riogrande5761They came up with a series of formulars on car length vs. curve radii and I found it very though provoking!
That data was actually first posted on the Layout Design SIG's site and is a useful curve radius rule-of-thumb.
One of the things that has changed since the original publication of Armstrong's Track Planning for Realistic Operation is that real-life freight equipment and locomotives have grown in length (such as auto carriers). The rule-of-thumb helps estimate curve radius based on equipment length.
Having said all that, minimum radius is always a matter of trade-offs between the minimum needed for good operation, what looks good to the layout owner's eye, and what will allow a layout that meets the owner's concept and vision to fit in the room.
I recently completed a fairly large multi-deck custom HO plan for a client that is based in the modern era. Although he would have liked broader curves for appearance’ sake, we maxed out at 32” minimum on the visible layout and 30” in hidden areas. Horizontal easements will help with appearance and operation. We just couldn’t fit anything broader in the space without compromising on his desires for a long mainline run, etc.
John Armstrong once told a room of layout owners and designers that the only thing worse than a minimum radius that was too small was one that was too large. While he was speaking slightly tongue-in-cheek, I’ve certainly seen cases myself where folks sacrificed too much (IMHO) for a broader minimum radius than they absolutely needed.
Byron
Layout Design GalleryLayout Design Special Interest Group
mlehman Crunching that data sounds like a great article idea for the statistically inclined among us...that's not me
Crunching that data sounds like a great article idea for the statistically inclined among us...that's not me
Are you sure? Aren't we all secretly afraid to learn that ours is smaller than average?
I have the right to remain silent. By posting here I have given up that right and accept that anything I say can and will be used as evidence to critique me.
Mike Lehman
Urbana, IL
riogrande5761Ah, so that includes back to the 1930's
Nope. It only includes back to the point where the magazine was produced digitally. I'm not sure of the exact date that started, but it was way after the 80's.
riogrande5761why don't you break that data base up into
Yep, that would be interesting, but our friends at MR use the term "database" rather casually. "Folder" would be a more accurate description.
carl425 riogrande5761 That said, I didn't base my comments on a track plan data base but by the many articles I read since the 1980's in MR magazine The Track Plan Database comes from the articles in the magazine. Every plan lists the issue that it appeared in.
riogrande5761 That said, I didn't base my comments on a track plan data base but by the many articles I read since the 1980's in MR magazine
The Track Plan Database comes from the articles in the magazine. Every plan lists the issue that it appeared in.
Ah, so that includes back to the 1930's or way back when the magazine started. Hmm... so why don't you break that data base up into time slices and see if the minimum radius average increase over time. That would be interesting to see; you see I was only basing my memories and thoughts on articles I've read since the early 1980's or so. It's very possible as model railroaders got more progressive and had garage or modest basement, my guess is you'll find the average minimums may be higher. It would be interesting to see.
Oh, and my idea of modest is something, lets put a rough number on it, thats bigger than 200 square feet, just to throw out a number. My smallish basement room for my smallish sized layout is 10x18' - I settled on 32" minimum.
Rio Grande. The Action Road - Focus 1977-1983
mlehmanif you reran the data as min R vs SF and included layouts up through 500 to 600 SF
I assumed Jim's definition of "modest" to mean about the size of his own layout which as I recall is 18 X 10 - 180 sq ft. My definition is "spare room" sized, which fits what I thought Jim was suggesting. 600 square feet is 20 x 30 - not a modest layout.
Also the minimum is listed, but that doesn't necessarily mean that all or even most of the curves on the layout are that tight. I am at 200 sq ft and my minimum is 24" so right in the center of the pack. But, most of the curves are more like 30" or greater and I have easements into the few sharper ones. My EM-1 may not look good on the tighter curves but most of the time it looks fine and I have no derailment issues anywhere regardless of what is running.
Personally I didn't want to give up desired features just to keep all of the curves broad. Now if I was working on a 400+ sq ft layout that would probably change things. I bet many of those here would say the same.
Huntington Junction - Freelance based on the B&O and C&O in coal country before the merger... doing it my way. Now working on phase 3. - Walt
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riogrande5761When I forget to post messages like a lawyer and use absolutes like "every",
Your posts don't need to look like they were writen by a lawyer, but they don't need to look like they were writen by a radius snob either.
riogrande5761That said, I didn't base my comments on a track plan data base but by the many articles I read since the 1980's in MR magazine
carl425I collected the specified minimum radius on layouts from the 100-300 square feet category (this sounds "modest" to me). I left out narrow gauge layouts, layouts where minimum was not specified, and one 400_ sq.ft. layout that was in the wrong group...I knew going in that every layout wasn't 30" or greater, but I was a little surprised to see that it was only 27%.
