Scale?

What scale are you modeling?

Do you want a "walk-in" or are duck-unders / removable sections for access to the middle ok?

HO scale.    Anything is on

HO scale. 

Anything is on the table, but I am not a huge fan of duck-unders or removable sections.

Carbondale Central

I believe that the Carbondale Central track plan by Malcolm Furlow from the late 80's in Model Railroader was designed for 8x8, very similar to the Byron Henderson plan you posted.

Mike in CO

"Anything is on the table,

     The big advantage of a duck under or removable section for this size space is they would let you maximize the curve radius and minimize any reach problems. If you are young and healthy a duckunder is no problem especially if the layout is mounted about chest high. Larger curves viewed from the inside of the curve look a lot better than smaller turnback curves viewed from the outside of the curves (higher mounting also improves the view).  I'd try to extend the layout out of the alcove as much as possible to increase the length, aiming for a twice around the walls loops with a couple of towns, one on each side of the layout. With a passing siding and some industries at each town one has multiple choices for operations scenarios, and places to pass trains and park cars for fun or railfan type running........DaveB

Drop Down Bridge

Hi BDiddle,

Consider a drop down bridge for the continuous running track. 

I've got four tracks on two levels on my N scale bridge...so HO should pose no problems.

My drop down bridge is even curved 90 degrees to facilitate the track layout.

Use microswitches to interrupt the bridge and approach track power, to prevent disaster.

Roundy Round

No offense but you may want to plan on a design that will not appear to be a continuous loop but coming from and going somewhere. The continuous connection can still be there for running in locos or testing equipment. 

Think about what you like in railroading. What era, equipment, industry/country/city environ, switching, passenger trains, and even inspiration from a real railroad - current or past.

If you are just interested in watching them run then consider a yard where a variety of trains to choose from. After building my "dream" layout, I found that I am happy with switching and short runs to and from the yard. Others do model railroading differently and enjoy running the long trains. Find what you like and then design the layout.

My two cents - for free ;- )

....letting the boys play will take priority over operations.

I'm answering your statement of top priority.

This grandpa built a Lionel layout at 30 inch height, so the little guys could see what was happening. When I work on the layout or run it I use a desk chair. Also I prefer the larger trains for the little hands, and the Lionels are a little better able to withstand being treated like a football.

You could consider a layout for the boys built underneath Daddy's full-height layout. Either Lionel or - for their age - wooden Thomas.

If you go with just the HO layout, I have two suggestions:

Install a couple of Atlas rerailer sections so the boys can put the trains on the track easily.

Build the benchwork in sections, and cut the tracks at the boundaries. Use short sections of track to bridge the gaps (see published methods for modular layouts). Start at 30 inch height using a chair for yourself. As the boys grow, you can raise the layout a few inches; this is where the separatable sections will make life easy.

I think you will find that a low level for the layout will be easier and safer than having the boys perch on stools or ladders.

DrJolS

MR Trackplan Database and Google Searches

The site you referenced has a lot of good info.  So doing some research was a great first step.  Given your space, there are walk-in types of layouts like you linked to, or table-top layouts that range from 4x8 and better 5x9s that can be a little less rectangular.  In September 1995 MR there was an article featuring a '5x9' that was cut from a 4x8 sheet to form a non-rectangular shape.  You can Google Drago and East Ridge Railway and find the trackplan online.  So in the end, there are good options for your space.  MR Trackplan Database is a good source if you have access.  If not, PM me.  There are also various trackplan books and MR articles. You can gather a bunch for ideas and narrow your search to what will fit, and then consider what type of plan you like.

Track Plan books

That is a good idea. Check Amazon as most of them are out of print. Stay away from the John Armstrong books. They are for the most part large basement empire types, but some of the others by Kalmbach Publishing Model Railroaders owner have some small plans which range from 4x8 or smaller to room size some of which could work for your space and the kids too. About 4x8's, keep in mind that in some cases you can split it down the center and put each half against a wall and then connect the ends.

If you run small loco's you can get away with a 18 inch radius curve at each end and then make a long u shaped dog bone layout using some 4x8 plans.  18 in radius = 36 in diameter loop. Make your end loop bench work 40 inches wide and you can walk in instead of having a lift bridge.

You might let us know how it works out as there is a lot of interest in kids and trains here and ideas that work out are always appreciated.

Jack