@Ryan Selvius posted:Anybody know what the minimum curve would be for body mount couplers on 21” passenger cars?
Well, I tend to draw on my years of investing in the land of (pardon me!) HO.
I would offer this simple comparison...
First of all, an O72 curve (36" radius) is equivalent to an 18" radius curve in HO. Probably good enough for 40'-50' cars with body-mounted couplers.
When it comes to HO passenger cars, though, I reflect on the notation that some large manufacturers...like Walthers...would include on their RTR full-length (85') passenger cars. They would specify 24" minimum radius. In the O realm that would work out to O96 curves. And this was to accommodate the body-mounted couplers on those cars...which still were designed to have some additional side-to-side flexibility over a fully rigid mount.
Other HO manufacturers...like Athearn, Roundhouse, Con-Cor, etc...would offer 'shorty' passenger cars...analogous to the 15" and 18" offerings in O3R...as a concession to the popularity of 18" (sometimes 22") radius curves offered in complete HO train starter sets.
Bottom line re full-length scale passenger cars with body-mounted couplers?...I think you're going to have a LOT of problems on anything less than O96 (48" radius) curves. Just a prediction, mind you...no personal experience. Oh, and hope that you'll never have to back up a string of full-length passenger cars with body-mounted couplers through O72 curves and comparable switches, cross-overs, and ladder tracks...to name a few.
Rots o' ruck, pal!
Re wheel flanges...I also have Ross/Gargraves exclusively on the layout and often replace the plastic wheels on current production Athearn O trucks with metal wheel/axles (O2R) like those sold by Intermountain. Very few major operational problems, but I haven't done anything with the switches...yet...and those cars (mostly cabooses from kits) do, indeed, have a bit of a dip and rattle going through the turnouts. C'est la vie.
My layout is also built to O72 minimum curves. There are many curves of larger radius...up to O128. But I prefer running the 15" passenger cars. They just look better snaking around the bends. But that's IMHO. I have longer cars...18"...but don't run them as often. I have also succumbed to a very few select 21" passenger sets...GGD, only...for sentimental reasons. Perhaps someday they'll stretch their 'legs' on a club layout with curves that complement their length. Maybe.
The other advice, though, among the responses...try running O2R equipment, see what happens...is probably the best encouragement. I'd avoid mach-level O3R around-the-tree speeds though!
Let us know how it goes!
KD
