Is 072 Diameter Large Enough for Articulated Steam

Presuming you're running a hi-rail locomotive:

• Operationally, yes, provided you have enough clearance between the track and the walls. Any 3-rail item produced to-date will negotiate O-72 curves.
• Aesthetically, you'd be much better off with O-120 or larger if you had the space because trains look better on larger curves.

I have all those locos and I run them all on O-72

Pretty much everyone makes their locomotives able to run on O72.  Going less than O72 is the problem for these larger locomotives.  Also, you'll find many people say that these large locomotive look bad at O72.  I personally don't mind the look, they are toys after all.

So, yes, O72 is fine for all locomotives.

As the guys mention they will all operate on 072 track. Visiting layouts, seems both the UP Big Boy and Challenger have the biggest issues with front end overhang striking objects not placed exceedingly far from the tracks when using 072. Some of the 2-10-4's having the cab strike objects as well, though not as far out as the walkway of a BB.

I'm sure you will enjoy running whatever trains you chose. Always interesting to see new track plans, Good Luck with your layout!

My 3rd Rail Y6b is running on Atlas O-63 curves (but wider switches) ... so, you're safe with that.

Good luck.

Yes, all of the mentioned articulated engines negotiate my 072 curves with no problem.

Should you ever decide to, or need to, run NYC Niagaras or Union Pacific 9000 type engines, this is where the radius of curves and their importance becomes more prevalent.

irregardless of their toy status, if you've ever seen articulated locomotives operating on 6 to 10° curves (min prototype mainline) you might be able to see their point.  O72 in O gauge translates to a 40° curve.  the minimum curve a Big Boy (1:1 scale) could negotiate was 20° or what would be an O144 curve in O gauge.

cheers...gary

72 radius will work fine as hot water says, as long as you!

Definitely yes!  The key factor is the spacing of your track on curves, i.e. at least 5 1/2" inches apart from center rail to center rail and center rail to tunnel or wall clearance there should be no problems.

Alan

Exactly what I was going to say. An articulated will have considerable overhang even on O72 curves. Whether it looks "acceptable" is your decision.