The title of your thread suggests you meant to include the stipulation that the curves would be negotiated by a 4-8-4, and if 20" curves would be okay. The answer is...probably. However, there is a real possibility that your particular loco may not like them at all. For example, in a recent thread, I gave the opinion, based on BLI's Niagara literature, that 22" is the min, but someone else said their N&W J did fine on 18 curves. I'll bet the J had 80" drivers, while the S1b only had 79"ers. So, since the BLI J was very likely the same platform under the boiler, I felt my advice was reasonable.
FWIW, all locos will look much better on the largest curves you can shoehorn into your space. Also, and I have been disagreed with on this point, your steamers won't look much different on a 22" curve vice a 28" curve. Once you add a full 10", your eye will really appreciate the difference. And, if your tracklaying is good, they will always run much better on the larger.
FWIW anything under 30" would look ugly. But that is my not so humble opinion. Plenty of people will disagree.
Have a look in the November MR for some photos that illustrate that bigger is always better when we are talking about curve radius. I can't say off hand which page because the mag is at home and I am not. You'll find it I am sure. Towards the back as I recall. Actually the photos are passenger cars, but same deal.
Many manufacturers claim that their big engines will go around an incredibly small radius. Well they will, but they look terrible in my view because they over hang so grossly and the gap between loco and tender would be a gross safety hazard.
But then it's your railroad empire. Do what you have to in the space that you must work with.
EDIT NEXT DAY. The article starts on page 54. Photos on Page 55.
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
I'd say that if you have room for 30" radius, go for it. Any 4-8-4 will look much better with a wider radius, and most models, either plastic or brass should negotiate it without any problems. It will also look much better if you go for bigger steam, period, such as a 2-10-2, 2-10-4 or most articulateds. And generally speaking, a wider radius--even on a slight grade--means you can haul more cars behind that 4-8-4 of yours.
Just out of curiosity, which model 4-8-4 were you thinking of?
Tom
Tom View my layout photos! http://s299.photobucket.com/albums/mm310/TWhite-014/Rio%20Grande%20Yuba%20River%20Sub One can NEVER have too many Articulateds!
For me, the november MR was about the most depressing thing ever. It basically said that unless you have 30" curves, you shouldn't bother running passenger cars, long locos or basically anything interesting. And I was looking forward to the Trix 32-axle Schnabel*...
* The manufacturer states it can go through a 15" curve, which is pretty amazing for a car that's about 28" long.
I probably COULD make a layout with 30" mainline curves, but I wouldn't have room for anything more complex than an oval. Ergo, I am feeling very :-( about it.
Agamemnon wrote:For me, the november MR was about the most depressing thing ever. It basically said that unless you have 30" curves, you shouldn't bother running passenger cars, long locos or basically anything interesting. And I was looking forward to the Trix 32-axle Schnabel*... * The manufacturer states it can go through a 15" curve, which is pretty amazing for a car that's about 28" long. I probably COULD make a layout with 30" mainline curves, but I wouldn't have room for anything more complex than an oval. Ergo, I am feeling very :-( about it.
Agamemnon wrote: For me, the november MR was about the most depressing thing ever. It basically said that unless you have 30" curves, you shouldn't bother running passenger cars, long locos or basically anything interesting. And I was looking forward to the Trix 32-axle Schnabel*... * The manufacturer states it can go through a 15" curve, which is pretty amazing for a car that's about 28" long. I probably COULD make a layout with 30" mainline curves, but I wouldn't have room for anything more complex than an oval. Ergo, I am feeling very :-( about it.
I'm lucky enough to have enough space to do a 30" minimum layout, but still agree with you about the tone of the thing. It really did come across sort of condescending.
Even with a relatively large space for my layout, I had to go with 28" min mainline radius (for the inner track on a dual mainline) and down to 24-25" in hidden areas to get anything even approaching the mainline length I wanted... And a couple of those hidden areas will be so ONLY because they're smaller radius. My perception is that 30" radius curves throughout is unrealistic for probably the majority of layouts - particularly if (as you say) you want more than a loop. Certainly I'd say even the feartured layouts in the magazine itself have <30" mainline a clear majority of the time. So treating it as sort of a "bare minimum" simply excludes a huge chunk of the hobby...
dean_1230 wrote:if you run your 28" long Schnabel around a circle of track with a radius of 15 inches, the angle swept out from the front of the car to the back fo the car is 138°. The center of the Schnabel car will be approximately 10 inches from the center of the track. hence, you would have to have a clear area almost 10 inches on the inside of such a curve in order to run it. man, wouldn't that be fun to watch!!!
