One really nice effect of using flex track (not so much the otherwise very fine Micro Engineering variety, which is quite stiff and takes special skills) is that it creates a reasonably good approximation of a cubic spiral outward from a 'free floating' apex. If you fix, securely, the last two inches of each end of a length of flex, but at intended angles leading to tangents, the apex of the resultant curve will be approached on both sides by a close approximation of an 'eased' curve. It looks good and it functions almost as well as the real deal.
I think the more important issue is the transition into the sharp curve.
I would very strongly recommend that the OP read up on transition spiraling and make himself a template or jig that eases the transition from straight into any sharp curve. Many years ago MR actually published a spiral template that could be copied onto appropriate stock and cut out for use: this was for outside rail if I remember correctly and I don't remember how it was adjusted for different curve radii, or if it could be used 'directly' for something as sharp as 15" radius, but that might be a starting place for a 'buildable' solution.
gregcwhat about hiding tight curve in tunnels?
.
I do this. My layout will drop to 22 inch in the tunnels.
Tightest visible mainline is 36 inches, tightest visible switching is 24 inches.
-Kevin
Living the dream.
Alexander - If you're building an industrial switching layout, or electric traction layout, or whatever, and understand the limitations of the sharp curves, that's great. I think the big issue I've seen is people/newbies will post that they want to build an HO layout with 18" or 15" curves on it, but want to run SD-70s, 89' TOFC cars, and Amtrak Superliners - usually with a double or triple track mainline. That's when people step in recommending broader curves or a smaller scale.
what about hiding tight curve in tunnels?
greg - Philadelphia & Reading / Reading
If the issue is appearance and not functionality, there are ways to mitigate the views. A well-placed shrub or boulder or structure or something can restrict views and sightlines to help hide your unattractive overhang.
Robert
LINK to SNSR Blog
IMO, any radius is fine as long as it operates. If you're trying to pull off a realistic look, then the surrounding scenery should dictate the need for sharp radius.
Wharf's, urban areas, fitting between a tunnel and a stream, etc, all require the prototype to make things a bit tighter than if they had gobs of flat plywood to work with. Logging trains, coal trains, ore trains tend to have to sneak their way around physical barriers, as do any cars being switched in many urban areas.
Plan accordingly.
- Douglas
LION decided that all curves on layout of him would be 26" or greater. So smart LION builded table with 24" curves. Now all I would need to do was lay the track matching the curve and it would be at least 26" (Right?) The next track would be 28", the third would be 30" and the fourth track would be 32" radius. (After all subway layout of LION does have four track mane lions.
Well it WAS a good theory, but some of my curves are still way sharper than I planned for.
Fortunately, subway cars are only 50' long and so can transverse my surves whatever they are. : )
YOU on the udder hand can milk it for all it is worth, Industrial and switching yards pay no attention to minimum radius. If you engine and car can make the curve, all well and good. Even if your engine cannot make that last curve into a wearhouse, a couple of reach cars will work just fine and will add interest to your opperation.
GO for it!
ROAR
The Route of the Broadway Lion The Largest Subway Layout in North Dakota.
Here there be cats. LIONS with CAMERAS
Hi Alex,
Like has been said, all that really matters is if your equipment runs on it, and it looks good to your eye, then you're good to go.
The big issue, as I've learned, pertains to expandability. As others have mentioned, if you keep your equipment small, you'll be fine, but you will be locked in. Running larger equipment will probably require you to redo your track. And this is what standards are usually designed to address, whether in model railroading or anything else - that middle-of-the-road balance between reliability, desirability and practicality.
But even such tight curves are to be found in prototypical operation. In researching my layout, I came across some images of a wye in operation on my prototype, the Arcade and Attica, that is extremely tight by today's standards (it's about a 200ft radius), but they use only GE 44-tonners (for revenue - they do run a 2-8-0 on excursions). So your curve and equipment choices are borne out in prototype.
- Adam
When all else fails, wing it!
If you want to use 15" radius HO curves with all their plusses and minuses, go for it.
But if your space is still the one you described in your earlier thread, not sure why you would need to.http://cs.trains.com/mrr/f/11/t/264043.aspx
Good luck with your layout.
Layout Design GalleryLayout Design Special Interest Group
Thanks for all of the encouragement.
The post was not really to ask any real question. Just thinking about the subliminal message we all put out to avoid curves like the plague. I myself have seen what people say and was concerned about all of the things that might happen. I made the post because I see other threads about radii, but none talking about when it’s really ok. If anything, I was trying to just get a stamp of approval for the ideas in my head.
when i started a layout about 5 years ago in an empty bedroom, i built a simple pt-to-pt with a 15" loop at one end (like John Allen's original layout). I wanted to build something and didn't want to get hung up in "analysis paralysis". I decided to recognize its limitation and bought some small switchers (a Rdg B8). A Rdg I-10 i really like is on the shelf. I hand laid turnouts. I'm experimented with a turntable and built an elevator. I recently completed a signalling system with Arduinos. All this is easier with a small layout.
