HO Clearance

Our club is working our new layout and we have the lower benchwork in place and are starting the staging tracks. Some folks want 2.5" centers on the tangent tracks, and 3" center on curves. Now the inside curve is a minimum of 30" radius(with 36" radius on the staging area). There seems to be concern about running Challengers and Big Boys pn the inside curve(36" radius) hiting long cars like passenger cars on the adjacent track. I tend to think 3" is rather excessive, and the NMRA S-8 Standard indicates 2.5" for long wheelbase articulateds. Anyone have experiance with running these engines?

Jim Bernier

I’m with you Jim, I think the guys are wasting space unnecessarily by going with those wider centers. The NMRA specs are proven to work, why go bigger? Those larger engines are articulated for a reason, and should work just fine. I would be more concerned with long wheelbase passenger and freight cars.

It’s going to depend pretty much on whether or not those Challengers and Big Boys are the newer double-articulated wheelbase types from Rivarossi and Genesis, or single-articulated wheelbase brass. I’ve got 34"-36" curves on a passing track on my layout, and laid the centers 2.5 as NMRA suggested, and there’s no way I can run my brass Yellowstones or Challengers on the inside curve with passenger cars on the outside–the overhang even on MY radii are too much on the articulateds. I found that out when I sideswiped some new Walther’s standard pullmans when I ran a Yellowstone around them on the inside. I should have gone with a MINIMUM of 3" centers.
Tom [xx(]