Hitsua wrote: The way my around the roof layout is to be setup, will leave me with a 30'' radius, or a 20''. I'm sure it could make a 30'' pretty simple, but what is the smallest that it could make, and still be aesthetically pleasing?
FACT: MANUFATURERS today design their mechanism's to appeal to the segment of the market they are targeting.
Most expensive BRASS 4-8-4's would just barely squeak through a #6 turnout. (My $1000 4-8-8-2 would derail).
TODAY's 4-8-4 mechanisms are designed for 22" radii and #6 turnouts, by adopting smaller-than-prototype drivers and more lateral play (slop) in their design. They are heading for where the market is. 36" radius used to be the standard. Today it is 22".
AESTHETICALLY: A 4-8-4 looks weird on 22" radii.
NMRA says something like 3X -5X the length in inches for " of radius. That translates to 36"r minimum for a 12" engine or car. My personal tests for aesthetic's: are for an 80' - 85' passenger cars to not look 'toylike' on a curve takes 46"-48"r.- so I put 46" 90o curves onto 4' square ply sections (cut into semi-triangles), to make 48" corners. The rest was pure fill-in.
YOUR (PERSONAL) AETHETICS come into play here, as well as the reasons for having them. Differet Tastes. Different Strokes et al. In short, different Thresholds on what you find tolerable. The layout will reflect your Personalty. That is as it should be. YOU will be the one running it.
However; For me, the opportunity to use 30" curves should not be wasted.
Austin--
The Bachmann Daylight locos (both 'Daylight' and 'War Baby') will comfortably take a 22" radius, because of compromises in their driving wheel diameter and spacing. However, they're not very good pullers, unless you're willing to spend the money to put the Bowser conversion kits under them, so I assume you're thinking of waiting for the future release of the one from PSC (or BLI, I'm not sure), which will probably need a 24" minimum. I have 34" minimum radius on my layout, and two Balboa brass SP GS locos, which look good on the curves and would probably take as little as a 28" minimum radius if I were forced to compromise. However, since you say that you can afford it, I think you should hold out for a 30" minimum. As I said in my last post, even larger wheel-base steam should have no trouble negotiating a 30" minimum radius. Who knows, if you like SP steam, you might start thinking of a Cab-forward, and you'll REALLY want a 30" minimum for that monster, LOL!
This is a bit off-topic, but it's peripherally radius-related. What does a "#4 turnout" mean? I assume it's some kind of standard notation, but what's the turn radius of the diverging track? Inquiring minds want to know.
I'm fortunate, perhaps, in that I've grown up watching Finnish show layouts and leafing through catalogs of every German manufacturer out there. This means I've grown accustomed to seeing passenger cars on a 18" to 24" curve and do not consider it aberrant (provided they have decent close couplings and mounts so that the distance between cars is kept to a minimum).
It means that the diverging route moves off-axis from the through route at the rate of 1/4 the distance travelled from the point rail tips to the frog, and beyond. This is because American turnouts have a straight diverging route after the points, so the frog angle matches that rate of diversion and beyond. The rate of curvature, in essence, is about 18", I think..not positive..., for a #4 turnout, and about 26-28" radius for a #6.
I will stand to be corrected, but that should be quite close.
Try this little card:
EDIT: Not so easy to read. Sorry
Five out of four people have trouble with fractions. -AnonymousThree may keep a secret, if two of them are dead. -Benjamin Franklin "You don't have to be Jeeves to love butlers, but it helps." (Followers of Levi's Real Jewish Rye will get this one) -Ed K "A potted watch never boils." -Ed Kowal If it's not fun, why do it ? -Ben & Jerry
bush9245 wrote:EDIT: Not so easy to read. Sorry
You're right, I can almost read the text on that one.
bush9245 wrote: Try this little card: EDIT: Not so easy to read. Sorry
I think it says the #4 is about 16.75" for a substitution radius, and the #6 is 36"...seems high to me, but...
The #4.5, which many N. American manufacturers call a #4 is 19.8", plus or minus.
#5 is 24"