I have plans to expand the loop to something bigger if it becomes a problem. I'd also like to re-lay a turnout as a curved turnout. I'm also a member of the Pacific Southern club.
its taken me a few years, but rather than over analyze, I have something I can operate and enjoy today.
It's your layout and you don't really need our validation or discussion to put in sharp curves if you know your rolling stock will operate reliably on your planned curves.
As always, make sure your minimum radius will allow reliable operation for all your equipment.
Case closed. /FORK
Rio Grande. The Action Road - Focus 1977-1983
I would not go below 18" in HO. but as long as your cars are 40', this looks fine and not toylike at all. Flatcars can be a bit longer without looking toylike. At 50' cars, they still perform fine but the illusion of space starts to diminish on the 18" radius curves (why I got rid of almost all my larger cars). Now engines are another mater and small ones look fine like my Proto 0-6-0's and 0-8-0's or my early diesels. Also of note they looked fine on outside curves too and with the space I had at the time I could have picked up to a 36" radius but did not because of what I was running. If you are running autoracks, they may run on 22" but look weird on anything smaller than 42" though some find the ok at 39".
cuyama Another good complementary reference is the Layout Design SIG's Curve-Radius-Rules-of-Thumb. This distinguishes between what radii might be made to mostly work, what will work well all of the time, and what looks good -- all based on car length.
Another good complementary reference is the Layout Design SIG's Curve-Radius-Rules-of-Thumb. This distinguishes between what radii might be made to mostly work, what will work well all of the time, and what looks good -- all based on car length.
No one ever talks about the old-timey small stuff. My biggest frieght car is 36 ft.
But I get it. 3X.
Chip
Building the Rock Ridge Railroad with the slowest construction crew west of the Pecos.
John Allens origonal Ghore and Daphetid layout had 14 inch radius (on a grade). As his trains got larger so did the radii.
If you run short cars and short engines it will be fine.
Steve
The only place I have 15 inch curves on my layout is in the subway. I had to change to longer shank couplers to make it reliable.
Dave
Lackawanna Route of the Phoebe Snow
Alexander, as others have suggested, you have already answered your question. Your test worked so go for it!
Bottom line is that it is your railway so you can do what you want if it works.
I'm just a dude with a bad back having a lot of fun with model trains, and finally building a layout!
The New York harbor float terminals such as the Harlem Transfer used 90' and 104' concentric curves. They worked them with boxcabs and GE 44 tonners. For an ISL using maximum 40' rolling stock you will be fine at 15". Just don't try to push modern six axle diesels and auto-racks around them.
As I just posted in a thread on the General forum. Read:
https://www.nmra.org/sites/default/files/standards/sandrp/pdf/rp-7.2_curved_track_centers_july_2017.pdf
For information on recommended timeframes and equipment for various radius curves.
Ray
AlexanderOk now here is the hard part: I am dealing with 15” curves
There is nothing wrong with 15" radius curves in HO scale. At one time, that was the accepted minimum radius.
As long as you stick to short freight cars and small diesel locomotives, you should have no problems with 15" radius curves and #4 turnouts.
From the sound of your post, it seems you already know that.
Well if your 44 tonner will handle it all, go for it! Do what works. No one is going to laugh at your layout becuase you need 15" radius.
Not sure if that is your question.
Mike.
My You Tube
tstage So what's your question...????
So what's your question...????
Unless he is asking if there is any reason, other than people say not too, for not using sharp radii, I am clueless as to the question myself.
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.
What size is or will be your layout?
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.
The old hands tell us not to. The professionals tell us not to. So why not do it?
My layout will undoubtedly have more senic potential with sharper curves. It wont look nice, it isn’t like the prototype, just chose a smaller scale...
Welp here we go.
lets get some things out of the way shall we?
I don't run bullet trains.
I don’t own a car that is larger than 45’.
If its longer than 8 cars, its not my layout.
My largest engine is a GE 44 tonner.
I don’t mind if it looks out of place.
I just want a layout that I will enjoy looking at and say “Im the one who made that”
I set up a test curve and it works dandy.
My track work will impress you (when Im not rushed).
I try to keep away from tight curves, and will use 18 and 22s when I can.
Ok now here is the hard part: I am dealing with 15” curves
(I cringe when I say 15” too)