minimum radius

[Anonymous]

In HO, what should I plan for a minimum radius if I plan to run 2-8-2 locos? How about 2-8-8-2's?

[Anonymous]

Several of the larger steam locos can operate on 18"
radius.
Lifelike 2-8-8-2, 18"-MR March 2000
Riv Allegheny 2-6-6-6, 18" MR Feb. 2002
Trix Big Boy 4-8-8-4, 18" MR April 2002

These will operate on 18" but with considerable overhang.
18" use to be the norm but with today's larger steam/diesels and longer passenger cars 22"-24" are recommended.
Walthers new budd passenger cars require 24" so if
you have the space go for the larger radius.

[Anonymous]

If your space makes it possible, your 2-8-2 would look and perform better on 22"-24" radius, rather than 18".
For large articulateds, whatever they are capable of for tight radius, is secondary to looks. They just don't look good on anything less than 30" radius, and 36" is much preferred.Some modelers use a tighter radius for hidden trackage, to save space. This works if there is a transition curve, but make sure the trackage is accessible, and that adequate clearance is there for the overhang of long equipment.
Don't forget that any crossovers you may design in are just as important as curve radii....use a minimum of #6 turnouts for any steam loco, or any 12 wheel diesel for that matter.
..good luck & regards / Mike

[dknelson]

be careful because some locomotives will RUN on a small radius but any cars pulled will derail. Too many MR reviews focus on the engine's Min radius as if they are run by themselves.
Dave Nelson

[Anonymous]

You are right on, Dave.

[BR60103]

Can I throw this into the mix:
For appearance, the radius should be large enough that your longest piece of rolling stock doesn't take more than an eighth of the curve. Should probably be more, but this isn't too bad.
You can get away with sharper radii on hidden tracks.
I remember the old Lionel layouts where four coaches would take a whole end curve.
--David

[Anonymous]

David - What are you calling "the curve"? How many degrees? I tried working it out for a 360 degree curve and came up with a radius that is only about 70% of the car length - which is obviously wrong.
Bill K

[BR60103]

Sorry. I was picturing a 180 degree curve in my mind. Radius about 2 1/2 times length.
--David