radius

[jim2272]

Thank you Avondaleguy! I've been rebuilding a small N guage layout and I had to go with a Bachmann turnout (9 3/4" radius) to put in a return loop. Are there any more 9 3/4" radius turnouts available without the plastic roadbed?

[Anonymous]

jim2272-

Most turnouts are not actually of a given radius; instead, the tracks diverge a tthe points at some radius, then straighten out as they pass through the frog. The #4 or #8 or whatever refers to the angle that is created between these straight track segments. It actually means the ratio of the length of the straight-through route versus the perpendicular separation between the routes. That is, a #4 switch has a frog that has the rails crossing such that they spread apart by one foot after four feet of length. A #8 switch diverges one foot after eight feet of length, and thus represents a shallower angle.

Peco makes switches that are a constant radius rather than "flattened" through the frog. I am not sure what their radii match. They make really good switches, which makes up for the fact that a constant-radius turnout usually causes problems in operation. As a general rule, one should use the largest # (or broadest radius) switch that will fit in a given location.

[jim2272]

How do you determine turnout radius from looking at the box? Atlas makes #4-#8 , Peco makes small radius. Help!
jim2272

[Anonymous]

I thank you all for the feed back. The layout I have planned is 3' x 5' , and was going to use a 16" radius for the mainline.[:D]

[Anonymous]

Dear very similar screen name [:)][:D],
I have been asking for what minimum radius I should use for 4-8-4s and 4-8-2s. The answer that I have gotten is around 24". Being as the Big Boys were articulated, they had a wheel base of similar to a 4-8-2 (I think). I know for sure that the 4-8-8-4s could negotiate 20 degree curves in real life, meaning that their minimum radius should probably be only al little broader than a 4-8-4 if not smaller. I would think that you might be able to run one in maybe a 12" radius curve. I would advise you, however, to call the manufacturer, and also try it out on several radii before purchasing, if possible. If you can manage a 18" radius curve, I would say that would be safe, but I doubt you want to do that in N.

I hope this has helped,
Daniel

[Anonymous]

When I started in HO the min radius was 24", my layout uses 36" min. My larger locomotives and 85" cars look better on this radius. N guage is about half HO, so I would think 12 to 18 " would work.

[dehusman]

Ther are two answers, the minimum radius that the engine will work and the radius it will look well on.

Operationally its probably about 11 inches (a guess)

Look good its probably 18-24 inches.

Dave H.

[Anonymous]

I would like to know what the min. radius is for an n scale 4-8-8-4 big boy would be?[:p]