I suspect Jim's working definition of modest size is actually at the top end of your range of modest. Point being, where there's space, people prefer to go wide. if you reran the data as min R vs SF and included layouts up through 500 to 600 SF, the relationship he was pointing out tends to hold up. Obviously, some caution about absolute statements is recommended , but aside from semantics the point remains that people generally don't build big layouts with small min R unless they're doing traction. Even in narrowgauge, larger than 24" is preferred if you have the space for it...and we're obviously talking HO here, as O and N would be at opposite ends of this spectrum
When I forget to post messages like a lawyer and use absolutes like "every", I frequently get burned. Chalk another one up - it will help me to choose my words more carefully next time. And of course, undefined words like "modest" can have ways of developing a life of their own. Modest is to one person maybe different to the next.
I think that it's still worth noting that it has really stood out to me after reading many articles that 30-inches minimum radius came up over and over as the dominant standard. That said, I didn't base my comments on a track plan data base but by the many articles I read since the 1980's in MR magazine, and it stood out to me that 30" was the standard minimum I saw repeated over and over in sizable layouts. And frankly I"m too lazy to go do an exhaustive study of what magazines I still have left - I'm going to enjoy my free time doing other things thank you. Probably tweaking the parameters of a survey, I'd guess the average minimum may very well increase - cause my memory isn't that bad.
Smaller minimums seem to remain popular, probably due to space limitations but also probably because of old fashion standards seem to linger including that old 4x8 straight jacket. I still argue strongly that you aren't doing yourself any favors. It's always ALWAYS a good idea to try to increase your curve minimums as much as you can manage to make your trains look better and operate better.
It reminds me of a tech forum of I've been a member of for years, people come in and ask for advice on flat screen TV's and how big they should get. A similar sort of advice exists there too, whatever TV size you think will be big enough, go a least one size bigger because you ultimately will wish you did after the fact. Same goes for model trains. If you think 22-inch curves will do, sure, you might be able to get your trains to stay on the tracks reliably, but how will they look? Will you wish you chose larger. But as the old saying goes, YMMV. I am never satisfied with sharper curves and even 32-inch I've chosen look quite sharp under 89' flat cars or autoracks.
I feel that since John Armstrongs day when sharper curves were more the norm, things have changed and since then it's becoming more and more popular, at least among the progressive modelers, to up the radii of what they find satisfying touse. I still argue that the better terminology would be:
18" curves - very sharp24" curves - sharp30" curves - conventional40" and above - broad (an arbitrary number based on nothing in particular.
Well, maybe I've been reading too many progressive type of articles and forums, such as MRH where there was a study done on what curve radii and what is necessary to make model trains look good on those curves. They came up with a series of formulars on car length vs. curve radii and I found it very though provoking! No we can't always have those ginormous radii that make our models look more prototypical, but it definitely drives home a major point, bigger where possible is better.
SouthPenn I would think the radius of curves is determined not only by the room size, but also what you are running. And by what time period your railroad is set in.
I would think the radius of curves is determined not only by the room size, but also what you are running. And by what time period your railroad is set in.
After seeing this quote in another thread and knowing it not to be correct...
riogrande5761every modest home layout in MR magazine since the early 1980's had 30 inch minimum curves, I've always considered anything much less than is getting into the sharp range
I decided to do a little homework to see what the MR Trackplan Database could tell me about this.
I collected the specified minimum radius on layouts from the 100-300 square feet category (this sounds "modest" to me). I left out narrow gauge layouts, layouts where minimum was not specified, and one 400_ sq.ft. layout that was in the wrong group. Where a mainline and any other radius was specified, I used the mainline number. I ended up with 82 layouts.
Of the 82,
60 had a minimum radius less than 30"
22 had a minimum radius of 30" or more
The median radius was 24"
I think it's interesting that this still matches up with John Armstrong's numbers of 18, 24 and 30 for sharp, conventional and broad.
I knew going in that every layout wasn't 30" or greater, but I was a little surprised to see that it was only 27%.