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Curve Radius For Pacific 4-6-2 Engine
Bruce writes:
“I just got given a nice Pacific 4-6-2 engine HO scale. Q: what curve radius should this engine be able to negotiate? Q: How would this compare to a Spectrum 2-6-6-2 USRA engine which a mate has? Thoughts please.”
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You should be able to run it around a 18″ Rad. curve. However, it would love you if it were on 26 or larger. Brass articulated engines require a larger curve due to the front engine is usually hinged and the the rear is fixed and rigid. Your Spectrum should slide through a 18″ Rad., also. But the appearance is worse than horrible.
Measure the distance from the outside diameter of the front driver to the last driver, the engine should easily handle a radius 3 times that distance.
Ron, That’s a great little hack. I’ll be sure to remember it. “The curve radius = three time the wheelbase of the driving wheels.
Bruce,
If you “just got” the locomotive do you till have the paperwork? That will usually tell you its minimum radius requirements. Minimum requirements do not equate with looking good though. I wouldn’t want to be under 24″ radius with your loco and the Spectrum 2-6-6-2 shouldn’t see anything less than 30″ radius from an appearance point of view.
As Hervey says, look at the manufacturer’s specification for minimum curve radius. If this is not in the instruction sheet (it certainly should be for larger steam locos !), go to the maker’s website and check the description.
I’ve got a whole bunch of 4-6-2’s they run fine on my 18″ and 22″ curves… some better than others, but that’s more relative to the age of the Loco’s. I have Mantua, Rivarossi, Bachmann, Mehano, Pico, Hornsby and Roco examples.