riogrande5761As I mentioned to Keven, the question of curve radii boils down to application.
True. However, just focusing on mainline, modern modeling tends to distort the historicasl use of these terms. Yep, everything's bigger, needs broader curves, etc.
But that is essentially reducing the argument to modeling the present or very recent past.
Let's not forget that there are still plenty of people doing narrowgauge. And it's not that everything NG works on 18" radius. It doesn't. But industrial lines do even sharper in the normal course of business. Traction is not so much modeled these days, but also fits in the JA system quite nicely. That's leaving aside those who model the 50s and earlier, where - excepting many passenger cars - lots of stuff was fine with 18" curves.
JA also notes his reduction of curves to 3 broad classes is an attempt to simplify the 14 varieties of curves found in the NMRA Recommended Practices. Since this is an RP, even the NMRA's set of definitions is only a suggestion. In ant case, JA notes that selection needs to be based on a number of factors besides simply measuring and labeling.
Then there's the fact that even modern day lines have certain limits below the allowed minimums, given the life span of many lines. Industrial and branch line traffic is often fine with more restrictive practices, so long as operators know that restrictions are in place and what cars and locos are allowed on certain lines.
How JA defines what works on which of his broad classes of curves snd this info still seems pertinent. JA also supplies examples of these definitions for scales larger and smaller than HO.
Importantly, JA ends his discussion by noting that "Experimentation s an aid to selection of curves" so he's well aware of that defining the changes needed to get certain gear to operate properly is an important part of the process. We can offer all the help in the world online. In the end, it's what happens when the wheel hits the rail is what really counts.
Mike Lehman
Urbana, IL
@Elif, as always YMMV.
For those who have progressed into large personal or club layouts, they dont need to use the Armstrong curve recommendations anyway. 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.
Regarding JA's. curve recommendations, one of the more important things is to read the discussion on rolling stock vs. curves, which is still pretty relevant as cautionary items. Basically, as you get to sharper curves, you may need to take special consideration with respect to interference of things like underbody details and possible modifications, if necessary. That is going to be more salient than the labeling of sharp, conventional and broad curve labeling that I'm going to be made very sorry I mentioned even mentioned. Anyway, y'll enjoy yourselves doing the 20 lashes with a wet noodle thing.
As for forthrightness, that's a discussion you'll need to have with manufacturers. As I mentioned, Walthers recommends 24 inches for passenger cars but experienced hobbyists have found something larger than that is much better.
Rio Grande. The Action Road - Focus 1977-1983
I don't think anyone is in a place to convince railroaders to uniformly reorder the Armstrong curve classification. Also, I suspect the majority of layouts -especially beginner and casual hobbyist layotus- operate in a limited space and still would find his standards represent their reality.
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IRONROOSTER I'm not sure changing the definition of very sharp/sharp/conventional/broad would be helpful.
I'm not sure changing the definition of very sharp/sharp/conventional/broad would be helpful.
Yes true. And for that matter, why would John Armstrong even set such a labeling scheme in the first place? (Sharp, Conventional, Broad). Conventions of the time.
My only point is that what some consider to be sharp, conventional or broad has changed a bit over time. If any terminology is meaningless to you, well, blame John Armstrong for bringing it up in the first place - he was very naughty!
Never-the-less book and much of the content is still very useful. His discussion on "squares" didn't really work for me either, so I discarded that part. Not every part of Track Planning for Realistic Operation will be useful to everyone, but a lot of it will be.
First, who is going to set the definition and maintain it as necessary. Second, it will be confusing because older models/articles and newer models/articles will be using different values which will confuse buyers/readers. Interestingly, the NMRA RP11 for curvature has 13 different classes of curves for model railroads.
Second, it will be confusing because older models/articles and newer models/articles will be using different values which will confuse buyers/readers.
Interestingly, the NMRA RP11 for curvature has 13 different classes of curves for model railroads.
To answer the first question, apparently JA had the audacity to set the definition. But since he is no longer alive, he cannot maintain or justify it, apart from what he wrote in the book.
When discussing curves, I think a lot of us tend to forget that a lot of folks have small layouts. The hobby press is full of large layouts. But I suspect there a lot of casual hobbyists who have a 4x8 or little larger. For them the current definitions are good. For those of us a little more involved, perhaps we should the RP 11 definitions and call our curves Class F or L or P, etc. Paul
For those of us a little more involved, perhaps we should the RP 11 definitions and call our curves Class F or L or P, etc.
Paul
As I mentioned to Keven, the question of curve radii boils down to application. Obviously the smaller the layout and/or space, the more curve radii will be limited. Also, when operating shorter rolling stock, curve minimums can be tighter and still work well.
When person comes here and discusses buidling a 4x8 layout or something close to that in size, I still would ask what they are planning to run and even if not long cars, there may be a possibility they may wish to run longer rolling stock in the future. Thus, if they can increase the size of the layout a few inches, at least they could, perhaps used 22 and 24 1/2 inch curves (if a double track oval) rather than 18 and 22 inch curves, and that would allow perhaps full length passenger cars or longer freight cars to still operate without major issues. It's only a small increase but could yield dividends in operation possibilities.
So maybe some do forget about small layouts, but in this and other forums, they are common place so there are considerations that can be discussed to hopefully steer to a good experience.
First, who is going to set the definition and maintain it as necessary.
When discussing curves, I think a lot of us tend to forget that a lot of folks have small layouts. The hobby press is full of large layouts. But I suspect there a lot of casual hobbyists who have a 4x8 or little larger. For them the current definitions are good.
SeeYou190I have a very hard time communicating my tone in things I type on this forum. I once responded to a question about figure painting, and got about a half dozen "why are you so angry" responses.
It's true, typed message often convey or don't convey what was intended by the author. Emoticons were invented partly to help in that regard. And to be fair, communicating in ways to overcome lack of facial or body language can be a challege on forums and in emails. It can take extra effort to avoid being misconstrued. It a can be learned but even then unintended consequences still happen.
Re: Track standards and John Armstrongs book, things have evolved in the hobby since Track Planning for Realistic Operations was last revised, but much of the information is still fundementally sound and worth digesting and putting into action. Very much worth reading.
Very true. When I tell some people I am using 24 inch as the minimum radius for hidden and branchline track, I get the "that is pretty darned sharp curve" response. Our perception of tight curves has certainly changed. -Kevin
It has, but curves need to taken in context too. For those running shorter rolling stock, 24 inches may be totally fine. OTOH, those running 89' auto-racks or flat cars or 85' passenger equipment, may be less than happy with 24-inch curves.
John Armstrong does discuss those kinds of compromises in his book and that full length passenger cars (very much relevant in his time too) may need modifications or special consideration if to be reliably run on 24-inch curves.
I've read that Walthers passenger cars, even though the recommended minimum radius is 24-incyes, it is reported they don't work very well on those curves and many recommend 30" radius or more.
A growing number of modelers are interested in post-1990 model trains and as a rule, the models are longer, engines and freight cars both. So there is justification for conventional curves to be larger than they used to be, being bumped up from 24 inches to 28 or 30 inch radius.