For readers wondering about the reference, the Carol Valley layout was in MR July 2015. Subscribers may find the track plan here:http://mrr.trains.com/how-to/track-plan-database/2015/05/carol-valley-rr
Building a rectangular island-style layout wider than 4' in HO is a great idea, as it will allow you to broaden the radii beyond the typical "sacred sheet" 4X8 minimums. But note that this will also have the effect of reducing the length of the straight tracks, so you would likely want to increase the length beyond 8’ as well. Broader curves and a larger layout area will also allow you to ease the grades a little bit, important for lighter motive power such as a 4-4-0.
One you have increased the overall size, the island layout begins to become more of a room-filler. The HO design from my website that you referenced places the layout around the edges and the people in the middle, which can be more enjoyable for viewing and operation. Although I personally would find the switching-puzzle nature of the Equinox section tedious pretty quickly, if you want to try it you will likely find that it is a bit tricky to accommodate in a roughly 5X9 or 5X10 rectangle and easier against a wall with the wye leg extending into the room.
In the larger space you have available, you could open up the “water wings” plan a bit. A client has done just that in a version of that layout that I hope to be featured in the commercial press soon. This layout was built in sections and moved to the final layout room to be assembled. It would certainly be possible to build part of the “water wings” plan, put it into operation, and then build more later. Personally, I’d start with the yard and a bit of track extending in each direction for switch leads. And then you could build on later.
My personal opinion is that it’s no more difficult (and maybe even easier) to build benchwork around the room with a technique like L-girder than to build a rectangular table.
UPJEng041. Will this work? 2. How well will the trains operate on the tight radius curves?
In answer to your questions, reliable operation is always easier to achieve with broader radii, though many HO models will run on 18” radius curves. In a layout with grades, the tight curves greatly increase the effective grade, which can be problematic for small steam engines.
UPJEng04Would I be better off with a different design?
I think rectangles are overrated in model railroads, but I’m prejudiced.
Good luck with your layout.
Byron
Layout Design GalleryLayout Design Special Interest Group
I tend to also lean towards an around the walls design. Im not entirely a fan of running in circles (its not my thing), but I understand the usefulness of the concept. Byron's plan is a good one. Given that you have a somewhat larger space than Byron's plan calls for, you can either push the plan to the walls to open space, or build it in a 8x10' space of your room, leaving aisles for access on two sides. That allows you to add that dotted line passing siding, extend the green line (I assume thats a scenic divider) and possibly add a coal tipple (albeit a small one), coal truck dump or small pulpwood yard in the place of the access hole (bottom left side of Byrons drawing).
Edit:
The suggestion I just made sacrifices the interchange track location. Re-locating it may or may not be possible. Possibly move it to the top left corner.
With your room size I would consider an around the room shelf layout. My layout is a 2' deep shelf built around a 12' by 12' room. This allows more switching options than a 4'x8' sheet of plywood.