed 89' rolling stock is going to require.

Who is volunteering to do the testing?  And what happens if the manufacturer's test track is significantly better in curve joints and lack of kinks than the average Joe's trackwork?  Should the manufacturer degrade the minimum radius because Fred's trackwork is too sloppy to reliably run at the manufacturer's minimum radius?

The club I participate in was trying to establish what the minimum reliable radius for HOn3 operation should be.  Some HOn3 brass locomotives were/are known for being "stiff" and requiring more than 18" radius.  But we couldn't test everything in advance.  So the club settled on eased 24" minimum radius.  Is this enough?  So far, it has been.  But I can imagine there could come a time that a "stiff" K-36 or K-37 or large Shay would struggle with these curves.

Fred W

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Posted by Eilif on Monday, June 15, 2020 2:30 PM

carl425

I'll wager that in Armstrong's time as is the case now, some models will run on 18" curves, some models require 30" curves and most models will run on 24" curves.  This makes 18" for tight, 24" for conventional and 30" for broad as accurate now as it was then.

 

Did a bit of thinking and looking at the Armstrong standards and I think you're absolutely correct.  I assume we look at the standards as denoting reliable running and in that respect I think it's absolutley right.  Sure even bigger curves look better, but for actual operations most will run on 22"/24" and virtually everything will run on 30".    Nothing preventing folks who have the space for going for wider, grander curves, but his numbers still encompass virtually all HO rolling stock and thus are still useful today.
 
I'm only a couple years into the hobby, but is there anything that won't run on a 30" curve?

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Posted by carl425 on Monday, June 15, 2020 1:52 PM

I'll wager that in Armstrong's time as is the case now, some models will run on 18" curves, some models require 30" curves and most models will run on 24" curves.  This makes 18" for tight, 24" for conventional and 30" for broad as accurate now as it was then.

Keep in mind also that as equipment has gotten longer, models have more often been altered to run on tighter than normal curves.  I'd say it's balanced out.

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Posted by Doughless on Monday, June 15, 2020 1:38 PM

Confused.  Is this a continuation of another thread?

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Posted by riogrande5761 on Monday, June 15, 2020 1:16 PM

Aye.

Rio Grande.  The Action Road  - Focus 1977-1983

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