what fits in between 22" and 18" radius curves?

[union pacific 844]

hi  what fits in between 22" and 18" radius curves?

[Jerrys HO]

Scenery

[ryeguyisme]

If you're looking to do something like 20 inch radius track, try experimenting by mixing 22inch with 18 inch radii. I've done this before with sectional snap track with good results back in my early teens. I have since evolved to flex track

[jward]

to expand upon what rye said, alternating  22r and 18r sections willgive you an approximate 20r curve. you use 4 22r and 3 18r, laid out 22-18-22-18-22-18-22. that will give you an 180 degree curve.

[Jerrys HO]

Sorry for the first reply I did not realize you were looking for a track line.
Jeff and Rye are right on. I have done this on several locations through out my layout.

Jerry

[Joe Satnik]

Dear All,

John Armstrong shows 2-1/4" separation triple-track semi-circles using sectional track in

"Atlas Custom-Line Layouts for HO Scale Railroads" (2nd Edition) 1957, 1971, pg. 43

with the following formulas:

18"R:  Six 18"R-30 degrees (pretty straight-forward).

20.25"R:

One 22"R-22.5 degrees,
One 18"R-15 degrees,  (= Half 18"R)
Two 22"R-22.5 degrees,
One 18"R-15 degrees, (See note 3)
Two 22"R-22.5 degrees,
One 18"R-15 degrees,
One 22"R-22.5 degrees.

22.5"R:

Four 22"R-22.5 degrees,
One 1" Straight
Four 22"R-22.5 degrees

Note 1.) Cars were shorter then (longer locos and rolling stock may not clear with 2-1/4" spacing).

Note 2.) A 22-1/2" radius outer curve puts you very close to the fence on a 4' wide layout.

Note 3.) Substitute two 18"R-7.5 degree (cut) curves to split the semi-circle into 2 quarter circles and expand the layout width.   

Hope this helps.

Sincerely,

Joe Satnik

[Doneldon]

UP-

Jerry might have been right the first time.

Trying to run parallel tracks with 18", 20" and 22" curves is asking for trouble. Unless you separate your tracks by a really bad looking distance you will have all kinds of clearance problems. The only way to escape them will be to confine yourself to small locomotives and short rolling stock. Now you can have a terrific layout with small equipment, but that's a decision which will be constantly challenged by all of the terrific new and not so new models in larger sizes.

Also, remember that a ~20" curve made of a series of 18" and 22" curves won't be a smooth one but a series of changing arcs which will be very obvious when the ersatz 20" curve sits between the parallel and smooth 18" and 22" curvatures.

                                                                                                                                                  -- D

[jward]

the clearance issue isn't as big as you'd think. a few years back, on a previous layout, i did some experiments on parallel tracks with the inner curve at 24r. i found that 2 1/8" centers were more than adequate to keep even the longest cars from sideswiping on these curves. thus, the curve centers in the book joe mentioned will work well. an alternative would be to offset the centers of the arcs of the curves by 1/2" or so but keep the 18r, 20r and 22r. your straights will still be on 2" centers, but the offset of the arcs will give up to 2 1/2" clearance on the curves.

[Len]

If you want a smooth 20in radius curve between the inner and outer loops, you could use Shinohara NS Code 100 20in radius curves, Walthers item: 669-149.

You'll have to mount it on cork, and add grey or black ballast, to match up with steel or NS EZ-Track.

Len