High banked Daytona's or "Super Elevation"

[JoeW]

Hi Gang
Here I go again seeking your thoughts, opinions and best of all experience. On occasion I contemplate super elevated turns, the Kato super elevated sectional tracks are really cool but I am looking to develop a rule of thumb when super elevating turns in non fixed sections.  How much is too much and when to use it?  How well it works with tighter radius track? Graduating curvature in and out of the super elevation?
I am currently experimenting with up to 3 percent. What is the most extreme examples you know of or experimented with.  Although prototypical standards are good real world examples the tight radius typical of model railroading are so highly compressed it is not likely we justify super elevation and for that matter the way the prototype calculates curvature is different from the way we do anyway.  In this case I am not really concerned about prototypical standards as I am going after "the look". 
JoeW

[C855B]

Have you done a search yet on "superelevation" here? We've had some chatter about it. Obviously it has zero merit in terms of N scale physics, but like you say we're after "the look". The consensus has been finding a happy medium in raising the outer rail, which seems to be in the .020-.030" neighborhood. More than .030" starts looking toy-like.

[davefoxx]

I don't know the degree of superelevation on my layout, but I know I used five layers of masking tape under the outer rail.  If I were to do it again, I would use six or seven layers, because the effect is not as nearly as noticeable as I would like.  I've recently seen some historical prototype pictures of the line that I'm modeling, and some of those curves had some significant superelevation.

I'm using superelevation in curves as tight as 12-3/8" radius.  I run long cars and have never had a stringlining problem.  The key is to use horizontal and vertical easements into the curve.  I stairstep the layers of masking tape to ease the transition.

DFF

[Santa Fe Guy]

Joe.
On my SFRSD I used pieces of 10 thou styrene under the outer cross ties. It gets covered by the ballast and I did it mostly for the look.
Regards Rod.

[Cajonpassfan]

Joe, I'm with Rod, go for the look. We make a lot of compromises to get our layouts to "look" right. On the prototype, superelevation is mostly a function of speed; no point in superelevating very sharp curves where the speed is very restricted (due to sharp curvature, or grades, or both). But out on the open main, with higher speeds, I don't mind exaggerating a bit, because it looks very cool and railroady
Otto K.

[CodyO]

I used Kato superelavated curves in my helix 15 3/8 inner radius 2% grade and 15" of rise no problems ever with running long trains up it I have had problems with couplers though and had trains cut lose near the top and then come running back down the entire helix and inti staging intact.

[Santa Fe Guy]

Nice pic Otto that does look very cool.
Rod.

[JoeW]

Thanks Rod, Otto, Dave, C855B and Cody
I suppose I may be over thinking this but I really wanted to hear your thoughts.  Anyway thank you so much I greatly appreciate the encouragement and ideas. 
Your old pal
JoeW

[JMaurer1]

Super elevation (AKA cant...no apostrophe) in the prototype had everything to do with the speed of the train. High speed passenger trains used it to counter act the momentum when it came to a curve (Newtons first law of motion: Every object in a state of uniform motion tends to remain in that state of motion unless an external force is applied to it.). Something going straight wants to keep going straight. If you turn the train then everything IN the train wants to keep going straight (and slide off the table). By super elevating the track it increases the downward force helping things to stay where they currently were. Mainlines with passenger traffic would have a lot of super elevation...branch lines and less traveled routes not so much if any.

At the ends of a curve, the amount of cant cannot change from zero to its maximum immediately. It must change (ramp) gradually in a track transition curve. The length of the transition depends on the maximum allowable speed—the higher the speed, the greater length is required.

For the United States standard maximum unbalanced superelevation of 75 mm (3 in), the formula is:

    v_{max}={\sqrt {\frac {E_{a}+3}{0.00066d}}}

Bottom line is in the real world the maximum value of cant (the height of the outer rail above the inner rail) for a standard gauge railway is about 6 in or 5 to 10%.

If you are modelling a well traveled mainline you can have as much as you want (depending on the train speed limits) and probably go more towards the 10% (so it is more noticeable). For N scale this would be about 1mm (9mm rail / 10% = .9mm). Then again, it's your railroad and you can do whatever you want.