If space dictates it, 30" will be fine so long as you don't operate at mach-1 or faster speeds.
My new layout has 24" radius minimum (on main) and can (via testing) operate the 6-axle loco's and autorack cars. The key is smooth trackwork and smooth operation of the train, no sudden elevation changes, no jack-rabbit starts and stops.
But I also operate at "prototyipically slow" {under 40 smph} speeds. (And most of my rolling stock is smaller, due to layout size. But I can run big stuff if I wish.)
While "larger looks better", if space dictates 30", 30" is fine. (Like my space dictating the 24" radius in one area. 24" required, 24" it is.)
Ricky W.
HO scale Proto-freelancer.
My Railroad rules:
1: It's my railroad, my rules.
2: It's for having fun and enjoyment.
3: Any objections, consult above rules.
Thank you, gentlemen, truly appreciate your input.
I agree with Sheldon...a 30" radius is the smallest that I have on my layout, (actually three of them), used mainly as a turn-around for locomotives and some rolling stock that has to have a particular end leading when in-transit...
Wayne
So, 15" radius in N scale translates to 27.5" radius in HO, but there are other things to consider. N scale trucks and couplers are much more for giving and have wider swing and tolerances proportionally than HO.
I would strongly recommend 32" radius or greater in HO, and 36" is a much more desirable radius especially for modern equipment.
Sheldon
I am going to go with Ray on this.
30" is ok, but 32" is ideal.
Rich
Alton Junction
I think you will be fine with 30" curves if you observe the usual guidelines e.g. no short S curves (and split with a straightaway if possible); some straight track before entering the turnout from a curve; wathch out for S curves in the yard ladders, etc.
You could probably use #5 turnouts, if the trackwork is done well, and you are not running at full speed. Ultimately, the space dictates what kind of geometry you end up using...
YouTube Channel
Website
30" is pushing it for +80' cars. 32" would be better if you can eek out a few extra inches. #6 turnouts should be fine for most locations, but #8 turnouts would be better for crossovers.
But, you have to do what needs to be done, so I wouldn't fret about sticking with 30" radius.
Ray
I like to run big modern road diesels and 60'-80' long cars. I use 15" radius curves in my N scale world with #6 turnouts. In HO will those locos and cars work well with 30" radius curves and #6 turnouts?